ABSTRACT
In the whole philosophy o f mathematics, which used to be at least as full o f doubt as any other part o f philosophy, order and certainty have replaced the confusion and hesitation which have formerly reigned. Philosophers, o f course, have not yet discovered this fact, and continue to write on such subjects in the old way. But mathematicians, at least in Italy, have now the power o f treating the principles of mathematics in an exact and masterly manner by means o f which the certainty of mathematics extends also to mathematical philosophy.
