Why Pigs Don’t Have Wings

My comments to the everything-list while discussing Fodor’s paper Why Pigs Don’t Have Wings

https://groups.google.com/forum/#!topic/everything-list/xcBi6v8SAg4

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To understand Fodor’s answer it is necessary to understand his argument. Shortly:

1) Natural selection is assumed to be unintentional. It just happens but it does not has a goal.

2) The existence of coextensive traits in the organism is the rule. Hence natural selection should not only select a trait, rather it must select for.

3) “Select for” is a part of an intentional process. Hence according to the point 1, natural selection cannot select for.

Whiteness of a polar bear is an coextensive trait. To select it means to select it for. Natural selection cannot do it.

Well, one has also to define natural selection more carefully, as it happens that different people understand what natural selection is differently. Fodor’s definition to this end is in the paper.

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That’s what most comments to Fodor’s argument look like: this is false because it must be false. But this king of answers are not that impressive. It is up to you to believe that Fodor is wrong but if you what to prove it, you must invest more time.

This is for example how Fodor describes natural selection:

“One is its familiar historical account of our phylogeny; the other is the theory of natural selection, which purports to characterise the mechanism not just of the formation of species, but of all evolutionary changes in the innate properties of organisms. According to selection theory, a creature’s ‘phenotype’ – the inventory of its heritable traits, including, notably, its heritable mental traits – is an adaptation to the demands of its ecological situation. Adaptation is a name for the process by which environmental variables select among the creatures in a population the ones whose heritable properties are most fit for survival and reproduction. So environmental selection for fitness is (perhaps plus or minus a bit) the process par excellence that prunes the evolutionary tree.”

There is more to this end in his paper. Finally, this is what Darwin writes about natural selection in On the Origin of Species:

“[natural selection] is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good….”

This is exactly what Fodor rejects.

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I would agree with you that my Darwin’s quote does not express all the Darwin theory. The point was rather that among what Darwin has wrote one can find such statements as well.

I should say that I took this quote from Lewontin’s review on the book Jerry Fodor and Massimo Piattelli-Palmarini “What Darwin Got Wrong”

http://www.nybooks.com/articles/archives/2010/may/27/not-so-natural-selection/

In the book you will find more references on how biologists define natural selection. In Lewontin’s review by the way you will find similar critique of adaptationism.

I personally like a document

Units and Levels of Selection
http://plato.stanford.edu/entries/selection-units/

where you will find a modern review of what biologists say. Let me quote from Section 2.4 The Manifestor of Adaptation Question about “engineering” adaptation.

“Some, if not most, of this confusion is a result of a very important but neglected duality in the meaning of “adaptation” (in spite of useful discussions in Brandon 1978, Burian 1983, Krimbas 1984, Sober 1984). Sometimes “adaptation” is taken to signify any trait at all that is a direct result of a selection process at that level. In this view, any trait that arises directly from a selection process is claimed to be, by definition, an adaptation (e.g. Sober 1984; Brandon 1985, 1990; Arnold and Fristrup 1982). Sometimes, on the other hand, the term “adaptation” is reserved for traits that are “good for” their owners, that is, those that provide a “better fit” with the environment, and that intuitively satisfy some notion of “good engineering.”[7] These two meanings of adaptation, the selection-product and engineering definitions respectively, are distinct, and in some cases, incompatible.”

Note that “engineering” adaptation is exactly “selection for”. Hence Fodor has not made it up. This is what you find reading at least some famous biologists.

In general, the starting point for Fodor were explanations as follows

‘We like telling stories because telling stories exercises the imagination and an imagination would have been a good thing for a hunter-gatherer to have.’

It is a typical explanation based on natural selection that you meet quite often nowadays. It is also similar to what was written in the paper on mathematics and physics. Yet, to prove it one must assume that natural selection can “select for”. Otherwise it will not work. The reason is related to coextensive traits. Provided one would like to prove the statement above by natural selection, one must explain selection of a particular coextensive trait. Yet, natural selection cannot differentiate coextensive traits, as they occur in nature simultaneously.

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