Paul Guyer's paper "Naturalistic and Transcendental Moments in Kant's Moral Philosophy" raises a set of issues about how Kantian ethics should be understood in relation to present day "philosophical naturalism" that are very much in need of discussion. The paper itself is challenging, even in some respects iconoclastic, and provides a highly welcome provocation to raise in new ways some basic questions about what Kantian ethics is and what it ought to be. Guyer offers us an admirably informed and complex (...) argument, both historical and philosophical, that tangles with some of the most difficult problems in Kant's moral philosophy. It begins with some ambitious and controversial claims about Kant's moral philosophy prior to the Groundwork of 1785. It then offers an interpretation, and also a fundamental criticism, of the Groundwork's attempt to establish the moral law based on the idea of freedom of the will. And finally, it raises - and expresses some opinions on - the large and vexed questions of the relationship between transcendental philosophy and philosophical naturalism, and whether Kantian ethics can be made consistent with a naturalistic philosophical outlook. In these comments I will have something to say on each of these three topics, without pretending (any more than Guyer does) to have exhausted what might be said about them. (shrink)