This book is about the methods used for unifying different scientific theories under one all-embracing theory. The process has characterized much of the history of science and is prominent in contemporary physics; the search for a 'theory of everything' involves the same attempt at unification. Margaret Morrison argues that, contrary to popular philosophical views, unification and explanation often have little to do with each other. The mechanisms that facilitate unification are not those that enable us to explain how or why phenomena behave as they do. A feature of this book is an account of many case studies of theory unification in nineteenth- and twentieth-century physics and of how evolution by natural selection and Mendelian genetics were unified into what we now term evolutionary genetics.

"Unifying Scientific Theories offers an exemplar of the historical and philosophical breadth that are important and badly needed in philosophical attempts to understand the many faces of unity in science." Andrew Wayne, Canadian Journal of Philosophy

"I expect this book to have a truly significant impact on today's philosophy of science. My reasons are three: it is solidly grounded in the history of science, it addresses biology as well as the physical sciences, and it represents a tremendous challenge to much contemporary thinking about scientific explanation." Bas van Fraassen, author of The Scientific Image

"a sustained, informative, and thought-provoking"