2,000 Greater & Lesser Mysteries

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From: paj@uk.co.gec-mrc (Paul Johnson) Date: 23 Jul 93 12:26:24 GMT Newsgroups: sci.skeptic,sci.answers,news.answers Subject: sci.skeptic FAQ: The Frequently Questioned Answers Archive-name: skeptic-faq Last-modified: 93/07/23 Version: @(#)skeptic-faq.text 1.11 The Frequently Questioned Answers ================================= Introduction ============ This is the sci.skeptic FAQ. It is intended to provide a factual base for most of the commonly discussed topics on sci.skeptic. Unfortunately I don't have much time to do this in, and anyway a FAQ should be the Distilled Wisdom of the Net rather than just My Arrogant Opinion, so I invite submissions and let all the net experts out there fill in the details. Submissions from any point of view and on any sci.skeptic topic are welcomed, but please keep them short and to the point. The ideal submission is a short summary with one or two references to other literature. I have added comments in square brackets where I think more information is particularly needed, but don't let that stop you sending something else. Many FAQs, including this one, are available on the archive site rtfm.mit.edu in the directory pub/usenet/news.answers. The name under which a FAQ is archived appears in the Archive-name line at the top of the article. This FAQ is archived as skeptic-faq. In general it is not very useful to criticise areas of the FAQ as "not explaining it properly". If you want to see something changed then please write a submission which explains it better. Grammar and spelling corrections are always welcome though. If you are reading this with a newsreader and want to follow up on something, please copy the question to the subject line. This is more informative than a reference to the entire FAQ. Please mail submissions and comments to <paj@gec-mrc.co.uk>. If that bounces, try <paj%uk.co.gec-mrc@ukc.ac.uk>, which explicitly routes your email via the UK backbone. This is in no way an "official" FAQ. I am a computer scientist by profession and deeply skeptical of paranormal claims (although I may include some pro-paranormal arguments here). If anyone else with a less skeptical point of view wants to start a FAQ list, please feel free. I certainly can't stop you. Disclaimer: The opinions in this article are not necessarily those of GEC. Other Topics ============ Please send in contact addresses for local skeptics organisations not listed in section 0.11. Credits ======= Thanks to all the people who have sent me submissions and comments. There isn't enough room to thank everyone individually, but some of the more major contributors are listed here: York H. Dobyns <ydobyns@phoenix.Princeton.EDU> provided carbon 14 dating information, notes about current psi researchers and other useful comments. Dendrochronology information came from <whheydt@pbhya.PacBell.com>. The questions "What are UFOs?" and "Are crop circles made by flying saucers?" were answered by Chris Rutkowski <rutkows@ccu.umanitoba.ca> Ken Shirriff <shirriff@sprite.Berkeley.EDU> provided information on perpetual motion machines, Leidenfrost reference and the AIDS section. Robert Sheaffer <sheaffer@netcom.com> sent information about Philip Klass and UFO abductions. The Ezekiel information comes from a posting by John Baskette <jfb@draco.macsch.com>. John Boyd <jboyd@uk.ac.ed> provided skeptical references on acupuncture. Eric Raymond <esr@snark.thyrsus.com> contributed an explanation of the "paranormalist" point of view for item 0.7, along with information on acupuncture, the origin of life, and the CIA AIDS theory. Kirlian photography information was paraphrased from an article by Dave Palmer <dpalmer@csulb.edu>. Cold reading information came from an article by Pope Charles <popec@brewich.hou.tx.us>. Todd Stark <tark@com.dec.ENET.dwovax> sent information on acupuncture analgesia. Geoff Lane <zzassgl@uk.ac.manchester-computing-centre.uts> provided the article and references on Tunguska. Contents ======== A `*' indicates a new or rewritten entry. A `+' indicates an altered entry. Background ---------- 0.1: What is sci.skeptic for? 0.2: What is sci.skeptic not for? 0.3: What is CSICOP? Whats their address? 0.4: What is "Prometheus"? 0.5: Who are some prominent skeptics? + 0.6: Aren't all skeptics just closed-minded bigots? 0.6.1: Why are skeptics so keen to rubbish fringe ideas? * 0.6.2: How do we know Randi is honest? * 0.7: Aren't all paranormalists just woolly-minded fools? 0.7.1: Why don't skeptics challenge religions? * 0.8: What is a "conspiracy theory"? 0.9: What is "cold reading?" 0.10: Is there a list of logical fallacies? 0.11: What local skeptics organisations are there? * The Scientific Method --------------------- 1.1: What is the scientific method? 1.2: What is the difference between a fact, a theory and a hypothesis? + 1.3: Can science ever really prove anything? 1.4: If scientific theories keep changing, where is the Truth? 1.5: What evidence is needed for an extraordinary claim? 1.6: What is Occam's Razor? 1.7: Galileo was persecuted, just like researchers into <X> today. 1.8: What is the "Experimenter effect". 1.9: How much fraud is there in science? 1.9.1: Did Mendel fudge his results? Psychic Powers -------------- 2.1: Is Uri Geller for real? 2.2: I have had a psychic experience. 2.3: What is "sensory leakage"? 2.4: Who are the main psi researchers? 2.5: Does dowsing work? 2.6: Could psi be inhibited by the presence of skeptics? 2.7: Why don't the skeptics test the *real* psychics? UFOs/Flying Saucers ------------------- 3.1 What are UFOs? 3.1.1: Are UFOs alien spacecraft? 3.1.2: Are UFOs natural phenomena? 3.1.3: But isn't it possible that aliens are visiting Earth? 3.2: Is it true that the US government has a crashed flying saucer? (MJ-12)? 3.3: What is "channeling"? 3.4: How can we test a channeller? 3.5: I am in telepathic contact with the aliens. 3.6: Some bozo has just posted a load of "teachings" from a UFO. What should I do? 3.7: Are crop circles made by flying saucers? 3.7.1: Are crop circles made by "vortices"? 3.7.2: Are crop circles made by hoaxers? 3.7.3: Are crop circles radioactive? 3.7.4: What about cellular changes in plants within crop circles? 3.8: Have people been abducted by UFOs? 3.9: What is causing the strange cattle deaths? 3.10: What is the face on Mars? 3.11: Did Ezekiel See a Flying Saucer? 3.12: What happened at Tunguska? Faith Healing and Alternative Therapies --------------------------------------- 4.1: Isn't western medicine reductionistic and alternatives holistic? 4.2: What is a double-blind trial? What is a placebo? 4.3: Why should scientific criteria apply to alternative therapies? 4.4: What is homeopathy? 4.5: What is aromatherapy? 4.6: What is reflexology? 4.7: Does acupuncture work? 4.8: What about psychic surgery? 4.9: What is Crystal Healing? 4.10: Does religious healing work? 4.11: What harm does it do anyway? Creation versus Evolution ------------------------- 5.1: Is the Bible evidence of anything? 5.2: Could the Universe have been created old? 5.3: What about Carbon-14 dating? 5.4: What is "dendrochronology"? 5.5: What is evolution? Where do I find out more? 5.6: "The second law of thermodynamics says...." 5.7: How could living organisms arise "by chance"? 5.8: But doesn't the human body seem to be well designed? 5.9: What about the thousands of scientists who have become Creationists? 5.10: Is the speed of light decreasing? 5.11: What about Velikovsky? Fire-walking ----------- 6.1: Is fire-walking possible? 6.2: Can science explain fire-walking? New Age ------- 7.1: What do New Agers believe? 7.2: What is the Gaia hypothesis? 7.3: Was Nostradamus a prophet? + 7.4: Does astrology work? 7.4.1: Could astrology work by gravity? 7.4.2: What is the `Mars Effect'? 7.5: What is Kirlian photography? Strange Machines: Free Energy and Anti-Gravity ---------------------------------------------- 8.1: Why don't electrical perpetul motion machines work? 8.2: Why don't magnetic perpetual motion machines work? 8.3: Why don't mechanical perpetual motion machines work? 8.4: Magnets can levitate. Where is the energy from? 8.5: But its been patented! 8.6: The oil companies are conspiring to suppress my invention! 8.7: My machine gets its free energy from <X> 8.8: Can gyroscopes neutralise gravity? 8.9: My prototype gets lighter when I turn it on AIDS ---- 9.1: What about these theories on AIDS? 9.1.1: The Mainstream Theory 9.1.2: Strecker's CIA Theory 9.1.3: Duesberg's Risk-Group Theory ---------------------------------------------------------------------- Background ========== 0.1: What is sci.skeptic for? ----------------------------- [Did anyone save the Charter? PAJ] Sci.skeptic is for those who are skeptical about claims of the paranormal to meet with those who believe in the paranormal. In this way the paranormalists can expose their ideas to scientific scrutiny, and if there is anything in these ideas then the skeptics might learn something. However this is a very wide area, and some of the topics covered might be better kept in their own newsgroups. In particular the evolution vs. creation debate is best kept in talk.origins. General New Age discussions belong in talk.religion.newage. Strange "Heard it on the grapevine" stories belong on alt.folklore.urban, which discusses such things as vanishing hitchhikers and the Everlasting Lightbulb conspiracy. Serious conspiracy theories should be kept on alt.conspiracy, and theories about the assassination of President Kennedy should be kept on alt.conspiracy.jfk. CROSS-POSTING from these groups is NOT APPRECIATED by the majority of sci.skeptic readers. The discussion of a topic in this FAQ is not an attempt to have the final word on the subject. It is simply intended to answer a few common questions and provide a basis for discussion of common topics. 0.2: What is sci.skeptic not for? --------------------------------- The scope of sci.skeptic extends into any area where hard evidence can be obtained, but does not extend into speculation. So religious arguments about the existence of God are out of place here (take them to alt.atheism or talk.religion.*). On the other hand discussion about miracles is to be welcomed, since this is an issue where evidence can be obtained. Topics that have their own groups should be taken to the appropriate group. See the previous answer for a partial list. Also out of place are channelled messages from aliens. If your channelled message contains testable facts then post those. Otherwise we are simply not interested. Take it to alt.alien.visitors. The posting of large articles (>200 lines) is not a way to persuade people. See the section on "closed minded skeptics" below for some reasons for this. I suggest you summarise the article and offer to mail copies to anyone who is interested. Sci.skeptic is not an abuse group. There is a regrettable tendency for polite discussion here to degenerate into ad-hominem flames about who said what to whom and what they meant. PLEASE DO NOT FLAME. You won't convince anyone. Rather the opposite. 0.3: What is CSICOP? What is its address? ------------------------------------------ CSICOP stands for the "Committee for the Scientific Investigation of Claims Of the Paranormal". They publish a quarterly magazine called "The Skeptical Inquirer". Their address is: Skeptical Inquirer, Box 703, Buffalo, NY 14226-9973. Tel. 716-636-1425 voice, 716-636-1733 fax. Note that this is a new address. 0.4: What is "Prometheus"? -------------------------- Prometheus Books is a publisher specialising in skeptical books. Their address is: Prometheus Books 700 Amherst Street Buffalo, NY 14215-9918 0.5: Who are some prominent skeptics? ------------------------------------- James "The Amazing" Randi is a professional stage magician who spends much time and money debunking paranormal claims. He used to offer a reward of $100,000 to anyone who can demonstrate paranormal powers under controlled conditions, but has had to exhaust that fund to pay legal expenses in the series of lawsuits that have been brought against him since 1988. Currently, he can offer only a $10,000 promissory note. Anyone who wants to contribute to his defense can do so via: The James Randi Fund c/o Robert Steiner, CPA P.O. Box 659 El Cerrito, CA 94530 The lawsuit by Geller against Randi is still going on. There is a mailing list for updates on the situation, which originates from the account <geller-hotline@ssr.com>. [To subscribe, you should probably send mail to <geller-hotline-request@ssr.com>.] Martin Gardner is an author, mathematician and amateur stage magician who has written several books dealing with paranormal phenomena, including "Science: Good, Bad and Bogus" and "Fads and Fallacies in the Name of Science". Philip J. Klass retired after thirty-five years as a Senior Editor of "Aviation Week and Space Technology" magazine, specializing in avionics. He is a founding fellow of CSICOP, and was named a Fellow of the Institute of Electrical and Electronics Engineers (IEEE). He has won numerous awards for his technical journalism. His principal books are: UFO Abductions, A Dangerous Game (Prometheus, 1988) UFOs, The Public Deceived (Prometheus, 1983) UFOs Explained (Random House, 1974) Susan Blackmore holds a Ph.D in parapsychology, but in the course of her Ph.D research she became increasingly disillusioned and is now highly skeptical of paranormal claims. Ray Hyman is a professor of psychology at the University of Oregon. He is one of the major external, skeptical critics of parapsychology. In 1986, he and parapsychologist Charles Honorton engaged in a detailed exchange about Honorton's ganzfeld experiments and statistical analysis of his results which was published in the Journal of Parapsychology. A collection of Hyman's work may be found in his book The Elusive Quarry: A Scientific Appraisal of Psychical Research, 1989, Prometheus. This includes "Proper Criticism", an influential piece on how skeptics should engage in criticism, and "'Cold Reading': How to Convince Strangers that You Know All About Them." James Alcock is a professor of psychology at York University in Toronto. He is the author of the books Parapsychology: Science or Magic?, 1981, Pergamon, and Science and Supernature: A Critical Appraisal of Parapsychology, 1990, Prometheus. Joe Nickell is a former private investigator, a magician, and an English instructor at the University of Kentucky. He is the author of numerous books on paranormal subjects, including Inquest on the Shroud of Turin, 1982, Prometheus. He specializes in investigating individual cases in great detail, but has recently done some more general work, critiquing crop circles, spontaneous human combustion, and psychic detectives. Isaac Asimov wrote a great deal on skeptical issues. He had a regular column in _Fantasy and Science Fiction_, and collections of essays from it have been published. Some of these essays are on assorted crackpottery, like UFO's, Velikovsky, creationism, and so forth. They have titles like "Worlds in Confusion" (Velikovsky), "Look Long upon a Monkey" (creationism), "Armies of the Night" (crackpottery in general), "The Rocketing Dutchmen" (UFO's), and so forth.; these are usually on a rather general sort of level. Marcello Truzzi was one of the founders of CSICOP, but broke away from the organisation when it became to "dry" for him (see section 0.6.1 on wet vs. dry skeptics). He now publishes the "Zetetic Inquirer" on an occasional basis. He can be contacted at the Dept. of Sociology, Eastern Michigan University, Ypsilanti, MI 48197, or at P.O. Box 1052, Ann Arbor, MI 48106. [Does anyone know if this address is still good? PAJ] [Can someone supply me with potted biographies and publication lists of these and other people? PAJ] 0.6: Aren't all skeptics just closed-minded bigots? --------------------------------------------------- People who have failed to convince skeptics often say "Well all skeptics are just closed-minded bigots who won't listen to me!". This is not true. Skeptics pay close attention to the evidence. If you have no evidence then you will get nowhere. Unfortunately life is short. Most of us have better things to do than investigate yet another bogus claim. Some paranormal topics, especially psi research and UFOlogy, produce vast quantities of low grade evidence. In the past people have investigated such evidence carefully, but it always seems to evaporate when anyone looks at it closely. Hence skeptics should be forgiven for not bothering to investigate yet another piece of low grade evidence before rejecting it. Issac Asimov has suggested a triage process which divides scientific claims into three groups: mundane, unusual and bullshit [my terms]. As an example, a claim that "I have 10kg of salt in my lab" is pretty mundane. No-one would disbelieve me, but they wouldn't be very interested. A claim that "I have 10kg of gold in my lab" would probably result in mild disbelief and requests to have a look. Finally a claim that "I have 10kg of Einsteinium in my lab" would be greeted with cries of "Bullshit!". Of course there are some who substitute flaming and rhetoric for logical argument. We all lose our temper sometimes. 