 In this connection it is appropriate to note that Aristotle does in fact use the expressions “prime matter” (prôtê hulê) and “primary underlying thing” (prôton hupokeimenon) several times: Physics i 9, 192a31, ii 1, 193a10 and 193a29; Metaphysics v 4, 1014b32 and 1015a7–10, v 6, 1017a5–6, viii 4, 1044a23, ix 7, 1049a24–7; Generation of Animals i 20, 729a32. The mere fact that he uses the phrase is inconclusive, however, since, he makes it explicit that “prime matter” can refer either to a thing’s proximate matter or to whatever ultimately makes it up: 