1 Neo-Paleyan Biology Tim Lewens University of Cambridge Department of History and Philosophy of Science Free School Lane Cambridge CB2 3RH Email:
[email protected] Abstract There is a ‘Neo-Paleyan’ tradition in British evolutionary theorising, which began with Darwin and continues to the present day. This tradition conceives of adaptation in terms of design, and it often puts natural selection in the role of an ersatz designer. There are significant disanalogies between Paleyan conceptions of design and modern conceptions of adaptation and selection, which help to explain why the neo-Paleyan programme is sometimes treated with hostility. These general disanalogies do not suffice to dismiss the most interesting forms of recent neo-Paleyanism, which draw on theoretical principles such as Fisher’s Fundamental Theorem to ground a general approach to what we can call (following Grafen) the ‘criterion’ of evolutionary design. It is important to distinguish between justifications of this ‘criterion’ and justifications of approaches to nature which presuppose that natural selection produces good designs. 2 Keywords: Adaptation, Andy Gardner, Alan Grafen, Design, Fisher’s Fundamental Theorem, William Paley Funding This work was funded by a grant from the John Templeton Foundation. I am also grateful to the Fondation Maison des Sciences de l’Homme, Paris, for support during the completion of this project. Acknowledgements Earlier versions of this paper were presented in Copenhagen, Oulu and Paris. I am grateful to audiences there, and to the referees from this journal for comments. I am especially grateful to Jean-Baptiste Grodwohl for remarkably detailed and penetrating remarks on the submitted manuscript, and to Andy Gardner, Jonathan Birch and Samir Okasha for additional suggestions for improvements and clarifications.