Evolving Thoughts

Evolution, culture, philosophy and chocolate! John Wilkins' continuing struggle to come to terms with impermanence... "Humanus sum, nihil humanum a me alienum puto" - Terence

Monday, December 06, 2004

The history of "species"

It occurs (was pointed out) to me that I have talked about everything but what I did my thesis on. So you must now suffer...

I make two historical claims, and a philosophical one. The philosophical one has been published, and is on my website (go to Published Papers) and so we can leave it for now that I think the general meaning of "species" is, and always has been, "differentiated lineage".

The historical claims are this:

1. The Received View that prior to Darwin or modern biology, biological species were essentialistic is historically false. While an essentialistic notion of logical species was the default opinion from Aristotle onwards, even he allowed that living beings would vary "the more and the less" from the logical type. Instead, contrary to Mayr's historical revisionism, typology was generally not essentialistic, as Polly Winsor is demonstrating in paper after paper these days.

Winsor, Mary Pickard. 2001. Cain on Linnaeus: the scientist-historian as unanalysed entity. Studies in the History and Philosophy of the Biological and Biomedical Sciences 32 (2):239-254.
———. 2003. Non-essentialist methods in pre-Darwinian taxonomy. Biology & Philosophy 18:387-400.
———. 2004. Setting up milestones: Sneath on Adanson and Mayr on Darwin. In Milestones in Systematics: Essays from a symposium held within the 3rd Systematics Association Biennial Meeting, September 2001, edited by D. M. Williams and P. L. Forey. London: Systematics Association.

In fact, it appears to me, on the basis of a little sampling, that essentialism in biology arises after Darwin, and in reaction to him. I have found examples in Catholic texts published around 1890. Possibly this is part of a Thomist revival in biology at a time when the Catholic Church had proscribed transmutationism (which was not its traditional view anyway). This was taken up and discussed (and dismissed) by HWB Joseph's Introduction to Logic, first edition 1906, second 1916.

Joseph, H. W. B. 1916. An introduction to logic. 2nd ed. Oxford: Clarendon Press.

Possibly this found its way into the discussions of the species concept and systematics in general at the early part of the 20th century, thence into Stresemann's book

Stresemann, Erwin. 1975. Ornithology from Aristotle to the present. Translated by H. J. Epstein and C. Epstein. Cambridge MA: Harvard University Press.

Stresemann wrote this during the second world war. He was Mayr's teacher before the latter made his way to America.

2. That there always was what I am calling a generative conception of species. It is implicit in Aristotle, but the best example is found in Epicurus' philosophy. I shall quote from Lucretius' On the Nature of Things to illustrate:
If things could be created out of nothing, any kind of things could be produced from any source. In the first place, men could spring from the sea, squamous fish from the ground, and birds could be hatched from the sky; cattle and other farm animals, and every kind of wild beast, would bear young of unpredictable species, and would make their home in cultivated and barren parts without discrimination. Moreover, the same fruits would not invariably grow on the same trees, but would change: any tree could bear any fruit. Seeing that there would be no elements with the capacity to generate each kind of thing, how could creatures constantly have a fixed mother? But, as it is, because all are formed from fixed seeds, each is born and issues out into the shores of light only from a source where the right ultimate particles exist. And this explains why all things cannot be produced from all things: any given thing possesses a distinct creative capacity.
(Lucretius 1969: 38, Book I. 155-191)

Lucretius. 1969. On the nature of things (De rerum natura). Translated by M. F. Smith. London: Sphere Books.

The consistent elements of the generative conception are that form is reproduced consistently. It often has a sexual element, and so it is a kind of Biological Species Concept, despite Mayr's claim that this was not discovered until the 20thC and perfected by him. Almost everywhere you look, in naturalists or philosophers, the generative conception is a consistent thread running from that day to this. It is in John Ray, Linnaeus, Buffon, Lamarck, the 19th century naturalists, in Mill, in Locke and so forth.

There is a consistent tendency in science to see only that which has contributed to the current consensus, and to over-estmiate the originality of modern work. Mayr's is an egregious example, but he is not alone; on this subject alone, Simpson, Cain and others have all roughly committed the same mistake under the Received View. And it exists in other sciences. It derives, I believe, from the fact that science has different exigencies and interests than historical research (let's not get into whether history is a science or not. It is, and it is not. Leave it there).