The biological functions debate is a perennial topic in the philosophy of science. In the first full-length account of the nature and importance of biological functions for many years, Justin Garson presents an innovative new theory, the 'generalized selected effects theory of function', which seamlessly integrates evolutionary and developmental perspectives on biological functions. He develops the implications of the theory for contemporary debates in the philosophy of mind, the philosophy of medicine and psychiatry, the philosophy of biology, and biology itself, addressing issues ranging from the nature of mental representation to our understanding of the function of the human genome. Clear, jargon-free, and engagingly written, with accessible examples and explanatory diagrams to illustrate the discussion, his book will be highly valuable for readers across philosophical and scientific disciplines.

'Biological functions are much discussed but little understood. Justin Garson appeals to the explanatory depth of functional explanations to develop a powerful general theory of functions. This book will serve as a reference point for future debate.'

David Papineau - King's College London

'Garson does a superb job of explaining just how central a philosophical understanding of functions is to a wide array of discussions in philosophy and science. These discussions include how to count junk DNA in the ENCODE project, how to classify traits and individuate mechanisms, how different kinds and levels of biological explanations relate to each other, the nature of health and disease, the nature of mental disorder, and even the fundamental basis of thought itself. In addition to being an excellent introduction to these issues, this book gives us a fresh, lively and comprehensive presentation of Garson’s distinctive contributions.'

Karen Neander - Duke University, North Carolina

‘[In] What Biological Functions Are and Why They Matter, Justin Garson formulates the major philosophical issues that a relevant theory of function should solve as three main puzzles, namely (1) the function/accident distinction, (2) dysfunction, and (3) the etiological explanatory value of function.’

Etienne Roux Source: Metascience