The theory ofdescriptions was designed to meet this and otherdifficulties. One result of the work we have been considering is todethrone mathematics from the lofty place that it hasoccupied since Phythagoras and Plato, and to destroy thepresumption against empiricism which has been derived fromit. In this sense, mathematical knowledge is still notempirical. But it is also not a priori knowledge about theworld. It is, in fact, merely verbal knowledge.
Thusmathematical knowledge ceases to be mysterious.
Physics, as well as pure mathematics, has suppliedmaterial for the philosophy of logical analysis. This hasoccurred especially through the theory of relativity andquantum mechanics. What is important to the philosopher in the theory ofrelativity is the substitution of space-time for space andtime. The choice between these various ways wasarbitrary and no one of them was theoretically preferable toany other. No physicalfacts correspond to these different conventions.