What is a natural kind? As we shall see, the concept of a natural kind has a long history. Many of the interesting doctrines can be detected in Aristotle, were revived by Locke and Leibniz, and have again become fashionable in recent years. Equally there has been agreement about certain paradigm examples: the kinds oak, stickleback and gold are natural kinds, and the kinds table, nation and banknote are not. Sadly agreement does not extend much further. It is impossible to (...) discover a single consistent doctrine in the literature, and different discussions focus on different doctrines without writers or readers being aware of the fact. In this paper I shall attempt to find a defensible distinction between natural and non-natural kinds. (shrink)

Hilary Putnam deals in this book with some of the most fundamental persistent problems in philosophy: the nature of truth, knowledge and rationality. His aim is to break down the fixed categories of thought which have always appeared to define and constrain the permissible solutions to these problems.