What Darwin Got Wrong: summary of replies to our critics

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On our book and its reception

The first edition of our book What Darwin got wrong was first published early in 2010. It was intended to raise two objections to the Theory of Natural Selection (TNS) and to explore their connections to familiar questions about evolution.

First, we claimed that TNS is committed to an untenable externalism: Like Skinner, Darwin held that paradigm explanations of biological (and psychological) structure should invoke relations between organism and their ecologies.

Second, the tension between Darwin's treatment of selection and its treatment of selection-for. TNS holds, in effect, that though what get selected are kinds of creatures (kinds of creatures are what flourish, or fail to, in a given ecology), what creatures get selected-for are certain of their phenotypic traits (viz those phenotypic traits that cause their fitness.) Problems arise because, unlike selection, selection-for is a paradigmatically intensional concept: it is perfectly possible that there should be selection-for one, but not the other, of two coextensive phenotypic traits

In the past months we received a number of criticisms that can be replied to succinctly. We hope, at a minimum, to clear the ground for more extended discussions. We still believe in the possibility of a rational, informed, interdisciplinary, consideration of what’s wrong with the conceptual architecture of Theory of Natural Selection (TNS).

Several reviewers have suggested that we don’t know enough about biology to criticize a theory that so many biologists hold dear. Everybody makes mistakes; even biologists; even biologists who agree with one another; even great biologists like Darwin. If you think somebody has made a mistake, then it’s a good thing for you to say so, so that s/he (or you) can be corrected.

Several of the recent discoveries in biology that our book recounts lead some biologists to explicit non-Darwinian conclusions. Samir Okasha (2010) pushes them aside saying (correctly) that "they simply concern aspects of biology about which traditional neo-Darwinism didn't have much to say". But our point about these biological mechanisms is not that the neo-Darwinists don’t attend to them; but rather the marginalization of TNS that they suggest.

Replies to critiques from biologists

A frequent critique we have received is that all the non-selectionist factors and processes summarized in Part One of our book have been known to evolutionary biologists for a long time and are all perfectly compatible with TNS. This is wrong on two counts: First, because we have based that part of our book mostly on articles published in the last 5 years in specialized biology journals, and (rightly) presented as innovative by their authors; Second, because it is very hard to reconcile these discoveries with TNS, as several authors say explicitly, and almost all of them at least implicitly.

We never said that NS does not operate in the wild because it’s so hard for us to understand how it works. We say that general explanations based on natural selection are necessarily based on correlations (between the presence of a trait and greater reproductive potential), not causes. Detailed, very heterogeneous explanations of the selection for individual traits, in individual species, in their particular environments, can sometimes reveal causal factors. There is a radical difference, on which we insist in our book and in this update.

We have no doubts about the reality of evolution, or, more specifically, about the descent and radiation of species from preexisting ancestors; and we entirely accept that topological and functional transformations of internal organs offer persuasive evidence in its favor. What we seriously doubt is the power of natural selection to explain how it happens.

Replies to critiques of the conceptual situation (Part 2 of the book)

The theory of natural selection claims that a trait’s having been selected for causing reproductive success explains why a creature has it. But then it can’t also claim that “in the sense that matters” “a trait was selected for” means that it is a cause of reproductive success. For, if it did mean that, then the theory of natural selection would reduce to a trait’s being a cause of reproductive success explains its being a cause of reproductive success which explains nothing (and isn’t true).

The very heart of TNS is the thesis that, in the paradigm cases, traits are selected-for because they are causes of fitness; that is, differences of their effects on fitness explain why some traits are selected-for and others aren’t. But if that’s so, then the connection between being selected-for and being a cause of fitness can’t be definitional.

Nobody doubts, of course, that evolution is law-governed; after all, the laws of physics apply to everything. The present issue is whether there are biological laws of evolution; that is, laws of evolution that are defined over biological kinds (such as, for example, laws about evolution defined over ecological properties so described and their effects on fitness so described.) Missing this point has lead to all sorts of confusion including, notably, the suggestion that if there are no laws of evolution, determinism and/or mechanism are ipso facto undermined

Given all that, could there be such laws about how creature/environment interactions determine fitness? In principle, sure there could. But are there such laws? We think the probability is asymptotically close to nil. The kind of complexity that does tell against a putative law is the kind that proliferates kinds beyond necessity.

A species of jellyfish (the cubozoan jellyfish, Tridpedalia cystophora discovered in the waters near Puerto Rico) has 24 globular eyes in 6 groups of 4 (called rhopalia), very similar to our vertebrate eyes, but no brain to collect the images, no optic nerve, and the lenses can only form images behind the retina. No adaptive explanation is in sight, though the genetic and developmental mechanisms responsible for this feast of structure without function are well understood.

Conclusion

We continue to believe that there’s a lot that Darwin Got Wrong. We continue to believe that the issues implied by the externalism of his account of selection, and by his failure to notice the intensionality of selection-for, are in need of thorough and careful consideration. Thus far, the critical responses to our attempts have not been edifying; mostly a howl of reflexive Darwinism, with very little attention paid either to the structure of the arguments or to their repercussions. But we’re told that hope springs eternal. Our hope, at a minimum, is to have cleared the ground for calmer and much more responsible polemics. We still believe in the possibility of a rational, interdisciplinary, discussion of the empirical warrant and the conceptual architecture of TNS. But we must admit that we don’t believe in it now as much as we did a year ago.

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