0.6.1: Why are skeptics so keen to rubbish fringe ideas? -------------------------------------------------------- Skeptics vary on the attitude they take towards a new fringe idea, varying from the "wet" to the "dry". The question of which attitude is better is very much a live issue in the skeptical community. Here is a brief summary of the two extremes: DRY: There is no reason to treat these people seriously. Anyone with half an ounce of sense can see that their ideas are completely bogus. Time spent trying to "understand their ideas" and "examine their evidence" beyond that necessary for debunking is wasted time, and life is short. Furthermore, such behaviour lends them respectibility. If we take them seriously, so will other people. We must ridicule their ideas so that others will see how silly they are. "One belly laugh is worth a thousand syllogisms" (Martin Gardner). WET: If we lay into these people without giving them a fair hearing then we run two risks: 1: We might miss someone who is actually right. History contains many examples. 2: We give them a weapon against us. Ad-hominem attacks and sloppy logic bring us down to their level. If we are truly the rational, scientific people we claim to be then we should ask for their evidence, and then pronounce our considered opinion of it. The two extremes are perhaps personified by Martin Gardner (dry) and Marcello Truzzi (wet). Note that no particular judgement is attached to these terms. They are just handy labels. People who read articles by dry skeptics often get the impression that skeptics are as pig-headed as any fundamentalist or stage psychic. I think that this is a valid criticism of some skeptics on the dry end. However, an article which ridicules fringe beliefs may also contain sound logic based on careful investigation. As always, you have to read carefully, distinguish logic from rhetoric, and then make a judgement. 0.6.2: How do we know Randi is honest? -------------------------------------- Randi has offered a large prize to anyone who can demonstrate paranormal powers under controlled conditions. He also has a lot of professional prestige tied up in his self-appointed role of psychic debunker. This leads to allegations that if he ever did find a genuine psychic then he would lie rather than lose so much money and prestige. When Randi tests psychic claims, he is always very careful to agree with the claimant before the test exactly what the conditions will be. The test will proceed only if both he and the claimant agree that this will be a fair test of the claim. The conditions usually involve video tapes and independant witnesses specifically to rule out cheating by either side. On one occasion Randi did agree that the claimant had passed the test. Arthur G. Lintgen claimed an ability to identify LP records without labels. Randi tested him, and found that he could in fact do this by reading the patterns of loud and quiet in the groove. Lintgen did not get Randi's reward because he had not demonstrated (or claimed) any paranormal ability. 0.7: Aren't all paranormalists just woolly-minded fools? -------------------------------------------------------- [The following was contributed by Eric Raymond <esr@snark.thyrsus.com>] Some `paranormalists' are people who fully agree with the scientific method and scientific cosmology, but who are also trying to deal with personal experiences or abilities that do not presently seem to fit accepted scientific theory. The honest skeptic should recognize that not all paranormalists are supernaturalists. The honest skeptic should also recognize that some phenomena formerly thought of as `paranormal' are now within the purview of science. The classic example is meteorites; more recent ones include the remarkable somatic-control abilities of advanced yogis, the physiological mechanisms behind acupuncture and acupressure, and healing by laying on of hands (now widely taught in mainstream nursing schools as `therapeutic touch'). To assume uncritically that all paranormalists are simply flakes risks foreclosing future advances of the same kind. And there may be some doozies waiting in the wings. Recent experiments in computer analysis of EEG/EMG patterns, for example, strongly suggest that mental telepathy is at least *possible in principle* between speakers of the same language (though it has not been demonstrated to occur). Thus, the honest skeptic owes it to him/herself to remember that the flakiness and credulity of *some* paranormalists does not imply the insanity of *all*. 0.7.1: Why don't skeptics debunk religions? ------------------------------------------- Skeptics aim to debunk false claims and silly theories by using the *evidence*. The question of whether God exists is not one for which evidence is available, and so skeptics tend to treat it as a private matter. When someone claims to have evidence (such as a miraculous healing) then skeptics are as ready to test this claim as they are any other. Most skeptics agree that it is perfectly possible to be a skeptic about paranormal claims but still honestly believe in God. Martin Gardner is a "dry" skeptic and one of the founders of CSICOP. He also believes in a personal god and describes himself as a "philosophical theist". Most skeptics tend to take an "agnostic-atheist" attitude, assuming that God does not exist until evidence to the contrary turns up. If you are interested in organisations that oppose religion in general then see the alt.atheism FAQ "Atheist Resources" for a list of atheist and humanist organisations. 0.8: What is a Conspiracy Theory? --------------------------------- There are two general categories of conspiracy theory: Grand and Petty. A Grand conspiracy theory is a belief that there is a large-scale conspiracy by those in power to mislead and/or control the rest of the world. Consider the following example: There is a conspiracy amongst the computer programmers to control the world. They are only allowing the public to have simple machines, while they control the really powerful ones. There is a computer in <city> they call "The Beast". It has records about everyone. They use this information to manipulate the politicians and businessmen who ostensibly rule the world into doing their will. The Beast was prophesied in the Book of Revelation. Grand conspiracy theories divide the world into three groups. The Conspirators, the Investigators, and the Dupes. Conspirators have a vast secret. The Investigators have revealed parts of the conspiracy, but much is still secret. Investigators are always in great danger of being silenced by Conspirators. Dupes are just the rest of us. Often the Conspirators show a mixture of incredible subtlety and stunning stupidity. Evidence produced by the Investigators is always either circumstantial or evaporates when looked at carefully. The theories can never be disproved, since any evidence to the contrary can be dismissed as having been planted by the Conspirators. If you spend any time or effort digging into the evidence produced by Investigators then you will be labelled a Conspirator yourself. Of course, nothing a Conspirator says can be believed. Petty conspiracy theories are smaller than the Grand variety, and sometimes turn out to be true. Watergate and "Arms for Hostages" episodes both started life as Petty conspiracy theories. Just because a theory involves a conspiracy does not make that theory false. The main difference between Grand and Petty Conspiracy Theories is the number of alleged conspirators. Grand Conspiracy Theories require thousands or even millions. [Since this FAQ was first posted I have heard that the Beast computer is in Holland and that you can be saved by converting to a particular cult. In addition the cult claims that every product bar code includes three 6 digits as frame markers, hence 666, the number of the beast. In fact this is not true, and even if it were it would not fulfill the prophecy in Revelation. Meanwhile the cult members were *meant* to rise up to heaven on 29/10/92 but very embarrassingly didn't. The Korean founder was also discovered to have bought millions of $ worth of stocks and bonds which didn't mature until 1995, and was convicted of fraud.] 0.9: What is "cold reading"? ---------------------------- [From a posting by Pope Charles <popec@brewich.hou.tx.us>] Cold reading is the technique of saying little general things and watching a persons reactions. As one goes from very general to more specific things, one notes the reaction and uses it as a giude ti find out what to say. Also there are stock phrases that sound like statements but are really questions. If these subtle questions evoke answers, these answers are used as a basis for the next round of statements. Many people get involved in various things like this because of their interest in the usual things, health, love, sex, ect. One can develope a set of stock questions and statements that will elicit positive responses fom 90% of your 'clients'. In the hands of an expert, these simple techniques can be frightening almost. But they are simple things. Of course a paintbrush and a canvass are simple things too. It all depends on skill and talent for these things. One can learn these things coldbloodedly knowing them as the tricks they are, or as probably most use them, learned at the feet of other practitioners as it were by rote, and developed by practice and adapted to the tastes of the reader and his or her sitters. As skeptics have pointed out, it is the best cold readers that make the best Tarot Readers, Astrologers, Palm Readers, or what have you. If your library is lucky enough to have it, Check The Zetetic, (later renamed Skeptical Inquirer), Vol. 1, #2 Summer 1977 "Cold Reading: How to convince strangers you know all about them" by Ray Hyman. These techniques are not confined to the occult world by any means. Religous workers, salesmen and the like use the principles to build rapport with people. 0.10: Is there a list of logical fallacies? ------------------------------------------- A complete list of formal and informal logical fallacies is posted by Mathew <mathew@mantis.com> as part of his excellent alt.atheism FAQ file series. This should be read carefully by anyone wishing to construct a logical argument to support their position on any group. For those who want more information, "The Book of the Fallacy" by Madsen Pirie covers the same ground in more detail. Formal and informal statistical fallacies are dealt with in the book "How To Lie With Statistics" by Darrell Huff. I strongly recommend this one. 0.11: What local skeptics organisations are there? -------------------------------------------------- [Contact addresses please] Australian Skeptics "The Skeptic", P.O. Box 475, PO Box E324 Manchester, St. James M60 2TH, Sydney U.K. NSW 2000 The Scientific Method ===================== 1.1: What is the "scientific method"? ------------------------------------- The scientific method is the best way yet discovered for winnowing the truth from lies and delusion. The simple version looks something like this: 1: Observe some aspect of the universe. 2: Invent a theory that is consistent with what you have observed. 3: Use the theory to make predictions. 4: Test those predictions by experiments or further observations. 5: Modify the theory in the light of your results. 6: Go to step 3. This leaves out the co-operation between scientists in building theories, and the fact that it is impossible for every scientist to independently do every experiment to confirm every theory. Because life is short, scientists have to trust other scientists. So a scientist who claims to have done an experiment and obtained certain results will usually be believed, and most people will not bother to repeat the experiment. Experiments do get repeated as part of other experiments. Most scientific papers contain suggestions for other scientists to follow up. Usually the first step in doing this is to repeat the earlier work. So if a theory is the starting point for a significant amount of work then the initial experiments will get replicated a number of times. Some people talk about "Kuhnian paradigm shifts". This refers to the observed pattern of the slow extension of scientific knowledge with occasional sudden revolutions. This does happen, but it still follows the steps above. Many philosophers of science would argue that there is no such thing as *the* scientific method. 1.2: What is the difference between a fact, a theory and a hypothesis? ---------------------------------------------------------------------- In popular usage, a theory is just a vague and fuzzy sort of fact. But to a scientist a theory is a conceptual framework that *explains* existing facts and predicts new ones. For instance, today I saw the Sun rise. This is a fact. This fact is explained by the theory that the Earth is round and spins on its axis while orbiting the sun. This theory also explains other facts, such as the seasons and the phases of the moon, and allows me to make predictions about what will happen tomorrow. This means that in some ways the words "fact" and "theory" are interchangeable. The organisation of the solar system, which I used as a simple example of a theory, is normally considered to be a fact that is explained by Newton's theory of gravity. And so on. A hypothesis is a tentative theory that has not yet been tested. Typically, a scientist devises a hypothesis and then sees if it "holds water" by testing it against available data. If the hypothesis does hold water, the scientist declares it to be a theory. 