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- Neutral Models in Biology
- (Eds) Matthew H. Nitecki and Antoni Hoffman
- Oxford University Press 1987
- pp. 166
- [ biology, philosophy of science ]
-
- _Neutral Models in Biology_ is a collection of eight essays on the use
- of "neutral" (or null) models in biology. While the title sounds rather
- narrow, the essays in fact raise and discuss broader issues within the
- philosophy of science. Here I discuss the essays in the order they come
- in the book, grouped in in sections titled "Molecular and Genetic
- Models", "Ecological Models" and "Palaeontological Models".
-
- In "Neutral Models in Molecular Evolution" James Crow gives an overview
- of the well known neutral theory of molecular evolution (which is
- probably the first theory that springs to mind when one mentions the
- word "neutral" in a biological context.) He doesn't make any explicit
- reference to work in the philosophy of science, but he discusses in
- separate sections the theory's predictive value, heuristic value,
- explanatory value and usefulness. Wimsatt's "False Models as Means to
- Truer Theories" is a broader look at the role of false models in science
- generally, illustrated by the development of the linear chromosome
- theory by the Morgan school around the 1920s. Most of what he says is
- applicable to broader science quite generally. In "Self-Organisation,
- Selective Adaptation, and Its Limits: A New Pattern of Influence in
- Evolution and Development" Kauffman models the genomic regulatory
- system as a network of Boolean switches. He presents the results of
- simulation studies which suggest that (under some fairly reasonable
- assumptions) there are generic statistical properties of such systems
- that may be largely "immune" to selective effects and so can be
- considered ahistorical universals.
-
- "How to be Objective in Community Studies" looks at the methodological
- (and metaphysical) difficulties involved in defining "ecological
- community". This is formulated within a more general philosophical
- background (with references to Goedel and Popper among others). The
- essay "On the Use of Null Hypotheses in Biogeography" by Paul Harvey is
- probably the most narrow (specific :-) of the essays, being a discussion
- of the use of Species x Island tables in searching for evidence of
- competitive exclusion.
-
- "Neutral Models in Paleobiology" uses neutral models to test
- explanations (or rather the need for explanations) for four different
- palaeobiological facts: the extinction of the trilobites, the periodicity
- of extinction events during the last 250 million years, the diversity of
- Ordovician faunas and evolutionary filling of morphospace in the coiling
- of Ammonoidea. In the first two cases the neutral model is rejected,
- giving some plausibility to alternative causal explanations, while in
- the third the sufficiency of the neutral model can be used to deny the
- need for an explanation. In the final case the construction of a neutral
- model appropriate for testing the hypothesis in question is not
- possible, but this in itself tells us something about the limitations
- of our knowledge.
-
- "Neutral Model of Taxonomic Diversification in the Phanerozoic: A
- Methodological Discussion" argues that the data are not detailed enough
- to decide between the neutral model and alternative periodic theories.
- "Testing Hypotheses or Fitting Models? Another Look at Mass Extinctions"
- is an essay by a statistician who has his own views on the use of models
- in biology. He sees himself as a "factory representative" selling
- statistical tools to customers, and his essay shows off some modern
- statistical methods in an analysis of the importance of mass extinctions
- relative to background extinctions. Along with all of this comes some
- general advice (and some warnings) about the use of statistical methods
- (including a warning about the unwarranted connotations of "neutral").
-
- Even the most specialised of the essays is presented in such a way as to
- be understandable without any extremely technical knowledge. (All the
- essays do assume fundamental biological knowledge and basic statistical
- competence.) As a result the philosophical and methodological insights
- they have to offer are accessible to all biologists, and the essays that
- are broader in scope will also be of interest to scientists in other
- fields. The most impressive thing about the volume is the authors'
- philosophical and statistical/mathematical sophistication. They consider
- and use ideas produced by philosophers of science (Popper, Kuhn,
- Lakatos, Feyerabend, Duhem, Quine, etc. all get mentions) without
- subscribing themselves to any narrow conception of scientifoc method.
- Similarly they are happy to use statistical tools, but are always
- careful to consider their appropriateness and significance first.
-
- Danny Yee (danny@cs.su.oz.au)
- 28/7/93
-
-