SECT.  XLIII.  Of the Soul, which alone, among all Creatures, Thinks and Knows.

But the body of man, which appears to be the masterpiece of nature, is not to be compared to his thought.  It is certain that there are bodies that do not think: man, for instance, ascribes no knowledge to stone, wood, or metals, which undoubtedly are bodies.  Nay, it is so natural to believe that matter cannot think, that all unprejudiced men cannot forbear laughing when they hear any one assert that beasts are but mere machines; because they cannot conceive that mere machines can have such knowledge as they pretend to perceive in beasts.  They think it to be like children’s playing, and talking to their puppets, the ascribing any knowledge to mere machines.  Hence it is that the ancients themselves, who knew no real substance but the body, pretended, however, that the soul of a man was a fifth element, or a sort of quintessence without name, unknown here below, indivisible, immutable, and altogether celestial and divine, because they could not conceive that the terrestrial matter of the four elements could think, and know itself: Aristoteles quintam quandam naturam censet esse, è quâ sit mens.  Cogitare enim, et providere, et discere, et docere. . . . in horum quatuor generum nullo inesse putat; quintum genus adhibet vacans nomine.