1.3: Can science ever really prove anything? -------------------------------------------- Yes and no. It depends on what you mean by "prove". For instance, there is little doubt that an object thrown into the air will come back down (ignoring spacecraft for the moment). One could make a scientific observation that "Things fall down". I am about to throw a stone into the air. I use my observation of past events to predict that the stone will come back down. Wow - it did! But next time I throw a stone, it might not come down. It might hover, or go shooting off upwards. So not even this simple fact has been really proved. But you would have to be very perverse to claim that the next thrown stone will not come back down. So for ordinary everyday use, we can say that the theory is true. You can think of facts and theories (not just scientific ones, but ordinary everyday ones) as being on a scale of certainty. Up at the top end we have facts like "things fall down". Down at the bottom we have "the Earth is flat". In the middle we have "I will die of heart disease". Some scientific theories are nearer the top than others, but none of them ever actually reach it. Skepticism is usually directed at claims that contradict facts and theories that are very near the top of the scale. If you want to discuss ideas nearer the middle of the scale (that is, things about which there is real debate in the scientific community) then you would be better off asking on the appropriate specialist group. 1.4: If scientific theories keep changing, where is the Truth? -------------------------------------------------------------- In 1666 Isaac Newton proposed his theory of gravitation. This was one of the greatest intellectual feats of all time. The theory explained all the observed facts, and made predictions that were later tested and found to be correct within the accuracy of the instruments being used. As far as anyone could see, Newton's theory was the Truth. During the nineteenth century, more accurate instruments were used to test Newton's theory, and found some slight discrepancies (for instance, the orbit of Mercury wasn't quite right). Albert Einstein proposed his theories of Relativity, which explained the newly observed facts and made more predictions. Those predictions have now been tested and found to be correct within the accuracy of the instruments being used. As far as anyone can see, Einstein's theory is the Truth. So how can the Truth change? Well the answer is that it hasn't. The Universe is still the same as it ever was, and Newton's theory is as true as it ever was. If you take a course in physics today, you will be taught Newton's Laws. They can be used to make predictions, and those predictions are still correct. Only if you are dealing with things that move close to the speed of light do you need to use Einstein's theories. If you are working at ordinary speeds outside of very strong gravitational fields and use Einstein, you will get (almost) exactly the same answer as you would with Newton. It just takes longer because using Einstein involves rather more maths. One other note about truth: science does not make moral judgements. Anyone who tries to draw moral lessons from the laws of nature is on very dangerous ground. Evolution in particular seems to suffer from this. At one time or another it seems to have been used to justify Nazism, Communism, and every other -ism in between. These justifications are all completely bogus. Similarly, anyone who says "evolution theory is evil because it is used to support Communism" (or any other -ism) has also strayed from the path of Logic. 1.5: What evidence is needed for an extraordinary claim? -------------------------------------------------------- Extraordinary evidence. An extraordinary claim is one that contradicts a fact that is close to the top of the certainty scale discussed above. So if you are trying to contradict such a fact, you had better have facts available that are even higher up the certainty scale. 1.6: What is Occam's Razor? --------------------------- Ockham's Razor ("Occam" is a Latinised variant) is the principle proposed by William of Ockham in the fifteenth century that "Pluralitas non est ponenda sine neccesitate", which translates as "entities should not be multiplied unnecessarily". Various other rephrasings have been incorrectly attributed to him. In more modern terms, if you have two theories which both explain the observed facts then you should use the simplest until more evidence comes along. See W.M. Thorburn, "The Myth of Occam's Razor," _Mind_ 27:345-353 (1918) for a detailed study of what Ockham actually wrote and what others wrote after him. The reason behind the razor is that for any given set of facts there are an infinite number of theories that could explain them. For instance, if you have a graph with four points in a line then the simplest theory that explains them is a linear relationship, but you can draw an infinite number of different curves that all pass through the four points. There is no evidence that the straight line is the right one, but it is the simplest possible solution. So you might as well use it until someone comes along with a point off the straight line. Also, if you have a few thousand points on the line and someone suggests that there is a point that is off the line, it's a pretty fair bet that they are wrong. A related rule, which can be used to slice open conspiracy theories, is Hanlon's Razor: "Never attribute to malice that which can be adequately explained by stupidity". See the Jargon File (edited by Eric Raymond) for more details. 1.7: Galileo was persecuted, just like researchers into <X> today. ------------------------------------------------------------------ People putting forward extraordinary claims often refer to Galileo as an example of a great genius being persecuted by the establishment for heretical theories. They claim that the scientific establishment is afraid of being proved wrong, and hence is trying to suppress the truth. This is a classic conspiracy theory. The Conspirators are all those scientists who have bothered to point out flaws in the claims put forward by the researchers. The usual rejoinder to someone who says "They laughed at Columbus, they laughed at Galileo" is to say "And they also laughed at Bozo the Clown". (From Carl Sagan, "Broca's Brain", Coronet 1980, p79). Incidentally, stories about the persecution of Galileo Galilei and the ridicule Christopher Columbus had to endure should be taken with a grain of salt. During the early days of Galileo's theory church officials were interested and sometimes supportive, even though they had yet to find a way to incorporate it into theology. His main adversaries were established scientists - since he was unable to provide HARD proofs they didn't accept his model. Galileo became more agitated, declared them ignorant fools and publicy stated that his model was the correct one, thus coming in conflict with the church. When Columbus proposed to take the "Western Route" the spherical nature of the Earth was common knowledge, even though the diameter was still debatable. Columbus simply believed that the Earth was a lot smaller, while his adversaries claimed that the Western Route would be too long. If America hadn't been in his way, he most likely would have failed. The myth that "he was laughed at for believing that the Earth was a globe" steems from an American author who intentionally adulterated history. 1.8: What is the "Experimenter effect"? --------------------------------------- It is unconscious bias introduced into an experiment by the experimenter. It can occur in one of two ways: o Scientists doing experiments often have to look for small effects or differences between the things being experimented on. o Experiments require many samples to be treated in exactly the same way in order to get consistent results. Note that neither of these sources of bias require deliberate fraud. A classic example of the first kind of bias was the "N-ray", discovered early this century. Detecting them required the investigator to look for very faint flashes of light on a scintillator. Many scientists reported detecting these rays. They were fooling themselves. A classic example of the second kind of bias were the detailed investigations into the relationship between race and brain capacity in the last century. Skull capacity was measured by filling the empty skull with beans and then measuring the volume of beans. A significant difference in the results could be obtained by ensuring that the beans in some skulls were better settled than others. For more details on this story, read Stephen Jay Gould's "The Mismeasure of Man". For more detail see: T.X. Barber, "Pitfalls of Human Research", 1976. Robert Rosenthal, "Pygmalion in the Classroom". [These were recommended by a correspondant. Sorry I have no more information.] 1.9: How much fraud is there in science? ---------------------------------------- In its simplest form this question is unanswerable, since undetected fraud is by definition unmeasurable. Of course there are many known cases of fraud in science. Some use this to argue that all scientific findings (especially those they dislike) are worthless. This ignores the replication of results which is routinely undertaken by scientists. Any important result will be replicated many times by many different people. So an assertion that (for instance) scientists are lying about carbon-14 dating requires that a great many scientists are engaging in a conspiracy. See the previous question. In fact the existence of known and documented fraud is a good illustration of the self-correcting nature of science. It does not matter if a proportion of scientists are fraudsters because any important work they do will not be taken seriously without independant verification. Hence they must confine themselves to pedestrian work which no-one is much interested in, and obtain only the expected results. For anyone with the talent and ambition necessary to get a Ph.D this is not going to be an enjoyable career. Also, most scientists are idealists. They perceive beauty in scientific truth and see its discovery as their vocation. Without this most would have gone into something more lucrative. These arguments suggest that undetected fraud in science is both rare and unimportant. For more detail on more scientific frauds than you ever knew existed, see "False Prophets" by Alexander Koln. 1.9.1: Did Mendel fudge his results? ------------------------------------ Gregor Mendel was a 19th Century monk who discovered the laws of inheritance (dominant and recessive genes etc.). More recent analysis of his results suggest that they are "too good to be true". Mendelian inheritance involves the random selection of possible traits from parents, with particular probabilities of particular traits. It seems from Mendel's raw data that chance played a smaller part in his experiments than it should. This does not imply fraud on the part of Mendel. First, the experiments were not "blind" (see the questions about double blind experiments and the experimenter effect). Deciding whether a particular pea is wrinkled or not needs judgement, and this could bias Mendel's results towards the expected. This is an example of the "experimenter effect". Second, Mendel's Laws are only approximations. In fact it does turn out that in some cases inheritance is less random than his Laws state. Third, Mendel might have neglected to publish the results of `failed' experiments. It is interesting to note that all of his published work is concerned with characteristics which are controlled by single genes. He did not report any experiments with more complicated characteristics. Psychic Powers ============== 2.1: Is Uri Geller for real? ---------------------------- James "The Amazing" Randi has, through various demonstrations, cast doubt on Geller's claims of psychic powers. Geller has sued Randi. Skeptics are advised to exercise extreme caution in addressing this topic, given the pending litigation. Bay Area Skeptics, Tampa Bay Skeptics, and the Skeptics Society of Los Angeles have all been threatened with litigation over this matter, which could be expected to be extremely expensive and time-consuming whatever the eventual outcome. 2.2: I have had a psychic experience. ------------------------------------- That is pretty remarkable. But before you post to the Net, consider:- * Could it just be coincidence? The human mind is good at remembering odd things but tends to forget ordinary things, such as premonitions that didn't happen. If psychic experiences happen to you on a regular basis then try writing down the premonitions when you have them and then comparing your record to later events. * If you think you have a mental link with someone you know, try a few tests with playing cards [Has anyone got a good protocol for this kind of thing? PAJ]. * If you are receiving messages from elsewhere (e.g. UFOs), ask for specific information that you can then check. The complete prime factorisation of 2^1024+1 would be a good start: we don't know it, but any proposed answer is easy to check. If you want to make a formal registration of your predictions, send mail to <prediction_registry@sol1.gps.caltech.edu>. 2.3: What is "Sensory Leakage"? ------------------------------- Sensory leakage is something that designers of tests for psi must be careful to guard against. Tests for psi use powerful statistical tests to search for faint traces of communication. Unfortunately the fact that communication has taken place does not prove that it was done by telepathy. It could have been through some more mundane form of signal. For instance one experiment involved a "sender" in one room with a stack of numbered cards (1-10) and a "receiver" in another room trying to guess what the next card was. The sender looked at a card and pressed a button to signal to the receiver. The receiver then tried to guess the number on the card. There was a definite correlation between the card numbers and the guesses. However the sender could signal the receiver by varying the delays between buzzes. When this channel of communication was removed, the effect disappeared. 2.4: Who are the main psi researchers? -------------------------------------- Targ and Puthoff spring to mind, but actually, Puthoff is no longer doing psi research (I don't have any idea what Targ is up to these days.) Granted, their SRI work is quite famous, but if we want to review the historical (rather than currently active) figures, you probably want to go back at least as far as the Rhines. Helmut Schmidt, a physicist who has been looking at PK, is still active at the Mind Science Foundation in Texas. (Sorry, I don't know a more specific address than that.) The Foundation for Research into the Nature of Man (FRNM), which is what Rhine's work at Duke eventually developed into, is still active near Duke. It is currently headed by K. Ramakrishna Rao. The Koestler Chair of Parapsychology at the University of Edinburgh is, as far as I know, still active. The current incumbent is, I think, named Robert Morris; his main assistant is Deborah Delanoy. Roger Nelson is active in the Princeton Engineering Anomalies Research center (PEAR) and occasionally posts to the net. Active workers in the field that I can think of currently include Dean Radin, who also posts to sci.skeptic as <dir2@gte.com>, Jessica Utts, and Ed May. The Parapsychological Association has a much larger roster than that, of course, but I'm not a member myself and don't have access to their membership roll. 2.5: Does dowsing work? ----------------------- Dowsing is the art of finding underground water by extra-sensory perception. Sometimes tools are used. The traditional one is a forked hazel stick. When held in the correct way this will twitch in response to small muscle movements in the back and shoulders. Another tool that has become popular in recent years is a pair of rods mounted in tubes that are held in each hand just in front of the user. Rod bent into tube. | V r------------------------------- || ^ || | || <- Tube Rod || || || When water (or something else) is dowsed, the rods turn towards each other. Like the forked hazel stick it amplifies small movements of the arm and shoulder muscles. Unfortunately careful tests of dowsers have revealed absolutely no ability to find water or anything else by extra-sensory perception. Dowsing success stories can be explained by noting that wherever you dig you will find water. You just have to dig deep enough. It has also been suggested that dowsers may unconsciously use clues in the environment. James Randi has tested more than 100 dowsers (I don't know the actual count). He tells that only 2 tried to cheat. This suggests that dowsers are basically honest people. The Skeptical Inquirer has published a number of articles on dowsing. James Randi's "A Controlled Test of Dowsing" was in vol. 4, no. 1, pp. 16-20. Michael Martin's "A New Controlled Dowsing Experiment" was in vol. 8, pp. 138-140. Dick Smith's "Two Tests of Divining in Australia" was in vol. 6, no. 4, pp. 34-37. Randi's book Flim-Flam! has a section on dowsing. The main skeptical book about dowsing is Vogt, E.Z. and Hyman R. (1959, 2nd edition 1979) "Water witching USA". The University of Chicago Press. 