Vol. 29 No. 21 · 1 November 2007

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Why Pigs Don’t Have Wings

My colleague Jerry Fodor has added his name to the list of those who have taken themselves to have ‘conceptual’ objections to the idea of adaptation by natural selection (LRB, 18 October). His problem is fortunately quite easily solved. He takes from Stephen Jay Gould and Richard Lewontin the question: if two traits occur together, how do we know which was ‘selected’ for without appeal to the mind of a designer? Fodor urges that when we take away the designer, the question is unanswerable, unless we make a metaphorical and flat-footed appeal to Mother Nature. But this is not so. Two traits may be found together in nature, but one can play a causal role in producing a reproductive advantage, when the other does not. It may be that all and only vertebrates with eyes weigh a little bit extra because they carry various proteins (crystallins) around that go to making up eyeballs. But the sensitivity to light is what gives the advantage, not the little bit of extra weight due to carrying crystallin. Otherwise flatfish might as well have eyes on their undersides, and we might have turned out blind, but with devices for holding crystallin in our armpits. Similarly Fodor triumphantly asks whether it is being white or being the same colour as the environment that is good for polar bears. A brief look at the life of polar bears, and other bears, and animals such as ptarmigan or mountain hares that change colour with the seasons, forces just one answer. Camouflage helps across the board; being white only helps when it coincides with it.

Simon Blackburn
Department of Philosophy, University of Cambridge

When one is consciously designing something, it makes perfect sense to say that some features are there on purpose, others mere side-effects of intentional decisions. Jerry Fodor thinks that no parallel distinction is available in the mindless world of evolution, hence there is no way to say which organic traits are adaptations, and which are merely side-effects of selection going on somewhere else. This, he believes, means that the very ideas of adaptation and natural selection are incoherent.

Yet Fodor’s comments later in his article suggest a perfectly good answer to a problem he says is insoluble. He tells us that ‘curly tails aren’t fitness-enhancing, they just happen to be linked to tameness, so selection for the second willy-nilly selects the first.’ To be sure, he is discussing an example of an artificially selected trait. Even so, the conceptual resource he uses to distinguish between the trait that is selected for, and the trait that is merely linked to one that is selected for, is fitness enhancement, and there is nothing in this concept that draws on notions of what a designer intentionally chooses. If Fodor’s test for adaptation works in the realm of artificial selection, it works in the realm of natural selection, too.

Further, Fodor suggests that most attempts to make adaptation respectable appeal to suspect metaphors of what Mother Nature is aiming at. Some do, but here is the philosopher of biology Elliott Sober’s solution to the problem, which he gave in 1984, and which is basically the same as Fodor’s own implicit proposal: ‘“Selection of" pertains to the effects of a selection process, whereas “selection for" describes its causes. To say there is selection for a given property means that having the property causes success in survival and reproduction.’ If a property doesn’t cause success in survival and reproduction, but is linked to one that does, then there is no selection for that property. This is precisely why Fodor thinks that although there is selection of curly tails, there is no selection for curly tails.

Finally, Fodor tells us that ‘the crucial test is whether one’s pet theory can distinguish between selection for trait A and selection for trait B when A and B are coextensive: were polar bears selected for being white or for matching their environment? Search me; and search any kind of adaptationism I’ve heard of.’ What adaptationists need is a test that tells them, for example, whether there is selection for polar bears having white fur, having warm fur, or both. The Fodor/Sober test can tell us that: if we dye the fur of polar bears green and there is no impact on their survival or reproduction, then this provides evidence that there is selection for warm fur, and that whiteness simply follows along because whiteness and warmth are linked. But it is not necessary that our test tell us whether there is selection for whiteness or for matching the environment. If you dyed the fur of polar bears green, then they would also fail to match their environment. If we then observe that they do worse in terms of survival and reproduction, our test suggests that there is selection both for being white, and for matching the environment. But that is hardly surprising, because polar bears are camouflaged in virtue of being white. The fact that our test doesn’t discriminate between selection favouring whiteness and selection favouring matching the background doesn’t show that we have a test with no discriminatory power. It consequently fails to undermine the distinction between ‘selection of’ and ‘selection for’, it fails to show that the concept of adaptation is flawed, and it fails to make problems for natural selection.

Tim Lewens
History and Philosophy of Science, University of Cambridge

There is a significant word missing from Jerry Fodor’s entertaining dismissal of Darwinian theory: variation. Darwin starts The Origin of Species by ruminating on the causes of variation within species, particularly species that have been domesticated. Variation allows for differential chances of survival of members of a species through processes of natural selection; some, by virtue of being somewhat different from their conspecifics, will be better able to cope with environmental pressures and be more likely to survive, procreate and hence pass on their genes to the next generation. This is why, in Darwin’s original formulation, evolution occurs through processes of natural variation and natural selection. What Fodor appears to be attacking is not so much natural selection but rather an extreme adaptationist view of the evolutionary process wherein each and every trait of an animal is held to arise as an adaptation to the environment. But it would be difficult to find any reasoned expression of such a view; as Fodor himself points out, pigs don’t have wings not because it would not be evolutionarily advantageous for them to fly, but because they’re just not built that way.

