Every theory in philosophy, which is built on pure conjecture, is an elephant; and every theory that is supported partly by fact, and partly by conjecture, is like Nebuchadnezzar's image, whose feet were partly of iron, and partly of clay.
Thomas ReidThe rules of navigation never navigated a ship. The rules of architecture never built a house.
Thomas ReidIt is a question of fact, whether the influence of motives be fixed by laws of nature, so that they shall always have the same effect in the same circumstances.
Thomas ReidA philosopher is, no doubt, entitled to examine even those distinctions that are to be found in the structure of all languages... in that case, such a distinction may be imputed to a vulgar error, which ought to be corrected in philosophy.
Thomas Reid