260 pages. Available as a paperback. 2.6: Could psi be inhibited by the presence of skeptics? -------------------------------------------------------- Psychic researchers have noted something they call the "shyness effect" (or more grandly "psi-mediated experimenter effects"). This is invoked to explain the way in which many subjects' psychic powers seem to fade when exposed to careful scrutiny and proper controls. Often it is alleged that having a skeptic in the audience can prevent the delicate operation of psi. In its most extreme form this hypothesis becomes a "catch-22" that makes any results consistent with a psi hypothesis. This renders the hypothesis unfalsifiable and therefore unscientific. Less extreme forms might be testable. 2.7: Why don't the skeptics test the *real* psychics? ----------------------------------------------------- A claim is sometimes made that the Skeptics movement only tests those psychics which it knows to be frauds. The real psychics are supposedly being ignored by skeptics who are afraid to be proved wrong. There are three problems with this claim. Firstly, it assumes that all the skeptics are engaged in a conspiracy to persuade the world that psychic powers do not exist. This is only a Petty Conspiracy theory (see section 0), since it only requires the involvment of a few dozen of the most prominent skeptics, but it is still difficult to see any motive for such a deception. "Fear of being proved wrong" implies that they already know they are wrong, which makes their continued activity rather puzzling. Secondly, most skeptics are always ready to take part in any reasonable test. The "real" psychics are perfectly at liberty to challange the skeptics. Thirdly, there are always more alleged psychics. Hence this argument presents the skeptics with an ever-receeding target. The dialogue goes something like this: Paranormalist: Yes, I conceed that Mr. Adams is a fake, but what about Mr. Brown. The things that he does could never be faked. [Some months later] Skeptic: Here is how Brown did it.... P: OK, I conceed that Adams and Brown are fakes, but Mrs Carver is the surely the real thing. [Some months later] S: Here is how Carver did it... P: OK, maybe Adams, Brown and Carver were fakes, but what about Digby and Ender? S: I give up. There's no convincing some people. P: [shouting] Digby and Ender are real psychics: the skeptics are afraid to test them. They only test the fakes! UFOs and Flying Saucers ======================= 3.1 What are UFOs? ------------------- UFOs are, simply, Unidentified Flying Objects, no more, no less. This means that if you are out one night and see a light moving in the sky and cannot immediately identify it as a certain star, planet or other object, then it is by definition a UFO. THIS DOES NOT MEAN YOU HAVE SEEN AN ALIEN SPACESHIP. A better question would be: 3.1.1 Are UFOs alien spacecraft? --------------------------------- Probably not. The vast majority of UFO reports, when investigated by competent researchers (and that is a problem all by itself), can be easily explained as natural or manmade objects misidentified for one reason or another. The actual percentage is around 95%. A very few reports are provable hoaxes. The remaining few percent (some skeptics argue that there are no remaining reports) are not explained at this time. Again, this does not mean that they are observations of alien spaceships. All we can say is that, given the information presently available, some cases don't appear to be stars, balloons, airplanes, aurorae. etc. Given a great deal more time and effort, many more could likely be identified. It's possible that the witness(es) were in error, or are very good liars. And the remaining few cases? Well, the best we can say, as true skeptics, is that we don't know what they were, but there is NO proof that they were alien spacecraft. 3.1.2 Are UFOs natural phenomena? ---------------------------------- Possibly. A number of theories have been proposed, suggesting that some UFOs are "plasmas" or variations of ball lightning or earthquake lights. Unfortunately, the theories seem to change to fit observed data, rather than predict the observations. Also, studies designed to support the theories have used newspaper articles and raw, unsifted UFO case lists for data, and therefore the studies do not appear to be completely unbiased. Perhaps time will tell. Until then it is safe to say that SOME UFOs are probably ball lightning or other rare natural phenomena. 3.1.3 But isn't it possible that aliens are visiting Earth? ------------------------------------------------------------ Yes. But it is also possible that there is an invisible snorg reading this over your shoulder right now. Basically, some astronomers (e.g. Carl Sagan) are convinced that there are other habitable planets in our galaxy, and that there may be some form of life on them. Assuming that parallel evolution occurred on these other planets, there MIGHT be intelligent life forms there. It is possible that some of these life forms could have an advanced civilization, and perhaps have achieved space travel. BUT - there is no proof that this is so. SETI programs such as the High Resolution Microwave Search now being conducted by NASA under the direction of Jill Tartar are "listening" to other stars in the hope of detecting radio signals that might indicate intelligent life - kind of listening for the equivalent of "Watson, come here, I need you!", or "I love Lucy" in the infancy of our early communications. Such searches have been fruitless, so far. If there are aliens on distant planets, then it is possible that they might have found a way to travel between stars in their lifetimes. According to our present understanding of physics, this is not likely, given the vast distances between stars. Even travelling at the speed of light (which cannot be done), a round trip to the nearest star would take about ten years. This does not rule out interstellar ships, but it does make it seem unlikely that we are being visited. If *even one* civilization has found a way to travel between stars in the entire history of the Milky Way Galaxy (about ten billion years), it ought to fill the entire Galaxy in only a hundred million years or so. The question, then, is why don't we observe evidence of alien civilization everywhere? This question is known as the Fermi Paradox, and there is no really satisfactory answer. If, however, we postulate alien visits to Earth, we must also accept a Galaxy-wide civilization and ask why we see no evidence of it. 3.2: Is it true that the US government has a crashed flying saucer (MJ-12)? --------------------------------------------------------------------------- The MJ-12 documents purportedly established that the U.S. government had established a secret organization of 12 people called MJ-12 or Majestic-12 to deal with UFOs. These 12 people were all conveniently dead at the time the documents were discovered. Klass proved that the documents are fakes. The Roswell Incident refers to an alleged UFO crash in Roswell, NM. This is also known as the "Roswell Incident". Philip Klass has also investigated this one and shown the reports to be bogus. One of the more notable items of "evidence" was a document "signed by the president". Klass showed that this signature was a photocopy of an existing presidential signature. See SI 14:2 (Winter 1990) pp 135-140. All such allegations involve a conspiracy theory. Sometimes these conspiracy theories get very big indeed. One common one involves a treaty between the government and the saucer people whereby the government stays in power and the saucer people get to abduct humans for various gruesome purposes. 3.3: What is "channeling"? -------------------------- "Channeling" is remarkably similar to Spiritualism. The main difference is that the relatives "on the other side" are replaced by a wide variety of other beings. This means that the channeler does not have to worry about providing accurate information about people in the audience. The beings that channelers claim to speak for range from enlightened aliens to humans who lived thousands of years ago to discarnate intelligences who have never had bodies. 3.4: How can we test a channeler? --------------------------------- Some channelled entities are alleged to come from the distant past. They can be asked about events, climate and language in ways that can be checked. If the entity is from a technically advanced race, try asking for the complete factorisation of 2^1024+1. 3.5: I am in telepathic contact with the aliens. ------------------------------------------------ See the earlier section on psychic experiences and then try testing your aliens to see if you get a specific answer. If you can come up with new facts that can be tested by scientists then you will be listened to. Otherwise you would do better on alt.alien.visitors. 3.6: Some bozo has just posted a load of "teachings" from a UFO. What ---------------------------------------------------------------------- should I do? ------------ You have several choices: * Ignore it. * Ask for evidence (see question 3.4 above). * Insult or flame the poster. This is a bad idea. 3.7: Are crop circles made by flying saucers? --------------------------------------------- There is no convincing evidence that crop circles or any other kind of UGM (Unusual Ground Markings) were made by aliens. There are some reports of lights being seen in and around crop circle sites, and a few videos showing objects flitting over fields. The lights are hardly proof, and the objects in the videos seem to be pieces of foil or paper being tossed about by the wind. In a deliberate attempt to test crop circle "experts", a crop circle was faked under the watchful eyes of the media. When cerealogists were called in, they proclaimed it genuine. 3.7.1: Are crop circles made by "vortices"? --------------------------------------------- Probably not. There are a number of meteorologists who believe that crop circle formations are created by rare natural forces such as "ionised plasma vortices". Basically, winds blowing across rolling hills sometimes form eddies, which in some circumstances (that have never been quantified) become strong, downward spiralling drafts that lay down the crop. Cerealogists claim to have over two dozen witnesses to such events. Unfortunately, many more have said they have seen flying saucers do the same thing. Scientific articles arguing for the reality of these vortices have appeared regularly in the Journal of Meteorology. But its editor is the leading proponent of the theory, Dr. Terence Meaden. Winds can lay down crop in patches known as lodging. But geometric patterns in fields can hardly be attributable to natural phenomena. Meaden has changed his theory to first accommodate complex circles, ovals and even triangles (!), but now admits that most circles are hoaxes and the theory can only explain simpler patterns. 3.7.2: Are crop circles made by hoaxers? ----------------------------------------- Of course. Although most people have heard only of two, Doug Bower and Dave Chorley of England, many others have been caught, not only in Britain but in other countries such as Canada. Their methods range from inscribed circles with a pole and a length of rope to more complex systems involving chains, rollers, planks and measuring devices. And as a further note: just because you can't prove a crop circle was made by a hoaxer, you should not assume aliens were involved. Remember Occam's Razor (Section 1.6). 3.7.3: Are crop circles radioactive? -------------------------------------- This is a claim that has received wide circulation in UFO/cerealogy circles (pardon the pun). It is also untrue. Examination of the data from spectral analyses of soil taken from crop circles has shown that there were no readings above the normal background levels. The proponents of this claim are debating this, however. 3.7.4: What about cellular changes in plants within crop circles? ------------------------------------------------------------------- Yes, what about the changes? Although this is another claim that is widely circulated among ufologists and cerealogists, the evidence is simply not very good. A few photographs of alleged changes in the "crystalline structure" of wheat stems were published in some magazines and UFO publications. The method used was spagyrical analysis. This is a technique involving crystallization of the residue of organic material after harsh processing, invented three centuries ago and popularized by Sir Kenelm Digby. Digby is known for other wonderful inventions like condensation of sunlight and the development of sword salve (which you had to put on the weapon rather than on the wound, in order to cure the wound). The fact that this technique was tried at all casts serious doubts on the "researchers" involved. 3.8: Have people been abducted by UFOs? --------------------------------------- While the number of people who believe themselves to have been abducted by flying saucer aliens must number at least many thousands, not one of them has produced any physical evidence to establish the reality of their claim. On the contrary, a number of factors clearly point to a subjective basis for the "UFO abduction" phenomenon. Probably the strongest factor is that of the cultural dependence of such claims. Such claims were virtually unknown until the famous abduction story of Betty and Barney Hill received widespread publicity in the late 1960s. Also, the appearance and behavior of supposed UFO occupants varies greatly with location and year. UFO abduction claims are made much less frequently outside North America, especially in non-English-speaking countries, although foreign reports have started to catch up since the publication of Whitley Strieber's "Communion". Furthermore, the descriptions of supposed UFO aliens contain clear cultural dependencies; in North America large-headed grey aliens predominate, while in Britain abducting aliens are mostly tall, blond, and Nordic. Aliens that are claimed to steal sperm, eggs, and fetuses, or make scars or body implants on those supposedly abducted, were practically unknown before the publication of Budd Hopkins's books. This particularly alarming type of abduction seems to be quite rare outside North America. Clear "borrowings" from popular science fiction stories can be traced in certain major "UFO abductions." Barney Hill's description of his supposed abductors' "wraparound eyes" (an extreme rarity in science fiction films), first described and drawn during a hypnosis session on Feb. 22, 1964, comes just twelve days after the first broadcast of an episode of "The Outer Limits" featuring an alien of this quite unique description. Many other elements of the Hill story can be traced to the 1953 film "Invaders from Mars," including aliens having "Jimmy Durante" noses, an alien medical examination, something done to her eyes to relax her, being probed with a needle, a star map hanging on a wall, a notebook offered as a remembrance, even the imagery of a needle in the navel. Other "abductees" borrowed other ideas from "Invaders From Mars," including brain implants, aliens drilling into a human skull, and aliens seeking to revitalize a dying world. Originally, stories of UFO abductions were obtainable solely by hypnotic regression of the claimant, although in recent years the subject of "UFO abductions" has become so generally known that some subjects claim to remember their "abduction" without hypnosis. Hypnosis is a NOT a reliable method for extracting so- called "hidden memories", and its use in this manner is likely to lead to fabrication and error. Moreover, if it is suggested to a hypnotized person that fictitious events have occurred, the subject himself may come to believe this (See the article "Hypnosis" in the 1974 "Encyclopaedia Brittanica" by Martin Orne). 