§ 104 n. 1. On this subject, see Appendix. ↩
§ 106 n. 1. The notion of class in general, we decided, could be replaced, as an indefinable, by that of the class of propositions defined by a propositional function. ↩
§ 106 n. 2. On this point, however, see Appendix. ↩
The Principles of Mathematics was written by Bertrand Russell, and published in in 1903. It is now available in the Public Domain.