A 'successful' RNA molecule in a test-tube is successful because of some direct, intrinsic property of itself, something analogous to the 'stickiness' of my hypothetical example. But properties like 'stickiness' are rather boring. They are elementary properties of the replicator itself, properties that have a direct effect on its probability of being replicated. What if the replicator has some effect upon something else, which affects something else, which affects something else, which . . . eventually, indirectly affects the replicator's chance of being replicated? You can see that, if long chains of causes like this existed, the fundamental truism would still hold. Replicators that happen to have what it takes to get replicated would come to predominate in the world, no matter how long and indirect the chain of causal links by which they influence their probability of being replicated. And, by the same token, the world will come to be filled with the links in this causal chain. We shall see those links, and marvel at them.