3.9: What is causing the strange cattle deaths? ----------------------------------------------- The only information I have on these is a long file that came to me via Len Bucuvalas <lpb@stratus.swdc.stratus.com> from ParaNet. The gist is that cattle and other animals have been found dead with strange mutilations. Organs, especially genitals, have been removed but no blood appears to have been lost. These events are also sometimes associated with reports of alien encounters and UFOs. The best source of information on cattle mutilations is the book Mute Evidence by Ian Summers and Daniel Kagan, a couple of investigative journalists who started out believing that something mysterious was happening, but ended up skeptics. SI has published James Stewart's "Cattle Mutilations: An Episode of Collective Delusion" (way back in vol. 1, no. 2, pp. 55-66). Stewart is a sociologist who examined the pattern of reports and found that new reports were inspired by previous media coverage. It came in "waves" or "flaps". 3.10: What is the face on Mars? ------------------------------- One of the Mars orbiters took a photograph of a part of Mars (Cydonia) when the sun was very low on the horizon. The picture shows a "face" and some nearby pyramids. Both these structures are seen more by their shadows than their actual shape. The pyramid shadows appear regular because their size is close to the limit of resolution of the camera, and the "face" is just a chance arrangement of shadow over a couple of hills. The human brain is very good at picking out familiar patterns in random noise, so it is not surprising that a couple of Martian surface features (out of thousands photographed) vaguely resemble a face when seen in the right light. Richard Hoagland has championed the idea that the Face is artificial, intended to resemble a human, and erected by an extraterrestrial civilization. Most other analysts concede that the resemblance is most likely accidental. Other Viking images show a smiley-faced crater and a lava flow resembling Kermit the Frog elsewhere on Mars. There exists a Mars Anomalies Research Society (sorry, don't know the address) to study the Face and related features. The Mars Observer spacecraft, scheduled for launch September 25, has a camera that can give 1.5m per pixel resolution. More details of the Cydonia formations should become available when it arrives. Anyone who wants to learn some more about this should look up "Image Processing", volume 4 issue 3, which includes enhanced images of the "face". Hoagland has written "The Monuments of Mars: A City on the Edge of Forever", North Atlantic Books, Berkeley, California, USA, 1987. [Some of this is from the sci.space FAQs] 3.11: Did Ezekiel See a Flying Saucer? -------------------------------------- The chapter in question is Ezekiel 1:4-28. This vision is an example of apocalyptic writing common in the centuries before and after Christ. (Good examples are chapters 2 and 7-12 of Daniel and the book of Revelation.) Apocalyptic literature is difficult to interpret because the language is symbolic and figurative. In some cases the writer will reveal what is meant by the symbols. Verse 28 identifies Ezekiel's wheels within wheels vision as, "the appearance of the likeness of the glory of the LORD." This "glory" is the "Khabod", a manifestation of brilliant light thought to be present in the temple. The wheels are described as appearing in a *vision* which is more like an hallucination than a physical event. The wheels are seen again in Ezekiel chap 10 leaving the temple in Jerusalem, but Ezekiel sees this while sitting inside his house which is in Babylon (see Eze. 1:1-2 and Eze. 8:1). In other words this was a message from God (or a hallucination) rather than a physical event. 3.12: What happened at Tunguska? -------------------------------- At 7:17 in the morning of June 30th 1908, close to the Stony Tunguska River, on the Central Siberian Plateau, a huge air explosion occurred. The explosion was powerful enough to be heard hundreds of miles away. The area around the Stony Tunguska River is inaccessible and consists mostly of bogs and pine forests. The seismic shocks from the explosion were detected around the Earth. The London Times of July 4th, 1908 reported "The remarkable ruddy glows which have been seen on many nights lately...seen...as far as Berlin." When an expedition eventually reached the epicentre of the explosion they found that the pine trees had been pushed over, pointing away from the centre. The trees directly under the explosion remained standing. Some small craters *were* observed at the time but have disappeared over the years due to the boggy land. The pattern is now recognised as being similar to that produced by an air-burst nuclear bomb. Currently the event is usually explained as a small, unnoticed, comet hitting the upper atmosphere somewhere over China and finally exploding a few seconds latter above Tunguska. A number of other explainations have been offered... * an atomic explosion. Some reports collected some time after the event describe a typical mushroom cloud. The problem here is that such clouds are typical of large explosions due to any cause - they are not peculiar to atomic explosions. There is also the difficulty in explaining how the Russians first developed and then forgot the technology when it would have been very useful in two major wars! * a small black hole weighing a few million tons passed through the Earth. The other entry/exit point was unnoticed as it was in the ocean. Steven Hawking has now shown that black holes of such a size have very short lives in cosmic terms due to an `evaporation' effect. * a small anti-matter meteor. This now seems very unlikely with the recent discovery of large amounts of inter-stellar matter in which, although still close to a vacuum, is quite sufficient to erode any small amount of anti-matter quite rapidly. In addition, the very existance of anti-matter in any sizable amounts in our universe is now thought to be very unlikely. * an alien spaceship, damaged and out of control, exploded during an emergency landing. There is no supporting evidence for this apart from eye witness reports of the vapour trail caused during the objects passage through the atmosphere showing a distinct `bend', which is supposed to be due to a course change. Such bends can also be found in the vapour trails of aircraft which can be seen to be flying straight and are caused by winds in the upper atmosphere. The event is not such a mystery as some suppose. In 1969 a Soviet periodical published a bibliography of more than 1000 entries. Though these are mostly in Russian it is not difficult to find references in western scientific publications. `Nature' has published a number of papers covering most of the above explanations. References John Baxter and Thomas Atkins, "The Fire Came By", Futura Publications Ltd, 1977, ISBN 0 86000 7540 0 Oliver, Charles P. "The Great Siberian Meteorite," Scientific American, Vol. 139, No. 1(1928), 42-44 Growther, J.G. "More About the Great Siberian Meteorite," Scientific American, Vol. 144, No. 5 (1931), 314-317 Zigel, Felix. "Nuclear Explosion over the Taiga: Study of the Tunguska Meteorite," Znaniye-Sila, No. 12 (1961), 24-27 [English translation available from Joint Publications Research Service, Washington, DC., JPRS-13480 (April 1962) Parry, Albert. "Russia's Rockets and Missiles" Macmillan 1962, pp 248-267 Cowan,C.,C.R. Atluri and W.F. Libby. "Possible Anti-Matter Content of the Tunguska Meteor of 1908," Nature, Vol. 206, No. 4987 (1965), 861-865 Jackson, A.A., and M.P. Ryan, "Was the Tungus Event Due to a Black Hole?", Nature, Vol. 245, No. 5420 (1973), 88-89 Faith Healing and Alternative Therapies ======================================= Disclaimer: I am not medically qualified. If you have a medical problem then I strongly recommend that you go to a qualified medical practitioner. Asking the Net for specific medical advice is always a bad idea. 4.1: Isn't western medicine reductionistic and alternatives holistic? --------------------------------------------------------------------- Practitioners of alternative therapies often put forward the idea that modern scientific medicine is reductionistic: it concentrates on those parts of the body that are not working properly, and in so doing it reduces the patient to a collection of organs. Alternative therapies try to consider the patient as a whole (a holistic approach). This is a fine piece of rhetoric, but it's wrong. It is true that modern medicine looks at the details of diseases, trying to find out exactly what is going wrong and what is causing it. But it also looks at the life of the patient, and tries to understand how the patient interacts with his/her environment and how this interaction can be improved. For instance, smoking is known to cause a wide variety of medical problems. Hence doctors advise patients to give up smoking as well as treating the individual illnesses that it causes. When a patient presents with an illness then the doctor will not only treat the illness but also try to understand how this illness was caused in order to avoid a recurrence. 4.2: What is a double-blind trial? What is a placebo? ------------------------------------------------------ A double-blind trial is the standard method for deciding whether or not a treatment has any "real" effect. A placebo is a "treatment" that has no effect except through the mind of the patient. The usual form is a pill containing a little lactose (milk-sugar), although a bitter-tasting liquid or injections of 1cc saline can be used instead. The "placebo effect" is the observed tendency for patients to display the symptoms they are told to expect. The problem is that the state of mind of a patient is often a significant factor in the effect of a course of treatment. All doctors know this; it is why "bedside manner" is considered so important. In statistical tests of new treatments it is even more important, since even a small effect from the state of mind of a small fraction of the patients in the trial can have a significant effect on the results. Hence new medicines are tested against a placebo. The patients in the trial are randomly divided into two groups. One of these groups is given the real medicine, the other is given the placebo. Neither group knows which they have been given. Hence the state of mind for both groups will be similar, and any difference between the two groups must be due to the drug. This is a blind trial. It has been found that patients can be unconsciously affected by the attitude and expectations of the doctor supplying the drug, even if the doctor does not explicitly tell them what to expect. Hence it is usual for the doctor to be equally unaware which group is which. This is a "double blind" trial. The job of remembering which group is which is given to some administrative person who does not normally come into contact with patients. This causes problems for many alternative therapies because they do something to the patient which is difficult to do in a placebo-like manner. For instance, a treatment involving the laying-on of hands cannot be done in such a way that both patient and practitioner are unaware as to whether a "real" laying on of hands has taken place. There are partial solutions to this. For instance one study employed a three-way test of drug placebo, counseling and alternative therapy. 4.3: Why should scientific criteria apply to alternative therapies? ------------------------------------------------------------------- So that we can tell if they work or not. If you take an patient and give them treatment then one of three things will happen: the patient will get better, will get worse, or will not change. And this is true whether the treatment is a course of drugs chosen by a doctor, an alternative therapy, or just counting to ten. Many alternative therapies depend on "anecdotal evidence" where particular cases got better after the therapy was applied. Almost any therapy will have some such cases, even if it actually harms the patients. And so anecdotal evidence of Mrs. X who was cured of cancer by this wonderful new treatment is not useful in deciding whether the treatment is any good. The only way to tell for sure whether or not an alternative treatment works is to use a double-blind trial, or as near to it as you can get. See the previous question. 4.4: What is homeopathy? ------------------------ Homeopathy is sometimes confused with herbalism. A herbalist prescribes herbs with known medicinal effects. Two well known examples are foxglove flowers (which contain digitalin) and willow bark (which contains aspirin). Folk remedies are now being studied extensively in order to winnow the wheat from the chaff. Homeopathists believe that if a drug produces symptoms similar to certain disease then a highly diluted form of the same drug will cure the disease. The greater the dilution, the stronger this curative effect will be (this is known as the law of Arndt-Schulz). Great importance is also attatched to the way in which the diluted solution is shaken during the dilution. People are skeptical about homeopathy because: 1: There is no known mechanism by which it can work. Many homeopathic treatments are so diluted that not one molecule of the original substance is contained in the final dose. 2: The indicator symptoms are highly subjective. Some substances have hundreds of trivial indicators. 3: Almost no clinical tests have been done. 4: It is not clear why trace impurities in the dilutants are not also fortified by the dilution mechanism. Reports of one scientific trial that seemed to provide evidence for homeopathy until a double-blind trial was set up can be found in Nature vol 333, p.816 and further, and the few issues of Nature following that, about until November of that year (1988). SI ran a good article on the origins and claims of homeopathy: Stephen Barrett, M.D., "Homeopathy: Is It Medicine?", SI, vol. 12, no. 1, Fall 1987, pp. 56-62. 