Sunday, May 26, 2013

The Ontology of Biology (mise à jour)

We treated of this in some detail in our core essasy, “On What There Is”.  Indeed, the details of this particular discipline threatened to overwhelm that general survey.  Accordingly, we remove to this adjacent seminar-room, for a few additional remarks.

Let it be said, that biology, dealing with actual palpable furry waddling entities, would not appear a priori  a likely arena of serious ontological doubts.   Physics, by contrast, can’t avoid such scruples, since it deals largely with the unseen, and postulates just about everything.  Mathematics, freilich:  it being (as some would see it) about Being itself.   The only reason, then, that the study of biology figures so prominently in our remarks, is the extraordinarily high level of methodological and even philosophical thinking that has been invested in the evolutionary enterprise, beginning with Darwin himself. 

We shall begin, as we love to do, with a quote from Quine:

When we say that some zoölogical species are cross-fertile, we are committing ourselves to recognizing   as entities  the several species themselves, abstract though they are.
-- Quine, “On What There Is”.

This is true -- indeed, true virtually as a matter of sheer quantificational logic; but its proper biological content is nil -- as Quine well knows.   We may avoid this purely formal commitment by “so paraphrasing the statement  as to show that the seeming reference to species on the part of our bound variable  was an avoidable manner of speaking.”  (The substantive, as the saying goes, can be pegasized away.)

~     ~     ~

In our essay above-referenced, we focussed on the ontological tug-of-war between species and gene as the favored stockkeeping unit of evolution.  But whatever the upshot of that, species themselves are obviously central.  Only … what are they?

As so often, Darwin was ahead of the time he himself largely created.  Coyne & Orr quote his Origin of Species (1859):  “We shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations  made for convenience.”

And to similar effect:
J.B.S. Haldane observed that “the concept of a species  is a concession to our linguistic habits  and neurological mechanisms”…
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 11

And again:
Ridley notes:  “The fact that independently observing humans  see much the same species in nature  does not show that species are real rather than nominal categories.  The most it shows  is that all human brains are wired up with a similar perceptual cluster statistic.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 14

Why are organisms apportioned into clusters separated by gaps? … Dobzhansky (1935) found this question intractable:  “The manifest tendency of life toward formation of discrete arrays  is not deducible from any a priori considerations.  It is simply a fact to be reckoned with.”  … While history can create discrete clusters containing groups of species, we do not see how it can produce species themselves.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 49

Biologists… even questioned whether species exist.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 5

…whether species are real entities  or arbitrary constructs of the human mind.  [This is the Nominalist or ‘hocus-pocus’ position. -- dbj]  Several lines of evidence  show that species are real.   …  One asks whether assemblages of individuals -- populations -- are partitioned into discrete units that are objective, not subjective.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 7, 10

(To see how far- or over-reaching such scepticism is, for species substitute coffee-cups.)

We pause to marvel at such self-critical ontological nominalism about the central practical entities of one’s own discipline.  As though:
Dentists:  When we speak of ‘teeth’, this is a largely arbitrary demarcation among the hard structures of the body.
Football coaches:  To counterpose ‘offense’ and ‘defense’ is to indulge a false dichotomy -- which is, however, useful for certain purposes.
Patrolmen’s Benevolent Association:  To talk of ‘crime’ is, of course, merely a façon de parler.

Systematists, whose task is unraveling the history of life, often prefer species concepts  different from those used by evolutionists more interested in evolutionary processes.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 10

~  Posthumous Endorsement ~
"If I were alive today, and in the mood for a mystery,
this is what I'd be reading: "
(I am Carl Linnaeus, and I approved this message.)
~         ~

Another ontological posit:

Cluster analysis distinguished 32 fairly discrete groups in phenotypic space (“phenons”).
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 23

(One’s heart rather sinks, reading this.  Recall the profusion of dubious -emes in linguistics.)

… the essential dialectical unity of the biological and the social,  not as two distinct spheres … but as ontologically coterminous.
Lewontin, Rose, & Kamin, Not in Our Genes (1984)

All species concepts require some subjective judgments.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 34

This, from a pair of very hard-headed writers.  Cf. similar points by Keynes in his Treatise on Probability (1921).

Because we rejected ecological differentiation as part of the Biological Species Concept in sexually reproducing groups, we obviously endorse the use of different species concepts in different groups.  We do not consider this pluralism to be a weakness of the BSC.  Because the causes of discreteness may well differ among taxa, so may the concepts appropriate to addressing the species problem.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 52

Since this astute observation strikes me as very sound, I shall give it a nice name:  not Nominalism about species, but Polytypic Realism.

Just as it may be no simple matter to posit the right entities, it may not be evident how to ask the right questions:

The main reason we have had a hard time answering “How many genes cause postzygotic isolation?” should now be clear:  It is not a single question.  Instead, this query masks a large number of questions that may have very different answers.
Jerry Coyne and H. Allen Orr, Speciation  (2004), p. 306

And indeed, the authors conclude:  “There has been nearly endless discussion of species concepts.   This vast and stupefying literature has produced little new or interesting biology.”

[Update 22 March 2012] And indeed … Andrew Hamilton, reviewing Richard A. Richards, The Species Problem: A Philosophical Analysis, Cambridge University Press, 2010, writes:

There are four books on my shelf and countless papers in my electronic and physical files with the title "The Species Problem." Many of these were written by philosophers, but almost as many were written by biologists. …  None of the books and papers on this topic contains anything like a consensus solution.

The reviewer then rejects this latest attempt:

As a solution to 'the' problem or as a theory-based definition, however, Richards' strategy isn't going to work. … While it may be true …  that all contemporary species concepts pick out population-level evolutionary lineages, they do so in different and often incompatible ways. Agreeing that species are lineage segments goes no distance toward helping to find the boundaries or to settle the host of arguments about what boundaries to seek. This approach swaps one hard question (what are species?) for another (what's an evolutionary individual?), as is the case with most or all of the other proposed solutions to date.


Having rejected the solution, I would now like to reject the problem.

That, actually, has pretty much been the history of Anglo-Saxon analytic philosophy, from G. E. Moore on out:  you don’t solve a problem; you unmask it as metaphysical (or some other handy word), and dissolve it.

[Update 26 May 2013]  Even more radically rejectionist is What Darwin Got Wrong (2011), by Jerry Fodor and Massimo Piattelli-Palmarini.

The latter author (who largely wrote the former half) reviews (p. 57) the entities that have been proposed as the axis upon which all selection turns:

Pleas have been made … for revising the traditional neo-Darwinian thinking that either the individual, or the population as a whole, are the sole units of selection.   There are selective processes … also at the level of genes, chromosomes, whole genomes, whole epigenomes, cells, developing tissues, kin groups, societies and communities;  and, of course, organisms and populations.

(Notice that he doesn’t even mention “species”, as in The Origin of Species, yo?)

The former author, laying about him with a broadsword, writes (p. 126)

Phenotypes aren’t bundles of traits; they’re more like fusions of traits.  Prima facie, the units of phenotypic charge are whole phenotypes.

Compare the famous hyperholistic thrown-gauntlet of Quine: “The unit of empirical significance is the whole of science”.

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