What Darwin Got Wrong
| The divine comedy|
What Darwin Got Wrong is a book by philosopher/cognitive scientist Jerry Fodor and cognitive scientist Massimo Piattelli-Palmarini. While claiming to accept the reality of evolution, the authors attack as incoherent the idea of natural selection (NS).
The problem of selection-for
The core argument (see chapter 6) is quite peculiar, and surrounds what the authors call "the problem of selection-for". In short, a trait such as a heart is putatively a product of natural selection, evolved for pumping blood, but such traits usually come along with other features, such as making a heart-like noise. The theory of natural selection says that it is the fitness enhancing trait (pumping blood) that is "selected for." With this in mind, the authors claim that the theory of natural selection cannot do what it purports to do (that is, be an explanatory theory of trait fixation) without an account of "selects for." But because "selection for" is an intensional concept, it requires an intensional causal explanation. The only available intensional explanations either (i) appeal to minds, or (ii) appeal to nomological laws. (i) is ruled out because there is no gardener in nature, and (ii) is ruled out because there are no nomological laws at the biological level. So, the authors conclude, natural selection cannot do what it purports to do.
However in critique of this, the philosopher of biology Michael Ruse has pointed out that Fodor and Piattelli-Palmarini are completely wrong to introduce intentionality: although talk of an intention behind a design is often used as a metaphor in evolutionary biology, it is no more than a metaphor and design plays no role in the theory of evolution. Questions of what traits increase survival and what are happenstance can be solved by experiment without recourse to ideas of intentionality: "we can ferret out which features are most useful and which are just along for the ride. Suppose eyes, which are surely necessary, are linked to tufts of hair, which may not be. Well, experiment and see how the organisms get along without eyes and then without hair."
Comparisons to Skinner
Creationists have however heaped praise upon the comparison made by the book between natural selection and B.F. Skinner's theory of learning. The authors claim the two are nearly identical. Skinner's theory of learning is, we are told, now widely rejected. Yet this is irrelevant: if the theory fails it is because it is a bad theory of mind; natural selection however is not intended as a theory of mind, and must be judged instead as a theory about evolution.
At times the authors seem to endorse the irreducible complexity argument. For example, they discuss (chapter 5) the complex behaviour of a particular wasp, Ampulex compressa, which involves paralysing a cockroach with behaviour-altering toxins that enable the wasp to actually lead it to its nest. The authors consider this all too complex to have evolved by natural selection:
- "[It can't be true] that all kinds of alternatives have been blindly tried out by the ancestors of the wasp "
This misrepresents how evolution by natural selection is supposed to work. Evolution does not try out every possible trait an organism could conceivably have, but makes minor modifications to traits that already exist. Complex traits are the result of gradual modifications of simpler traits, over millions of years.
Curiously, the authors accept artificial selection, because one can appeal to the mind of the selector to determine what is being selected for. Yet it's unclear how the presence or absence of a mind makes any difference to the outcome of selection; all that matters is that different individuals have different reproductive success, resulting in a change of gene frequencies over time.
- Book review by Michael Ruse
- Book review by Ned Block and Philip Kitcher
- Book review by Bob O'Hara
- Book review by Massimo Pigliucci
- Book review by Peter Forbes