4.5: What is aromatherapy? -------------------------- A belief that the essential oils of various flowers have therapeutic effects. These effects are psychological rather than physical, and so its a bit difficult to define what we mean by a statement that "it works". After all, if people do it and feel better then that is a real effect, whether it occured because of suggestion or because the flowers contain a powerful psychoactive drug. 4.6: What is reflexology? What is iridology? --------------------------------------------- Reflexology is an alternative therapy based on massage of the feet. The idea is that parts of the body can be mapped onto areas of the feet. There is no known mechanism by which massaging the feet can affect other parts of the body (other than the simple soothing and relaxing effect that any massage gives) and no evidence that it actually works. Iridology is a remarkably similar notion. Diseases are detected and diagnosed by examining the iris of the eye. A good critique of iridology: Russell S. Worrall, "Iridology: Diagnosis or Delusion?", SI, vol. 7 no. 3, pp. 23-35. 4.7: Does acupuncture work? ---------------------------- There is evidence that acupuncture treatment has an analgesic ("pain killing") effect. The mechanism seems to involve the endogenous opiate system (at least in part), but the exact mechanism by which endogenous opiates are released by acupuncture skin stimulation is not yet known. It does not appear that the effect can be explained simply by pain caused by the needles. There have been reports of measurable physiological effects, apparently via local changes in the activity of the sympathetic and parasympathetic nervous systems. While much more detail remains to be elucidated, this is at least a testable hypothesis which brings acupuncture within the realm of science. This suggests that acupuncture can be a useful tool in pain management, but that it is unlikely to be of value in curing the underlying cause of the pain. The traditional theory of acupuncture involves balancing the yin and yang (male and female principles) which flow in pathways through the body. Nothing bearing any resemblance to this has been found by medical researchers. ~References: Skrabanek, Paul: Acupuncture: Past, Present and Future. In: Examining Holistic Medicine by Stalker D & Glymour G (eds), Prometheus Books, NY Skrabanek, Paul: Acupuncture and Endorphins. Lancet 1984;i:220 Skrabanek, Paul: Acupuncture and the Age of Unreason. Lancet 1984;i:1169-1171 Skrabanek, Paul: Acupuncture-Needless Needles. Irish Medical Journal1986;79:334-335 A 1977 study, Stern, Brown, Ulett, and Sletten, 'A comparison of hypnosis, acupuncture, morphine, Valium, aspirin, and placebo in the management of experimentally induced pain,' Annals_of_the_New_York_ Academy_of_Sciences, 296, 175-193, found that acupuncture, morphine, and hypnostic analgesia all produced significantly reduced pain ratings for cold pressor and ischemic pain. Mayer,Price, Raffi, 1977, "Antagonism of acupuncture analgesia in man by the narcotic antagonist naloxone," _Brain_Research_, 121, 368-372. Sjolund, Terenius, Erikson, 1977, "Increased cerebrospinal fluid levels of endorphins after electroacupuncture," Acta_Physiologica_Scandinavica, 100, 382-384. "Practical application of acupuncture analgesia" and it's by Cheng, SB (1973 Apr 27), _Nature 242(5400)_: 559-60. "Electrophysiological measures during acupuncture-induced surgical analgesia" by Starr A (1989 Sep) _Arch Neurol 46(9)_: 1010-12. 4.8: What about psychic surgery? -------------------------------- Psychic surgeons have claimed to be able to make magical incisions, remove cancers and perform other miracles. To date, no investigation of a psychic surgeon has ever found real paranormal ability. Instead they have found one of two things: 1: Simple conjuring tricks. The "surgeons" in these cases are confidence tricksters who prey on the desperate and the foolish. 2: Delusions of grandeur. These people are even more dangerous than the first category, as their treatments may actually cause harm in addition to whatever was wrong with the patient in the first place. 4.9: What is Crystal Healing? ----------------------------- The belief that carrying a small quartz crystal will make you a healthier person. People selling these crystals use phrases like "the body's natural energy fields" and "tuning into the right vibrational frequencies". All this sounds vaguely scientific but means absolutely nothing. Crystal Healing is mostly a New Age idea. See the section on the New Age below for more information. 4.10: Does religious healing work? ---------------------------------- Miraculous healing is often put forward as a proof of the existence and approval of God. The Catholic and Christian Scientist churches in particular often claim that believers have been healed, but none of these healings have stood up to careful scrutiny. However it should be noted that the Catholic church does investigate alleged miracles. One famous "healing" which has been carefully investigated is the case of Mrs. Jean Neil. Many people have seen the video of her getting out of a wheel-chair and running around the stadium at meeting led by the German evangeist Reinhard Bonnke. This was investigated by Dr. Peter May, a GP and member of the General Synod of the Church of England. His findings were reported in the Skeptic (organ of the UK Skeptics). Here is a summary of the report. [Any errors are mine. PAJ]. May found that Mrs. Neil was helpful and enthusiastic when he contacted her, and there is little doubt that her quality of life has improved greatly since the "healing". However May was unable to find any physical changes. His report lists each of the illnesses claimed by Mrs. Neil, and he found that they were either not recorded by doctors previous to the healing or that no physical change had taken place. It seems that the only change in Mrs. Neil was in her mental state. Before the healing she was depressed and introverted. Afterwards she became happy and outgoing. A more sinister aspect of the story is the presentation of the Neil case in a video promoted by CfaN Productions. This represented Mrs. Neil before the healing as a "hopeless case", implied that she had a single serious illness rather than a series of less major ones, and included the false statement that she had been confined to a wheelchair for 25 years (in fact Mrs. Neil had used a wheelchair for about 15 months and could still walk, although with great difficulty). A report on her spine was carefully edited to include statements about her new pain-free movement but to exclude the statement that there was no evidence of physical changes. For the full report, see "The Skeptic" p9, vol. 5, no. 5, Sept. 91. Back issues are available from "The Skeptic (Dept. B), P.O. Box 475, Manchester, M60 2TH, U.K. Price UKL 2.10 for UK, UKL 2.70 elsewhere. The video is entitled "Something to Shout About --- The Documentation of a Miracle". May does not say where this can be obtained. [Does anyone know?] Of course, this does not disprove the existence of miraculous healing. Even Mrs. Neil's improvement could have been due to divine intervention rather than a sub-conscious decision to get better (as most skeptics would conclude, although the May report carefully refrains from doing so). I include this summary here because the Neil case is often cited by evangelical Christians as an undeniable miracle. In fact the case demonstrates that even such dramatic events as a cripple getting up and running may not be so very inexplicable. For more general coverage of this topic, see James Randi's book "The Faith Healers". Free Inquiry magazine has also run exposes on fraudulent faith healers like Peter Popoff and W.V. Grant. 4.11: What harm does it do anyway? ---------------------------------- People have died when alternative practitioners told them to stop taking conventional treatment. Children have died when their parents refused to give them conventional treatment. These issues matter. Most alternative treatments are harmless, so the "complementary medicine" approach where conventional and alternative therapies proceed in parallel will not hurt anyone physically (although it is a waste of time and money). Creation versus Evolution ========================= 5.1: Is the Bible evidence of anything? --------------------------------------- Apart from the beliefs of those who wrote it, no. It is true that most Christians take the truth of at least some parts of the bible as an article of faith, but non-Christians are not so constrained. Quoting the bible to such a person as "evidence" will simply cause them to question the accuracy of the bible. See the alt.atheism FAQ lists for more details. Some things in the bible are demonstrably true, but this does not make the bible evidence, since there are also things in the bible that are demonstrably false. 5.2: Could the Universe have been created old? ---------------------------------------------- An argument is sometimes put forwards along the following lines: We know from biblical evidence (see above) that the Universe is about 6,000 years old. Therefore God created it 6,000 years ago with fossils in the ground and light on its way from distant stars, so that there is no way of telling the real age of the Universe simply by looking at it. This hypothesis is unfalsifiable, and therefore not a scientific one (see the section on the scientific method). It could also be made for any date in the past (like last Tuesday). Finally it requires that God, who is alleged to speak to us through His Works, should be lying to us by setting up a misleading Creation. This seems to be rather inconsistent with Biblical claims of God being the source of all truth. Note that this argument is not put forward by creation scientists. They hold that modern science has misinterpreted the evidence about the age of the universe. 5.3: What about Carbon-14 dating? --------------------------------- Isotope dating takes advantage of the fact that radioactive materials break down at a rate independent of their environment. Any solid object that formed containing radioactive materials therefore steadily loses them to decay. If it is possible to compare the amount of radioactive material currently present with the amount originally present, one can deduce how long ago the object was formed. The amount originally present cannot, of course, be observed directly, but can be determined by indirect means, such as identifying the decay products. C-14 dating uses an unstable isotope of carbon that is constantly being produced in the upper atmosphere by cosmic rays. This process is assumed to be in equilibrium with the decay of C-14 throughout the biosphere, so the proportion of carbon that is C-14 as opposed to the stable C-12 and C-13 isotopes is essentially constant in any living organism. When an organism dies, it stops taking up new carbon from its environment, but the C-14 in its body continues to decay. By measuring the amount of C-14 left in organic remains, one can establish how long ago the organism they came from died. Because C-14 has a half-life of only a few thousand years, C-14 dating can only be used for remains less than a few tens of thousands of years old-- after that, the C-14 is entirely gone, to all practical purposes. Other isotopic dating techniques, such as potassium-argon dating, use much longer-lived radionuclides and can reliably measure dates billions of years in the past. Actually the production rate isn't all that constant, so the amount of C-14 in the biosphere varies somewhat with time. You also need to be sure that the only source of carbon for the organism was atmospheric carbon (via plants). The nominal date from a C-14 reading, based on the present concentration, therefore has to be corrected to get the real date --- but once the correction has been calculated using an independent dating tool like dendrochronology (see below), it can be applied to almost any sample. There are some known anomolies in C14 dating, such as molluscs that get their carbon from water. Creationists seem to make a habit of taking samples that are known to be useless for C14 dating, presenting them to scientists for examination, representing them as other than they are, and then claiming the anomalous dates they get for them as evidence that C14 dating is all a sham. While it is true that there *may* be unknown errors in some dating methods (see the note in section 0 about science "proving" things) this assertion cannot be used to write off isotope dating as evidence of an ancient Earth. This is because: o There are several independent ways of dating objects, including radio-isotopes, dendrochronology, position in rock strata etc. These all give a consistent picture. o Dating methods all point to an *old* Earth, about *half a million* times older than the Creationists claim. This requires dating methods which are accurate up to 6,000 years ago and then suddenly start to give completely wrong (but still consistent) answers. Even if our dating methods are out by a factor of 10 or 100, the earth is still thousands of times older than Creationists claim. 5.4: What is dendrochronology? ------------------------------ The science of dating wood by a study of annual rings. [These figures and references come from a longer summary e-mailed to me by <whheydt@pbhya.PacBell.com>. Any mistakes are mine. PAJ] Everyone knows that when you cut down a tree the cut surface shows a series of concentric rings, and that one of these rings is added each year as the tree grows. The lighter part of the ring is the summer growth and the darker part is the winter growth. Hence you can date a tree by counting the rings. But the rings are not evenly spaced. Some rings are wider than others. These correspond to good and poor growing seasons. So if you have a piece of wood cut down a few thousand years ago, you can date it by comparing the pattern of rings in your sample to known patterns in recently cut trees (Bristlecone pines exist which are over 4600 years old, and core samples allow ring counting without killing the tree). Now for the clever bit. The tree from which your sample came may have been old before any trees now alive were even saplings. So you can extend the known pattern of rings back even further, and hence date samples of wood which are even older. By lining up samples of wood in this way, dendrochronologists have been able to produce a continuous pattern of rings going back around 9,900 years. This easily refutes the chronology of Bishop Usher, who calculated from dates and ages given in the Bible that the Earth was created in 4004 BC. Dendrochronology is also valuable in providing calibration data for C14 and other isotope dating methods. See the previous question for more details. ~References: "Dendrochronology of the Bristlecone Pine....." by C. W. Ferguson, 1970. Published in a book called "Radiocarbon Variations and Absolute Chronology" This takes the record back 7484 years. I am told that more recent work published in Nature in 1991 [exact reference anyone?] has pushed this back to the 9,900 years I mentioned above. 