“All swans are underlyingly white”

An allegory that I started writing for something else, but which upon reflection should probably stand on its own.

Once upon a time, in a world closely alike our own, a biologist postulates a generalization: “All swans are white”. The hypothesis performs admirably for a time and appears to predict quite strongly the coloration of swans.

Small updates to the emerging theory are gradually accepted: for example, the impact of diseases, oil spills or Diogenean paint-set-wielding jokers on the coloration of swans is admitted via an adjustment “All swans are naturally white”. Likewise, objections drawn from the study of the beaks, flesh, skin, etc. of swans are admitted via a further adjustment “All swans’ mature plumage is naturally white”. Regardless, the original formulation remains in circulation, even if by now generally understood to be shorthand for the more nuanced version; and all remains well in the field of Generalizative Biology.

One day, however, a serious disaster appears to strike, as reports of black swans arrive from the far-away land of Australia. Some initial ways of explaining away this pesky conflicting evidence are explored: perhaps the birds in question have a peculiar habit of taking dust baths in coal beds; perhaps the birds possess not true plumage but a neotenous extension of the downy (and non-white) body covering of young swans; or perhaps their blackness indeed disqualifies them from being considered “swans”. However, detailed study of their behavior, genetics, etc. eventually proves these approaches untenable. The birds in question are in all appearences just another species of swan — except for its atypical plumage. Generalizative Biologists remain irked by this blemish upon their valued theoretical stance that all swans are white; thus far one of their most strongly established results in the field of animal coloration. It is proposed by some naïve outsiders that the theory has simply been falsified, but such busybodies universally fail to propose any new, better theory in its stead. How else would one explain the repeated and well-replicated observation that swans everywhere else appear white? A weakening to a mere “some swans are white” would have no predictive power, and it would clearly be a great failure of parsimony to posit that dozens of swan species are individually white, but with nothing common between these individual facts.

In the minor field of historical biology, it is pointed out that black and white swans alike likely descend from a white ancestor. This does not generate much disagreement as such (by definition the proto-swan has been a swan, and hence is clearly predicted to have been white), but at the same time is agreed to not be an answer to the problem of black swans. Swans must be describable as synchronic biological systems! Their identity as swans cannot hinge on evolutionary theory. After all, has not the concept of swans — even including the problem of black swans — been already defined long before anyone had heard of evolutionary biology?

Finally a new promising theory is found. Informed by close study of the developmental history of swans, it appears that black swans’ plumage only gains its coloration by a pigment. It is shown in careful experiments that, without this pigment, the plumage would rather turn out white! This immediately gives a new, seemingly paradoxal result. Even black swans are white after all — that is to say, white in (what comes to be called) their underlying anatomy, and only seemingly black due to (what comes to be called) their individual bodily realization. All biology, of course, has for long recognized that members of a species often differ in their individual bodies: taller, shorter, missing digits or having additional ones, indeed sometimes albino; and that this should not be seen as invalidating their identity as members of a species with a certain typical height, number of digits, or coloration. But the recognition that such individual processes can be highly widespread across a species proves revolutionary.

The theory of underlying anatomy quickly finds applications to several seemingly unrelated problems. The hooded crow, for example, turns out to be not a true counterexample of the old but contentious theory that “all crows are black”: it can be treated as a completely typical, underlyingly black crow (instead of e.g. the popular earlier theory to identify it as being actually a remarkably large and crow-like magpie). Likewise, the old suggestion that “all birds have wings” proves to be underlyingly true and only superficially contradicted by species such as the kiwi or, by some views, the ostrich. Even the older hedge about swans being only naturally white proves to be but a trivial special case of the new theory: e.g. any swan spraypainted green remains, of course, still underlyingly white. All this is widely seen as strong evidence for the validity of the concept; and thus, the problem of black swans has, in the end, only made Generalizative Biology stronger.

Some still occasionally express confusion about the nature of underlying anatomy, mostly people without proper training in theoretical anatomy (lamentably including even several experimental anatomists). It is admitted, of course, that experimental correlates of underlying anatomy remain difficult to identify. However, even if one for some reason sees fit to completely ignore e.g. the original pigmentation studies among the black swans, what of other case studies such as the embryological evidence for humans as an underlyingly tailed species? the fossil and written evidence for lions as an underlyingly European species? or any other number of such demonstrations? No, all accumulated evidence must surely be taken in favor of underlying anatomy as the main cause behind organisms’ observable biology. And the theory clearly advances by the day — why, just last year it was argued that even horses, too, share the important mammalian universal of five underlying digits.

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Posted in Methodology
6 comments on ““All swans are underlyingly white”
  1. David Marjanović says:

    I love it.

    Kiwis, BTW, do have tiny forelimbs (with one clawed finger, funnily enough) underlying their flank plumage. Complete absence of forelimbs – a shoulder girdle without a shoulder joint – occurs in moas.

  2. Ante Aikio says:

    Regarding this topic, I suppose you are acquainted with Esa Itkonen’s classical paper “Concerning the generative paradigm” (published in Journal of Pragmatics, 1996):

    Click to access Chomsky.pdf

  3. Y says:

    There is no question that WhtPlume is a universal constraint. It’s just that BlkPlume is sometimes ordered higher.

  4. B. Blasebalg says:

    Very nice.
    Is it fair to call that a “science fable”?

  5. […] Freelance reconstruction is a blog by J. Pystynen about historical linguistics, engaging occasionally with generative grammar, see e.g. the blog posts Analogy Is Not Phonology or “All swans are underlyingly white”. […]

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