  Quine’s philosophical thought is remarkably consistent over the course of his long working life. There are developments, of course, but outright changes of mind are relatively rare and mostly on relatively minor points. We can, for the most part, treat him as having a single philosophical orientation, to which what he calls “naturalism” is fundamental. This is not to say that his naturalism is self-conscious and explicit from the start; it is, rather, something that he became clearer about over the years. (For the development of Quine’s naturalism, see Verhaegh, 2018.)