Walsh Group

I am (primarily) a philosopher of biology at the Department of Philosophy and the Institute for the History and Philosophy of Science at the University of Toronto. By biology PhD dissertation research (McGill) was in systematics and evolution. My philosophy PhD dissertation (London) was in metaphysics and modal logic. From 2005 until 2015 I held the Canada Research Chair in Philosophy of Biology. In recent years my research has concentrated on the concept of natural agency. A natural agent, on this view, is any system that can maintain its viability, react and innovate, by mounting adaptive responses to its conditions. My 2015 book Organisms, Agency, and Evolution explored the implications of natural agency for evolution. In particular it outlined a number of ways in which organisms as agents participate in evolution and raised the question whether the Modern Synthesis theory of evolution is capable of assimilating an agential perspective. My current research concentrates on the methodological challenges of studying agency scientifically.


The Paradox of Population Thinking: First Order Causes and Higher Order Effects (2019)

Darwin’s discovery of descent with modification was inaugurated by a shift in perspective that Ernst Mayr (1975) has dubbed “population thinking.” Darwin realized that the explanation of the fit and diversity of organic form should be approached as a question about the constitution of populations. Rather than ask how individual organisms come to acquire their remarkable features—their complexity, their functional integration, their exquisite adaptedness to their conditions of existence—we should ask how populations come to comprise such individuals.

Objectcy and Agency: Toward A Methodological Vitalism (2018)

Organisms are like nothing else in the natural world. They are agents. Methodological vitalism is a view according to which the difference that organisms make to the natural world cannot be captured wholly if we treat them as mere objects. Understanding agency calls for a different kind of theory, an agent theory.

“Chance Caught on the Wing”: Metaphysical Commitment or methodological Artifact? (2017)

Jacques Monod’s Chance and Necessity poses a paradox for modern biology: Organisms both must be and cannot be purposive systems. To resolve the paradox we must explain purpose by appeals to invariance or invariance by appeal to purpose. The methodology of modern science, however, allows no unreduced appeals to purpose. Monod traces the modern synthesis commitment to ineluctable chance back to its animadversion to teleology. He credits the pre- Socratic Atomist philosopher Democritus with holding that everything in the world is the fruit of chance and necessity. It is becoming increasingly obvious that their purposiveness is pivotal to the dynamics of evolution. This chapter outlines a ‘neo-Aristotelian’ alternative to the neo-Democritean commitments of modern synthesis biology, one that accords the purposiveness of organisms a central explanatory role in evolution.

Organisms, Agency, and Evolution (2015)

Walsh, D. M. The central insight of Darwin's Origin of Species is that evolution is an ecological phenomenon, arising from the activities of organisms in the 'struggle for life'. By contrast, the Modern Synthesis theory of evolution, which rose to prominence in the...