§ 81 n. 1. See § 96. ↩
§ 83 n. 1. It is necessary to assign some meaning (other than a proposition) to aRb when R is not a relation. ↩
§ 83 n. 2. A propositional function, though for every value of the variable it is true or false, is not itself true or false, being what is denoted by any proposition of the type in question,
which is not itself a proposition. ↩
The Principles of Mathematics was written by Bertrand Russell, and published in in 1903. It is now available in the Public Domain.