D. M. Walsh - Organisms, Agency, and Evolution

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D. M. Walsh 2015

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First published 2015

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For Margaret OMalley

When I took my first ethology course, I was instructed to make an ethogram. An ethogram is a catalogue of the movements, postures and sounds of a target organism whose behaviour one wishes to study. The objective of the ethogram is to free the observation of behaviour from any taint of purpose or intention. We were to identify behaviours with manifestations, rather than motives. I was told that my Columbian Ground Squirrels ( Spermophilus columbianus ) were standing on their hind legs at full height, rather than surveying the scene for predators. They were emitting a high-pitched bark, rather than alerting their fellow colony members to imminent dangers. As a biddable undergraduate, I dutifully went along with this, even though I could see that my squirrels were looking for something, and warning each other. My brush with ethology taught me three things. The first is that midnight black is the best hair-dye tint for painting patterns on ground squirrels. The other two are less practical. They are that organisms are fundamentally purposive entities, and that biologists have an animadversion to purpose. These perplex me: why should the phenomenon that demarcates the domain of biology be off-limits to biology?

This is more than just an idiosyncratic bemusement on my part. It is a leitmotif that runs through the entire history of biology. Since its inception, biology seems to have been torn by the evidently incompatible demands of treating organisms as natural entities, like everything else, and as singularly peculiar (naturally purposive) things, unlike anything else. One of the common strategies has been to attempt to minimise the distinctiveness of organisms, to show that the problematic nature of organisms is incidental to a comprehensive understanding of understanding of biology, and that the principles by which we account for nonliving phenomena are wholly adequate to the explanation of living phenomena. This is a bold move, and it is fair to say that it has paid dividends.

Nowhere is it pursued more vigorously, or more successfully, than in the theory of evolution that descended from Darwins and grew to prominence throughout the twentieth century. The Modern Synthesis theory of evolution is elegant and powerful. Inspired by the molecular revolution in biology, the Modern Synthesis circumvents the organism issue by making genes the canonical unit of biological organisation. Modern Synthesis evolution is a fundamentally molecular phenomenon. It is the process in which a giant molecule, DNA, is replicated, and transmitted from one generation to the next, whereupon it builds entities (vehicles or interactors) that help to spread further replicates.

No one can gainsay the advances in our understanding of biology ushered in by the Modern Synthesis. It is now coming up for a century of unparalleled success. But we are beginning to see intimations that, perhaps, this disorganicised evolutionary thinking may be running up against its limitations. These deficiencies, by my reckoning, occur at just the places where our understanding of evolution could be enhanced by paying attention to the contribution of organisms as organisms.

Whether or not the Modern Synthesis is reaching the end of its useful life, there is ample justification for exploring an alternative. It lies in the fact that Modern Synthesis thinking misrepresents the metaphysics of evolution. Evolution, properly construed, is not so much a molecular phenomenon as an ecological one. It arises out of what organisms do in the pursuit of their ways of life. That, I take it, is the lesson of cardinal importance to be drawn from Darwins Origin of Species . But it is precisely this perspective that has been obscured by the marginalisation of organisms that has taken hold under the Modern Synthesis. I think it is a salutary exercise to contemplate what we might have missed by leaving organisms out of our understanding of evolution. That is the objective of this book.

The book comprises three main parts. explores the consequences of the discovery and intensive concentration on genes that has inspired the growth of twentieth-century biology (and continues to do so). The gene has encouraged what I call the fractionation of evolution. Thanks to gene centrism we can think of the component processes of evolution inheritance, development, adaptive change and the origin of novelties as discrete and autonomous. Together, they comprise evolution. They are united by the fact that the gene is the canonical unit in the explanation of each process.

Fractionation, I think, is the linchpin of Modern Synthesis, gene-centred thinking. It is what undergirds the Modern Synthesis approach to evolution that I call Replicator Biology. If fractionation is right, I reckon, so is Replicator Biology. Fractionation amounts to the great empirical wager of the Modern Synthesis. While fractionation is not usually the explicit target of those who wish to challenge the Modern Synthesis, it is the implications of fractionation that have been most vigorously opposed in recent evolutionary biology and its philosophy.