Aristotle (384–322 BCE)

For the Greek philosopher Aristotle, the most prominent disciple of Plato and founder of the so-called Peripatetic School, time is one of the fundamental constituents of reality. In his Categories he refers to time—without further discussing it here—as one out of ten “kinds of being,” as “when” (pote). As a continuous quantity next to place and line, surface and body, time, for Aristotle, pertains to the category of quantity (poson). In Physics, however, he uses the concept of time in juxtaposition with the concepts of nature (physis), motion (kinesis), place (topos), infinity (apeiron), continuum (syneches), and emptiness (kenon) as a fundamental concept of his philosophy of nature. And although in the logic founded by him, time is of no concern to Aristotle (a “temporal logic” still being a far cry), it is the implicit horizon of human decisions and actions in his ethics. Unlike in modern philosophy, in which it figures as an eminent subject, time, for Aristode, is merely an “accident” of reality, inasmuch as this latter is grouped around the concept of substance (ousia). Thus, on the one hand, all categories outside of the substance number among the accidents. On the other, just as motion and quiet, the number—and with it time—belongs to that which is “generally perceptible” (koina aistheta) in the phenomena, that is to say to that which is not restricted to a specific sense such as smelling or hearing but that belongs to all perceptions in general. Although they are, as a matter of consequence, universal constituents of humans' experience of reality, these categories exist in themselves merely as accidental qualities of a substance in motion.

Nevertheless, Aristotle's treatise on time in Physics (IV 10–14) is indubitably one of the most elaborate and influential contributions to the clarification of the essence of time. It evidendy does not allow the inclusion of time in a metaphysical system, as that was later accomplished by the founder of Neoplatonism, Plotinus. Already the early critics such as the pre-Christian Peripatetics and the Neoplatonic commentators of Aristotle therefore object less to his phenomenological analyses than both to the fundamental lack of clarity with regard to the metaphysical status of time—that is, more precisely, of its definition as number and measure—and to the function performed by the soul in measuring and perceiving time. The judgment passed on Aristode's analysis of time by modern critics has to be seen, for the most part, in the light of their own theories of time, some of which take their origin from the aporiae of the Aristotelian text. For Henri [Page 49]Bergson, Aristotle is the first philosopher to have spatialized time and to whose concept of time Bergson opposes his concept of duration (durée). Martin Heidegger, on the foil of his existential-on-tological concept of temporality (Zeitlichkeit), regards Aristode as the exponent of a “vulgar” concept of time whose characteristics are timekeeping, the use of clocks, and the “uninterrupted and unbroken succession of the now” (Heidegger, 1988, §19). Modern characterizations of Aristotle's theory of time range from “the first philosophical theory of measuring time” (Janich, 1985) to “the phenomenology of the ordinary conception of time” (Wieland, 1992, p. 334; translation by entry author).

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