“Physis,” the Greek word commonly translated “nature,” is derived from the root phy- by the addition of the nominal suffix -sis. “Physis” is connected with phyein “make to grow,” phyesthai “grow,” ho phus “offspring,” and to phyton “plant.” In view of these affinities, “physis” might be taken to mean radically, “growing,” “growth,” or “principle of growth.” The root pity-, however, which is cognate with the Sanskrit bhu- “be, become,” the Latin fui and fieri, and the English “be,” seems able to bear the more basic meaning “be.” “Physis,” accordingly, can mean “being,” or, with a somewhat abstractive force, “beingness”—”the intrinsic constitution of a thing,” its “nature” in this still quite familiar sense.
When “physis” occurs in the pre-Socratic fragments it often appears to have this meaning. Cf. Heraclitus fr. 1, fr. 106; Parmenides fr. 16; Empedocles fr. 63; possibly Parmenides fr. 10 and Empedocles fr. 8. In some instances “physis,” while retaining the basic meaning of intrinsic constitution, beingness, seems also to carry the notion of matter, stuff. This is not strange since the pre-Socratics knew only, and were dealing only with, material being. On occasion it seems to mean birth or generation (as perhaps in the latter two fragments).1
Plato frequently uses “physis” in the sense of beingness or intrinsic constitution. Cf. e.g., Rep. 525c; Philebus, 44e; Politicus, 269d; Sophist, 265a; Parmenides, 132d.
Aristotle, in Metaph. Delta, 4, 1014b16-1015a19, surveys five meanings of “physis,” meanings connected with coming to be, growth, principle of growth, and ousia (beingness, entity), and offers his own definition, which contains elements of all the preceding meanings, in the form of a conclusion: “From what has been said, physis first and properly so called is the ousia of those things which have in themselves, as themselves, a source of movement.” Aristotle was not interested in startling etymological tricks, or in definitions which would altogether subvert common meanings. Both the five listed meanings and the synthetic meaning arrived at in the end must have had a firm basis in Greek usage up to his time.
It seems plausible to combine the above definition with two definitions of “physis” in the Physics: “… physis is a certain source and cause of being moved and being at rest in that to which it belongs first, according to itself and not accidentally …” (Phys. II, 1, 192b21-23); and: “… physis could be the morphe and eidos of those things which have in themselves a source of motion . . (ibid., 193b4-5). Thus Aristotle’s meaning is that physis is the ousia, that is, the form, that is, the intrinsic source of movement, of such things as have an intrinsic source of movement. Ousia, form, and source of movement are in the case of these things identical.
Aristotle’s definition welds together the “being” and “growth” meanings of “physis.” While the etymologically first meaning may be equivalent to “ousia” itself, the philosophic outlook of the pre-Socratics had already restricted “physis” to material things. “Physis” also had meanings associated with those of phyesthai, as “grow,” and, by extension “become.” Aristotle’s contribution, philosophic rather than etymological, was the realization that the ousia of a changeable, material thing is its intrinsic principle of “growth,” or movement.
After Aristotle, “physis” would primarily connote the beingness, the reality of material things, especially of those which grow and reproduce, but by extension, of all those which change, with a disposition to treat that beingness as a source of growth and change. This, presumably, would be the meaning, or complex of meanings, which “physis” would evoke originally for Plotinus and his hearers.
The “collective” sense of nature is, however, occasionally in evidence, as in Aristotle’s doctrine of the unmoved movent: “From such a principle, then, depend the heavens and (the world of) nature” (Metaph. Lambda, 7,1072b 13—14). Also, “physis” can have the more general meaning of the “beingness,” the “nature” of anything, as when in Metaph. Gamma, 2,1003a33-b6 he speaks of “the nature of being.”
Cf. Joseph Owens, “Our Knowledge of Nature,” in Proceedings of the American Catholic Philosophical Association, XXIX (1955), pp. 63-64; G.S. Kirk, Heraclitus, the Cosmic Fragments (Cambridge, England, 1954), p. 228. ↩