19. Truth or falsehood always supposes affirmation or negation.
Though, in compliance with the ordinary way of
speaking, I have shown in what sense and upon what ground our ideas may be sometimes called true or false; yet
if we will look a little nearer into the matter, in all cases where any idea is called true or false, it is from some
judgment that the mind makes, or is supposed to make, that is true or false. For truth or falsehood, being never
without some affirmation or negation, express or tacit, it is not to be found but where signs are joined or
separated, according to the agreement or disagreement of the things they stand for. The signs we chiefly use are
either ideas or words; wherewith we make either mental or verbal propositions. Truth lies in so joining or
separating these representatives, as the things they stand for do in themselves agree or disagree; and falsehood in
the contrary, as shall be more fully shown hereafter.