Mechanistic Evidence: Disambiguating the Russo–Williamson Thesis

Abstract

Russo and Williamson claim that establishing causal claims requires mechanistic and difference-making evidence. In this article, I will argue that Russo and Williamson's formulation of their thesis is multiply ambiguous. I will make three distinctions: mechanistic evidence as type vs object of evidence; what mechanism or mechanisms we want evidence of; and how much evidence of a mechanism we require. I will feed these more precise meanings back into the Russo–Williamson thesis and argue that it is both true and false: two weaker versions of the thesis are worth supporting, while the stronger versions are not. Further, my distinctions are of wider concern because they allow us to make more precise claims about what kinds of evidence are required in particular cases.

Acknowledgements

I am grateful to the Leverhulme Trust for supporting this research. I am also indebted to colleagues at Kent and in the Causality in the Sciences network for discussion of many of these issues. Particular thanks are due to Lorenzo Casini, Brendan Clarke, Donald Gillies, Federica Russo, Attilia Ruzzene, and Jon Williamson. I am grateful to two anonymous referees of this journal for constructive criticism. Remaining errors are, of course, my own.

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Notes on contributors

Phyllis McKay Illari

Phyllis McKay Illari is at the Department of Philosophy, University of Kent.