I started on the work that led to this book because there were many aspects of Kant's moral philosophy that I could not understand. I thought that I would have a better chance of understanding them if I knew what questions Kant believed he had to answer when he began considering the subject. In earlier work on Sidgwick, I had found some help in history. I came to think that the history of moral philosophy is not a seamless carpet stretching uninterruptedly from Socrates to us. I thought I could locate a point in that history of which it made sense to say: here is a largely new set of issues from which there developed the specific problems that Sidgwick addressed. Sidgwick seemed more comprehensible to me when I knew what he was trying to do in his philosophizing. I thought there must be counterparts for Kant. This book comes from my attempt to find them.

In 1976 I read Josef Schmucker's Die Ursprünge der Ethik Kants. Although published in 1961 it had not then – it has not yet – been reviewed in English. Schmucker supersedes almost all previous work on the origins of Kant's ethics. I found his studies of the ethics of Wolff and Crusius a revelation, and I remain greatly indebted to his book. But even he did not answer all my questions.