5.5: What is evolution? Where can I find out more? --------------------------------------------------- Many creationist "refutations" of evolution are based on a straw-man argument. The technique is to misrepresent the theory of evolution, putting forward an absurd theory as "what scientists claim". The absurdity of this pseudo-evolution theory is then ridiculed. Debunking all these refutations would take a lot of space. Instead I suggest that anyone interested should go and read the FAQ lists over on talk.origins. These contain good explanations of what evolution is (and isn't). Books and essays on the subject by Stephen Jay Gould are good, and "The Blind Watchmaker" by Richard Dawkins is the sort of book that makes you want to find a creationist to argue with. 5.6: "The second law of thermodynamics says.... ----------------------------------------------- ...that entropy is always increasing. Entropy is a measure of the randomness in a system. So the universe is getting more and more disordered. But if this is so, how can life happen, since evolutionists claim essentially that life is a system that becomes more ordered with time?" In fact this is a misstatement of the law. Here is one generally accepted statement of the Second Law: No process is possible whose *sole* result is a heat flow out of a system and at a given temperature and the performance of work with that energy. In other words, you can't get work except by exploiting a temperature gradient (at least, not thermodynamically - forms of potential energy other than heat may be used - but they can also be used to make a heat gradient). Notice that this statement of the second law doesn't mention the word "disorder". In fact, the principle of entropy increase also does not, since entropy is a thermodynamic state variable whose definition is independent of such ill-defined terms as "disorder". So, where does this idea that entropy is a measure of "disorder" come from - and what does it mean anyway? Well, the idea comes from a misstatement of the theory of statistical mechanics. And the meaning is nil - since the term "disorder" has no precise scientific meaning anyway. In statistical mechanics, "entropy" is defined in terms of the number of distinct energy "microstates" that are possible within the system. This diversity of states was (and sometimes still is) informally called "disorder" by some statistical mechanics experts when trying to convey a feel for the subject to lay audiences. It was never a technical term - and never had any specific meaning in the theory. The term "disorder" applied in this way is misleading (or, at best, meaningless). A room which is messy would be informally called "disordered" by most people - even if they're ignorant (as most are) of the entropy of the room. The room might actually have a *higher* entropy after it has been cleaned. In addition the laws of thermodynamics only apply to closed systems (which the Earth is not). Small parts of such a closed system can show a decrease in entropy, but only if some other part has a higher entropy. Entropy in the system as a whole will always increase. For instance, when you freeze water the molecules of H2O line up in beautifully organised crystals. This organisation does not violate the second law of thermodynamics because the work done by the freezer in extracting the heat from the water has caused the total entropy of the *universe* to rise, even though the entropy of the *water* has decreased. Similarly the existence of life on earth has not decreased the entropy of the universe, so the second law has not been violated. 5.7: How could living organisms arise "by chance"? -------------------------------------------------- This is actually a less sophisticated version of the question above. Consider the freezing water in the example. The wonderful arrangement in crystals arises from the random movement of water molecules. But ice crystals do not require divine intervention as an explanation, and neither does the evolution of life. Also, consider a casino. An honest casino makes a profit from roulette wheels. The result of a spin of a particular wheel is purely random, but casinos make very predictable profits. So in evolutionary theory, even though the occurence of a particular mutation is random, the overall effect of improved adaptation to the environment over time is not. The actual origin of life is more problematical. If you stick some ammonia, methane and a few other simple chemicals into a jar and subject them to ultraviolet light then after a week or two you get a mixture of organic molecules, including amino acids (the building blocks of protein). So current theories propose a "primordial soup" of dilute organic chemicals. Somewhere a molecule happened to form which could make copies of itself out of other molecules floating around in the soup, and the rest is history. Ilya Prigogine's work in non-equilibrium thermodynamics (for which he received a Nobel prize) shows that thermodynamic systems far out of equilibrium tend to produce spontaneous order through what he calls "dissipative structures". Dissipative structures trade a *local* increase in orderliness for faster overall increase in entropy. Life can be viewed as a dissipative structure in exactly this sense --- not a wildly improbable freak of combinations but as a natural, indeed inevitable result of the laws of thermodynamics. 5.8: But doesn't the human body seem to be well designed? --------------------------------------------------------- Not to me. Consider a few pieces of the human body for a moment. The back for instance. The reason we poor humans suffer so much from back problems is that the back is actually not well designed. And what about human reproduction. Can you imagine any engineer being proud of having designed *that*? 5.9: What about the thousands of scientists who have become Creationists? ------------------------------------------------------------------------- This outrageous claim is frequently made by creationists, but somehow these mystery scientists are never identified. It is claimed that these conversions have been caused by "the evidence", but this evidence never seems to be forthcoming either. To test this claim, try looking up "creation" and "bible" in any biology or paleontology journal index. Even if this claim were true, it would not be a reason to become a creationist. The only reason for adopting creationism as a scientific theory would be the production of convincing evidence. 5.10: Is the Speed of Light Decreasing? --------------------------------------- The origin of this claim is a paper by Norman & Setterfield which plots various historical measurements of the speed of light and claims to show a steady decrease. Extrapolating backwards, they conclude that the Universe is only about 6,000 years old. The first point about their paper is that it was originally distributed in Stanford Research Institute covers, and is sometimes described as an SRI report. However SRI did not have anything to do with the report and are tired of answering queries about it. Norman & Setterfield appear to have selected their data in order to support their hypothesis: graphs include only those points which are close to the "theoretical" curve while ommitting points which are not close to the curve. This curve gives an inverse cosecant relationship between time and the speed of light. There is no justification for such a curve: the usual curve for a decaying value is exponential and this would have fitted the plotted data just as well as the inverse cosecant chosen by Norman and Setterfield. 5.11: What about Velikovsky? ---------------------------- In the 1950s a Russian psychologist named Immanuel Velikovsky wrote "Worlds in Collision". This book and its successors are remarkable for the density of scientific, archeological and mythological howlers. There are far to many to list here, but most are sufficient to cast serious doubt on his knowledge of any of these fields, and many are so large that even one is enough to refute the entire theory. Much of Velilovsky's proof lies in statements of the form "The reason for <X> is not known. My theory explains it as follows:". Many of these reasons were in fact known when Velikovsky wrote, and many others have been discovered since. None of these reasons bear any relationship to Velikovksy's theory. The predictive value of the theory appears to be nil. The books lack any mathematical analysis at all, which is strange considering that mathematics is the language of science, especially physics and astronomy. Some of the more noticable howlers are: 1: Strange orbits which cannot be explained in terms of Newtonian mechanics (or indeed anything less than an angel sitting on a planet and steering it like a starship!). 2: The Earth's spin being altered suddenly by a close encounter with Venus, and then restored. Where to begin? Planets just don't do that. 3: A confusion between hydrocarbons (e.g petrol, mineral oil, tar) and carbohydrates (e.g sugar, starch, glucose). 4: World-shaking events (literally) which were accurately recorded by the Isralites but not even noticed anywhere else, even quite close by. 5: Ancient records (e.g Mayan, Sumerian and Chinese astronomical observations) which contradict Velikovsky's theory. Velikovsy's supporters often cite a conspiracy theory to explain why the world of science refuses to take these ideas seriously. See section 0 of this FAQ. For more information, see: Worlds in Collision Immanuel Velikovsky Earth in Upheaval Immanuel Velikovsky Velikovsky Reconsidered The Editors of Pensee (has a lot of his papers in it, along with other papers pro-V.) Scientists Confront Velikovsky Donald Goldsmith Beyond Velikovsky: The History of a Public Controversy Henry H. Bauer Broca's Brain Carl Sagan Jim Meritt <jwm@stdb.jhuapl.edu> has posted a long article on talk.origins which systematically demolishes Velikovsky's ideas. I don't know if it is archived anywhere. This section attempts to summarise it. Most discussion of Velikovsky occurs on talk.origins. Fire-walking ============ WARNING: Whatever the truth about firewalking may be, it is a potentially dangerous activity. Do not attempt it without expert guidance. [Please could one of the firewalkers on the net contribute a paragraph or two for this section. PAJ] 6.1: Is fire-walking possible? ------------------------------ Yes. It is possible to walk on a bed of burning wood without being hurt. 6.2: Can science explain fire-walking? -------------------------------------- There are a number of theories which have been put forward to explain firewalking. Any or all may be the explanation for a particular event. o The dry wood coals used by firewalkers conduct heat very poorly. The coal itself may be very hot but it will not transfer that heat to something touching it. o The coals are a very uneven surface, and the actual surface area of foot touching the coals is very small. Hence the conduction of heat is even slower. o Wood coals have a very low heat capacity, so although they are very hot there is actually not much heat energy to be transferred to the foot. o Firewalkers do not spend very much time on the coals, and they keep moving. Jan Willem Nienhuys <wsadjw@urc.tue.nl> adds that about 1 second total contact time per foot seems on the safe side. o Blood is a good conductor of heat. What heat does get through is quickly conducted away from the soles of the feet. o The "Leidenfrost" effect may play a part. This occurs when a cold, wet object (like a foot) touches a hot, dry object (like a burning coal). The water vaporises, creating a barrier of steam between the hot and cold objects. Hence the two objects do not actually touch and evaporation from the cold object is much slower than might otherwise be expected. Since steam is a relatively poor conductor of heat the foot does not get burned. Jearl Walker, of Scientific American's "The Amateur Scientist" column, explains the Leidenfrost effect in the August 1977 issue; he walked across coals unharmed and attributes this to the Leidenfrost effect. Other scientists believe that the Leidenfrost effect is unimportant in firewalking. Some firewalkers put forward mystical explanations of why firewalking is possible. A few skeptics have challenged these firewalkers to stand on hot metal plates instead of coals. Others have pointed out that making such a challenge in the belief that the firewalker would be seriously hurt is of dubious morality. New Age ======= 7.1: What do New Agers believe? ------------------------------- An awful lot, it would seem. New Age seems to be a sort of "roll-your-own" religion. Some of the more common threads include: o Divination, especially Tarot, I-Ching, and Western and Chinese Astrology. o Green politics, especially the more extreme "deep green" movements. o Flying saucers. o "Alternative" health (see above). o Vegetarianism. o Pacifism. o Conspiracy theories to explain why the rest of the world does not follow the same beliefs. o Rejection of science and logic as tools for understanding the universe. A reliance on feelings and intuition as guides to action. o Pseudo-scientific jargon. New Agers talk about "rebalancing energy fields" and "vibrational frequencies". These sound vaguely scientific but in fact have no meaning at all. o Eastern religions, especially "cult" religions. Mainstream eastern religions such as Hinduism and Sihkism don't seem to attract New Age believers. Most New Agers are actively against organised Christianity, but some favour heretical variants such as Gnosticism. Not all of these are bad just because New Age people follow them, but the rejection of logical argument as a basis for belief and action often leads to bizarre beliefs and futile actions. A recent example was the vandalism of a GPS satellite while it was waiting to be launched. The vandals claimed that GPS was part of a nuclear first-strike system. In fact ICBMs use inertial guidance instead of GPS, and have done for decades. [Would any New Agers out there like to try summarising their beliefs in a few paragraphs for this section? PAJ] 7.2: What is the Gaia hypothesis? --------------------------------- There are several versions: Religious: The planet (or the ecosphere) is aware, or at least alive, and tries to preserve itself. Strong: The planet/ecosphere reacts to preserve a homeostasis; if, for example, global warming raises the temperature then various changes in the planet's biota will occur, which will (in some period of time) lower the temperature. Weak: Life affects the conditions of life. No scientist would disagree with the weak version given here; at the other extreme, the "religious" version is not science (unless we can find signs of that awareness). Not only can we look at the ozone hole, global warming, or human pollution, but the presence of oxygen in the atmosphere is also due to the presence of life. The strong hypothesis is very much a matter of debate. Most scientists don't believe it, some don't think it's science, but others feel they have good evidence. Some point to Le Chatelier's principle (a system in equilibrium, when disturbed, reacts to as to tend to restore the original equilibrium). However the ice ages suggest that the Earth is not in long-term equilibrium. For a range of interesting perspectives on the Gaia hypothesis, see the SF novel "Earth" by David Brin. Was Nostradamus a prophet? -------------------------- No. His supporters are very good at predicting events after the fact, often relying on doubtful translations of the original French to bolster their case. But they have had absolutely no success at predicting the future. Up until a few years ago most Nostradamus books were predicting a nuclear war in the next few years. The prophecies are very general, with lots of symbolism. It is very easy to find connections between these symbols and almost anything else, particularly if you allow multi-lingual puns and rhymes. A good general reference on Nostradamus is: The Mask of Nostradamus James Randi Charles Scribner's Sons ISBN 0-684-19056-7 BF1815.N8R35 1990 7.4: Does astrology work? ------------------------- No. A number of studies have been done which have failed to find any predictive power in astrology. Psychologists have also done studies showing that people will agree with almost any statement made about them provided that it is a mild compliment. A good report about research into astrology is: Carlson, Shawn. (1985) "A double-blind test of astrology", Nature, 318 (Dec. 5), 419-425. 