ABSTRACT
By “general knowledge” I mean knowledge of the truth or falsehood of sentences containing the word “all” or the word “some” or logical equivalents of these words. The word “some” might be thought to involve less generality than the word “all”, but this would be a mistake. This appears from the fact that the negation of a some-sentence is an all-sentence, and vice-versa. The negation of “some men are immortal” is “all men are mortal”, and the negation of “all men are mortal” is “some men are immortal”. Thus any person who disbelieves a some-sentence must believe an all-sentence, and vice versa.
