I maintain that any writer of a book is fully authorised in attaching any meaning he likes to a word or phrase he intends to use. If I find an author saying, at the beginning of his book, "Let it be understood that by the word 'black' I shall always mean 'white,' and by the word 'white' I shall always mean 'black,'" I meekly accept his ruling, however injudicious I think it.

Symbolic Logic: Elementary (ed. 1955)