Note (return) — Chapter XIII

The two great principles of nature are a vacuum, and a plenum. The plenum is body, or tangible nature; the vacuum is space, or intangible nature. "We know by the evidences of the senses (which are our only rule of reasoning) that bodies have a real existence, and we infer from the evidence of the senses that the vacuum has a real existence; for if space have no real existence, there would be nothing in which bodies can move, as we see they really do move. Let us add to this reflection that one can not conceive, either in virtue of perception, or of any analogy founded on perception, any general quality peculiar to all beings, which is not either an attribute, or an accident, of the body or of the vacuum." 790