7.4.1: Could astrology work by gravity? --------------------------------------- Some people argue that we are affected by the gravity of the planets (just as tides are caused by the gravity of the Moon and Sun), and that this is the connection between the motion of the planets and mundane events on Earth. Leaving aside the fact that astrology doesn't work (see above), gravity is simply too weak to do this. Gravitational force on a mass (such as a human being) decreases with the square of the distance to the other mass. But the Earth is affected just as strongly by the other mass, and accelerates slightly towards it. So the net effect on us is nil. What is important is the difference in gravity between the two sides of the mass. This decreases with the *third* power of the distance (i.e. very fast) but increases with the distance between the near and far sides. Hence the Moon and Sun cause tides because the Earth is very large. But the difference in gravity between one end of a human and the other is absolutely miniscule. Also, if this were the mechanism behind astrology then the most significant thing in astrology would be the position of the Moon, with the time of day coming second (as it is for tides). The position of the planets would be completely irrelevant because they are so much further away than the Moon and so much smaller than the Sun. 7.4.2: What is the `Mars Effect'? --------------------------------- French scientist Michael Gauquelin has discovered an apparent correlation between the position of some planets at the time of birth and the career followed as an adult. The strongest correlation is between the time when Mars rises on the day of birth and athletic prowess. However: o The Effect seems to come and go depending on exactly what the sample population is. Most of the controversy seems to revolve around who did what to which sample populations. o `Mundane' mechanisms for the Mars Effect correlations have been proposed which invoke the age grouping of school athletic activities. o Nothing found by Gaugelin bears any resemblance to classical astrology, so claims that Gaugelin has somehow "validated" astrology are bogus. 7.5: What is Kirlian Photography? --------------------------------- [Information from a posting by Dave Palmer <dpalmer@csulb.edu>] The technique involves applying a high-frequency, high-voltage electrical source (such as from a Tesla coil) to a subject. The source is also very low-current, so the subject does not get electrocuted (it's the current in electricity that does the harm, not the voltage). When this is done, an "aura" of lightning-like electrical discharges forms around the subject. This field is visible to the naked eye (in a dark room, anyway), and may be photographed. Adherents of Kirlian photography claim that this field is some sort of "life energy" which may indicate things about the subject, such as health, psychic ability, and so forth. They claim that Kirlian photography sometimes shows the "phantom effect." That is, if a limb is amputated from the subject (or, less gruesomely, if a piece is torn off a leaf), that the field will still show the missing piece for a time, because its "life energy" is still there. There is no truth to the claims that it shows any sort of "aura" or "life energy." It is merely a coronal discharge, complete with ozone production. The most damaging argument against the "life energy" claim is that Kirlian photography works on ANY subject that conducts electricity, even completely lifeless metal, or synthetic sponges soaked in salt water. The field produced jumps around quite a bit. Because the shape of the field changes, it can occasionally appear to outline non-existent areas of the subject, hence the phantom effect. Dave Palmer reports producing the phantom effect with tin foil about as often with leaves. Far more often, he got false phantom effects, that is, pictures of pieces of the subject that had never existed. Strange Machines: Free Energy and Anti-Gravity ============================================== 8.1: Why don't electrical perpetual motion machines work? --------------------------------------------------------- Electrical perpetual motion machinists usually present a machine that causes a small battery to generate a huge amount of power. The most common problem here is that the "huge amount of power" was incorrectly measured. AC power measurements are tricky; you can't just multiply the voltage and current, because they may be out of phase. Thus, measuring 10 Volts and 10 Amps could indicate anything from 0 to 100 Watts, depending on the power factor. In addition, most AC meters expect a sinusoidal wave; if they are given some other wave they may be totally wrong. A simple argument against these machines is; "If they can provide so much energy, why do they need the battery to keep going?" 8.2: Why don't mechanical perpetual motion machines work? --------------------------------------------------------- Mechanical perpetual motion machines depend on rising and descending weights. The problem is that the amount of energy that you get out of a descending weight is exactly the same amount that it took to raise the weight in the first place: gravity is said to be a "conservative" force. So no matter what the weights do, you can't get energy out. 8.3: Why don't magnetic perpetual motion machines work? ------------------------------------------------------- Magnetic motors have a clever arrangement of magnets which keeps the motor rotating forever. Not surprisingly, whenever someone tries to build one, the motor rotates for a while and then stops -- this is usually attributed to the magnets "wearing out". These motors usually rely on using magnets as low-friction bearings, meaning the "motor" can coast for a long time, but it doesn't supply any power. Magnetism is like gravity; you can store potential energy and get it back, but you can't get more energy no matter what you try. 8.4: Magnets can levitate. Where is the energy from? ----------------------------------------------------- Levitating magnets do not require energy, any more than something resting on a table requires energy. Energy is the capacity for doing work. Work can be measured by force times distance. Although the magnets are exerting a force the levitated object is stationary, so the magnets aren't supplying any energy. 8.5: But its been patented! --------------------------- So what? Patent offices will not grant a patent on a "perpetual motion machine" (some just require a working model) but if you call it a "vacuum energy device" and claim that it gets its energy from some previously unknown source then you can probably get a patent. Patent offices are there to judge whether something has been invented before, not whether it will work. The ban on devices labelled "perpetual motion" is a special case because the patent officers dislike being cited as some sort of approval by con-men. 8.6: The oil companies are conspiring to suppress my invention -------------------------------------------------------------- This is a conspiracy theory. See the entry on these in section 0. In most of the US the utility companies are *required by law* to buy your excess electricity if you produce your own. If you've got an energy machine, build it in your basement, phase match it to the line, and enjoy. 8.7: My machine gets its free energy from <X> --------------------------------------------- A number of machines have been proposed which are not "perpetual motion" machines in the sense of violating the law of conservation of energy. Mostly these are based on bogus science. One inventor claims that atoms of copper wire are being converted to energy in accordance with Einstein's "e=mc^2". However he fails to explain what causes this transformation and how this energy is converted into electrical energy rather than gamma rays or heat. Occasionally one sees a machine which could work in theory but would produce very tiny amounts of energy. For instance, one can set up a gyroscope which always points in one direction (this is how the gyrocompass in an aircraft works). The earth will rotate underneath this once every day (to an observer standing on the Earth it looks like the gyro is rotating). So you could attach gears and a generator to the gyroscope and use this rotation to get electricity. The 4,320,000:1 gearing required is left as an exercise for the student, as is naming the source of the energy it would generate. 8.8: Can gyroscopes neutralise gravity? --------------------------------------- Gyroscopes (or gyros) are a favorite of "lift" machine inventors because many people have come across them and they behave rather oddly. However there is nothing all that mysterious about the behaviour of gyros. You can use Newtonian physics to explain them. Briefly, if you imagine a bit of metal on the edge of a spinning gyro, then to turn the gyro you have to stop the bit of metal moving in its current direction and start it moving in another direction. To do this when it is moving fast you have to push it rather hard. Nothing about this makes the thing get any lighter (in fact to be pedantic, the gyro gets very slightly heavier when it spins, in accordance with Einstein's theory of relativity.) 8.9: My prototype gets lighter when I turn it on ------------------------------------------------ Weighing something which is vibrating on ordinary scales is a sure way of getting a wrong answer. The vibration from the machine combines with "stiction" in the scales to give a false reading. As a result the weight reductions reported for such machines are always close to the limits of accuracy of the scales used. AIDS ==== 9.1: What about these theories on AIDS? --------------------------------------- There are two AIDS theories that often appear in sci.skeptic. The first is Strecker's theory that the CIA invented HIV by genetic engineering; the second is Duesberg's theory that HIV has nothing to do with AIDS. 9.1.1: The Mainstream Theory ---------------------------- The generally accepted theory is that AIDS is caused by the Human Immunodeficiency Virus (HIV). There are two different versions of HIV: HIV-1 and HIV-2. These viruses are believed, on the basis of their genetic sequences, to have evolved from the Simian Immunodeficiency Virus (SIV), with HIV-2 being much more similar to SIV. Several years after the initial HIV infection, the immune system is weakened to the point where opportunistic infections occur, resulting in the syndrome of AIDS. A good reference for more information on the "mainstream" view of AIDS is: The Science of AIDS : readings from Scientific American magazine. New York : W.H. Freeman, c1989. More recently, it has been proposed that AIDS is actually an auto-immune disease (where the body's defences attack healthy cells in error) which is triggered by HIV. 9.1.2: Strecker's CIA Theory ---------------------------- Strecker's theory is that the CIA made HIV in the 1970's by combining bovine leukemia virus (BLV) and sheep visna virus (OLV). The evidence for this theory is that the government was looking at biological warfare around then, and that there are some structural similarities between HIV and BLV and visna. The evidence against this theory is: a: HIV has been found in preserved blood samples from the 1950's. [Anyone have a reference for this?] b: We didn't have the biotechnology back then for the necessary gene splicing. (But maybe the CIA has secret advanced technology?) c: The genetic sequences for HIV, SIV, BLV, and OLV are freely available (e.g. from genbank). You can look at them and compare them yourself. The HIV sequence is totally different from BLV and OLV, but is fairly similar to SIV, just as the scientists say. One school of thought holds that the "AIDS was a U.S. biological warfare experiment" myth was extensively spread as part of a dezinformatsiya campaign by Department V of the Soviet KGB (their `active measures' group). They may not have invented the premise (Soviet disinformation doctrine favored legends originated by third parties), but they added a number of signature details such as the name of the supposed development site (usually Fort Meade in Maryland) which still show up in most retellings. According to a defector who was once the KGB chief rezident in Great Britain, the KGB promulgated this legend through controlled sources in Europe and the Third World. The Third World version (only) included the claim that HIV was the result of an attempt to build a "race bomb", a plague that would kill only non-whites. Also see the question in section 0 about Conspiracy Theories. 9.1.3: Duesberg's Risk-Group Theory ----------------------------------- Duesberg's theory is: HIV is a harmless retrovirus that may serve as a marker for people in AIDS high-risk groups. AIDS is not a contagious syndrome caused by one conventional virus or microbe. AIDS is probably caused by conventional pathogenic factors: administration of blood transfusions or drugs, promiscuous male homosexual activity associated with drugs, acute parasitic infections, and malnutrition. Drugs such as AZT promote AIDS, rather than fight it. His theory is explained in detail in "Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome: Correlation but not Causation", Proc. Natl. Acad. Sci. USA V86 pp.755-764, (Feb. 1989). He claims as evidence for his theory: a: HIV does not meet Koch's postulates for the causative agent of an infectious disease. b: The conversion rate from HIV infection to AIDS depends greatly on the country and risk group membership, so HIV isn't sufficient to cause AIDS. c: The HIV virus is minimally active, does not seem to infect many cells, and is suppressed by the immune system, so how could it cause problems? d: It takes between 2 and 15 years from HIV infection for AIDS to occur. HIV should cause illness right away or never. e: HIV is similar to other retroviruses that don't cause AIDS. There seems to be nothing special about HIV that would cause AIDS. f: AIDS patients suffer very different diseases in the US and Africa, which suggests that the cofactors are responsible, not AIDS. g: How could two viruses, HIV-1 and HIV-2, evolve at the same time? It doesn't seem likely that two deadly viruses would show up together. Virtually the entire scientific community considers Duesberg a flake, although he was a respected researcher before he came out with his theory about AIDS. There is no suggestion that his theories are the result of a political agenda or homophobia. Some of the arguments against him are: a: People who receive HIV tainted blood become HIV+ and come down with AIDS. People who receive HIV-free blood don't get AIDS (unless they get HIV somewhere else). Thus, it is the HIV, not the transfusion, that causes AIDS. b: The risk factors (homosexuality, drug use, transfusions, etc.) have been around for a very long time, but AIDS doesn't show up until HIV shows up. People who engage in homosexuality, drug use, etc. but aren't exposed to HIV don't get AIDS. On the other hand, people who aren't members of "risk groups" but are exposed to HIV get AIDS. Thus, it is the HIV, not the risk factors, that causes AIDS. c: With a few recent exceptions, everyone with an AIDS-like immune deficiency tests positive for HIV. Everyone with HIV apparently gets AIDS eventually, after an average of 8 years. d: Koch's postulates are more of historical interest than practical use. There are many diseases that don't satisfy the postulates. e: It is not understood exactly how HIV causes AIDS, but a lack of understanding of the details isn't a reason to reject HIV. f: A recent study matched up people in the same risk groups and found those with HIV got AIDS but those without HIV didn't. The study was titled "HIV causes AIDS". More information can be found in published rebuttals to Duesberg, such as in Nature V345 pp.659-660 (June 21, 1990), and in Duesberg's debate with Blattner, Gallo, Temin, Science V241 pp.514-517 (1988).