When two names are joined together into a consequence, or affirmation, as thus, “a man is a living creature”; or thus, “if he be a man, he is a living creature”; if the latter name, “living creature,” signify all that the former name “man” signifieth, then the affirmation, or consequence, is “true”; otherwise “false.” For “true” and “false” are attributes of speech, not of things. And where speech is not, there is neither “truth” nor “falsehood”; “error” there may be, as when we expect that which shall not be, or suspect what has not been; but in neither case can a man be charged with untruth.

Seeing then that truth consisteth in the right ordering of names in our affirmations, a man that seeketh precise truth had need to remember what every name he uses stands for, and to place it accordingly, or else he will find himself entangled in words, as a bird in lime twigs, the more he struggles the more belimed. And therefore in geometry, which is the only science that it hath pleased God hitherto to bestow on mankind, men begin at settling the significations of their words; which settling of significations they call “definitions,” and place them in the beginning of their reckoning.