The three main medieval points of view regarding universals are designated by historians as realism, conceptualism, and nominalism. Essentially these same three doctrines reappear in twentieth-century surveys of the philosophy of mathematics under the new names logicism, intuitionism, and formalism.

It is one of the consolations of philosophy that the benefit of showing how to dispense with a concept does not hinge on dispensing with it.

Treating 'water' as a name of a single scattered object is not intended to enable us to dispense with general terms and plurality of reference. Scatter is in fact an inconsequential detail.

If there is a case for mental events and mental states, it must be that the positing of them, like the positing of molecules, hassome indirect systematic efficacy in the development of theory.

We do not learn first what to talk about and then what to say about it.

Logic is an old subject, and since 1879 it has been a great one.

To call a posit a posit is not to patronize it. A posit can be unavoidable except at the cost of other no less artificial expedients. Everything to which we concede existence is a posit from the standpoint of a description of the theory-building process, and simultaneously real from the standpoint of the theory that is being built.