§ 120 n. 1. Except Frege's Grundgesetze der Arithmetik (Jena, 1893). ↩

§ 120 n. 2. F. 1901, Part II and F. 1899, § 20 ff. F. 1901 differs from earlier editions in making number is a class

a primitive proposition. I regard this as unnecessary, since it is implied by 0 is a number.

I therefore follow the earlier editions. ↩

§ 120 n. 3. Throughout the rest of this chapter, I shall use *number* as synonymous with *finite integer*. ↩

§ 121 n. 1. F. 1899, p. 30 ↩

The Principles of Mathematics was written by Bertrand Russell, and published in in 1903. It is now available in the Public Domain.