Lamarck's "Philosophie Zoologique" (2008.12.1[Mon])

 

I've written about how the standard account of the evolution of the controversy surrounding the theory of evolution goes something like, "Cuvier refuted Lamarck, and Darwin refuted Cuvier." Most people have an image of Lamarck, who predated Cuvier and his anti-evolutionary catastrophism, as no more than a relic from the 1700s, but surprisingly that is not the case. Lamarck was in fact nearer to Darwin's thought, even to ours for that matter. In the 50 years between the publication of his "Philosophie Zoologique" and Darwin's appearance onstage, Cuvier was the sole figure impeding the evolution of evolutionary theory. I have already discussed how the upheaval of the French Revolution and other factors contributed to this. Koizumi and Yamada's 1954 translation of "Philosophie Zoologique" (Iwanami Bunko) will serve as the base reference for this column. Makoto Koizumi, one of the translators, himself made important contributions in the dawn of evolutionary studies in Japan and his review is also worth reading.

    The study of how this world we live is put together, the basis of our view of nature itself, is an ancient one, with the earliest taxonomical classification of animals and plants dating back to Aristotle. Theories of nature were no more than a component of different religious worldviews until advances made in the 17th and 18th centuries brought new precision to the study of natural history. As this discipline took on a life of its own, theories of evolution became more scientific, bringing them inevitably into conflict with various articles of faith, at about the same time as I see the beginnings of a rift between science and natural history emerge, with Darwin striking the final blow. Of course, looked at from this historical perspective, Darwin is no more than a character who appears only on the final page of the story, and the inevitably many scholarly disputations that led up to that denouement tend to be overlooked. Among these is "Philosophie Zoologique," a work that does much to free us from Cuvier's bedazzling influence and see Lamarck in a new light.

    This work was first published in 1809 (almost exactly 200 years ago), and it exemplifies the thought of the latter half of the 18th century, in which the natural world was ranked and filed according to a scala naturae of all beings from the humblest worm to the angels and god. What Lamarck did was to revise this taxonomy based on morphological evidence (abandoning Aristotle's system in the process) and, noting how the different lineages changed over the ages, proposed his theories of "use and disuse" and "the inheritance of acquired traits."

    The opening section on deity is cringeworthy and unpromising, but thankfully occupies no more than a few pages. God is subsequently banished from the book, never to reappear, replaced by an anthropomorphic Nature when grammar calls for an almighty subject. As the translators of the book suggest, this is a bit of verbal legerdemain, to conceal Lamarck's lack of belief in a creator with human characteristics. Something to keep the papal censors appeased. This was still 50 years prior to Pasteur's rejection of spontaneous generation, and for Lamarck it was not unnatural to conceive of the lowest forms of life as continually emerging forth from a nonliving ferment. Lamarck's dismissal of divine intervention stands in telling contrast to Darwin, who never entirely relinquished the role of a Creator in his "Origin of Species*1" 50 years later. To my knowledge Haeckel is the only one of the 19th century thinkers who spun the evolutionary theory together to take a rational position on the emergence of life as something that is likely simply the result of some unknown, complex physiochemical processes, but considering the scientific milieu of the earliest part of that century, Lamarck's views were also quite reasonable, and if anything Darwin's were the more contaminated with deistic voodoo.

    Lamarck arranged animals into 14 groups, each of which include lineages determined by bodily differences. In essence, it was a cladistic approach. By giving rise to structural improvements (what we call innovations or novelties), Lamarck's evolution could bring forth new animals that had never before existed, and thus to new taxa. In this sense, the "Philosophie Zoologique" represents an evolutionary history viewed through the lens of changes in body plans, which is notably missing from the "Origin of Species." And although he began with a vision of a single ladder-like path, Lamarck's thinking led him inexorably to a more dendriform phylogeny.

    So although he may not have bruited it too boldly about, Lamarck had rejected the Aristotelian chain of being well before Darwin's day. The difference between Darwin's and Lamarck's systems is generally portrayed as the difference between a ramified view of speciation and one that features stepwise transitions, but this too was not necessarily the case, and given Darwin's weakness in the understanding of morphology, one might justifiably say that Lamarck was closer in his approach to the modern evo-devo ideas of the roles of form and development in the evolutionary process. Rejecting God, Aristotle and the scala naturae, Lamarck gave us a theory of animal evolution based on Bauplan transitions, and did it at the turn of the 19th century. Haeckel knowingly used this same grand style as a template for his own "Die Natürliche Schöpfungsgeschichte" (The History of Creation*2).

    This leaves us with a problem. Although Haeckel, father of the recapitulation theory, may group Goethe and Darwin into a single lineage, many evolutionary scholars would shudder at including Lamarck, solely due to his authorship of the theory of acquired traits. But Darwin himself never fully ruled out the possibility. Certainly natural selection would work to sift out desuetudinous body parts, as predicted in the theory of use and disuse. And it is equally evident that features evolve because of their utility. There is little difference in Darwin's survival of the fittest, which itself is based on the tautological argument that whatever has survived selection is what now exists. The Baldwin effect and gene assimilation are among the not infrequent examples of how acquired characteristics indeed appear as if they are heritable. Of course, that is not to say that this can form the basis of an organizing principle. But Darwin proposed gemmules, hypothetical liquid factors in the blood, as the physical basis for his own system of natural selection, and we now know this to be wrong as well. Darwin needs to be distinguished from Darwinism. And just as importantly, it needs to be remembered that it was Germans and French scientists such as Haeckel and Lamarck, with their groundbreaking work in the comparative embryology, histology and anatomy that Darwin so dreaded, who gave flesh and bones to the conceptual framework of evolution he proposed.

    The "Philosophie Zoologique" is required reading. Lamarck so rarely sees the light of day anymore, so this book is a must in order to gain a truer appreciation of his accomplishment. Unaware of the seismic changes that we have seen in modern genetics and continental drift, Darwin himself wrote scads of nonsense in "The Origin of Species" about biological geography and husbandry that the contemporary reader can only find objectionable. But "Philosophie Zoologique" is full of stimulating insights into evolution. It is a book that reveals just how near the thoughts of one genius working at the dawn of the 19th century were to our own system of knowledge.