Ian Cross
Faculty of Music, University of Cambridge


I was surprised to see Anne Enright quoting Macbeth, Act III, Scene ii, as ‘We have scorched the snake, not killed it’ (LRB, 4 October). The line I learned at school, in Scotland long ago, was ‘We have scotched the snake, not killed it,’ and this version appears in all the editions I can find to hand. The Chambers Dictionary informs me that the ‘scotched’ reading originates in a ‘conjecture’ in the 1734 edition by Lewis Theobald, who decided that ‘scorched’ in earlier editions had been a misreading of a manuscript. But it strikes me as an astute conjecture, and it is supported by the line in Coriolanus, Act IV, Scene v, that describes a combatant as ‘scotch’d and notch’d like a carbonado’. This meaning of ‘scotch’ seems to come from the Norman French éscocher, ‘to cut notches’ (as snake-meat, for example, would be slashed cross-wise, for broiling on coals); whereas ‘scorch’ probably derives from écorcher, ‘to strip or flay’. I feel sure that the ‘snake’ was meant to be slashed or gashed, not skinned alive or burned.

Gerald Mangan
Pavillons-sous-Bois, France

After Strachey

While it is true, as Adam Phillips says of Freud, that the translations in the Standard Edition are essentially the work of one man, James Strachey, it should be remembered that extensive work was done by the late Angela Richards on the Pelican Freud Library, and it was those translations that reached the general reader (LRB, 4 October). After Richards graduated from Oxford in the early 1950s with a degree in modern languages, it became her full-time job to retranslate Strachey by checking his text against Freud’s. Several of the Pelican volumes, such as The Interpretation of Dreams (1976), acknowledge her contribution on the title page with the line: ‘The present edition revised by Angela Richards’. She was the youngest daughter of Noel Richards (née Olivier), one of Rupert Brooke’s loves, and it has been suggested that James Strachey, who had an affair with Noel, was her father. At any rate his indebtedness to her work on the translations is acknowledged in the fact that he left her his share of the Freud royalties.

Anthony Curtis
London W8


Rash of me to fancy a French defeat at the hands of New Zealand in the rugby world cup (LRB, 18 October). The statistics looked good, and they will again. After their victory at Cardiff on 6 October, the French now have 11 wins and one draw against the All Blacks from a total of 46 encounters. The jittery teams of the northern hemisphere are still long-haul contenders in international rugby – two of them anyhow. It’s something the great, confident sides of the south – two of them anyhow – find hard to bear. After their elimination in the quarter-final, brilliant Australian players suddenly became Weeping Matildas, fluttering home to the Murdoch billabong, while a superb member of the All Black squad opted in defeat for a King Kong routine, stomping on cars at Heathrow. Crying and stomping, it seems, are now integral to the story.

Jeremy Harding
Saint Michel de Rivière, France

A pedant writes

I expect there is a valid debate to be had on ‘masterly’ v. ‘masterful’, but my greater concern is with Martin Sanderson’s attack on ‘referenda’ (Letters, 4 October). ‘Referendum’ as used by Perry Anderson is an English language word, albeit adopted from Latin. Its plural form is derived as a matter of usage; ‘referenda’ and ‘referendums’ are both in common usage and in that sense are both correct. The Oxford Dictionary for Writers and Editors (1981) recommends ‘referendums’, and this form, according to the Oxford English Dictionary, seems likely to prevail. We shall see. Official attempts to regulate language, however logically, generally fail.

Although ‘watering the gerania’ was an amusing end to Mr Sanderson’s letter, it is unfortunately an example of arguing by (in this case, false) analogy, ‘geranium’ not being a gerund. A much better analogy is that ‘no one in their right minds’ would talk about ‘agendums’ (‘agendum’ being a gerund and therefore exactly analogous to ‘referendum’).

Ken Sunshine
Bishopsteignton, Devon

Stockhausen, not Henze

Julian Barnes mistakenly attributes to Hans Werner Henze the remark that the attacks on the World Trade Center were ‘the greatest artwork ever made’ (LRB, 4 October). In fact, it was Karlheinz Stockhausen who said to reporters in Hamburg a few days later that the destruction of the towers was ‘the greatest work of art that is possible in the whole cosmos’. In response to the furore in the press, Stockhausen issued a clarification, noting that he ‘used the designation “work of art" to mean the work of destruction personified in Lucifer’.

Grey Anderson
Yale University

Great-Uncle Julius

T.P. Wiseman refers to Augustus and ‘his father, Julius Caesar’ (LRB, 18 October). Adoptive father, yes, but Julius was Augustus’ great uncle, formally adopting him only in his will in 44 BC. The patrilineage was fabricated for political purposes, like many of the other genealogies discussed by Wiseman.

Stan Smith

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