Temporalità e kairòs come caratteri costitutivi della vita biologica nel pensiero di Aristotele

According to Aristotle, living beings are a subgenus of the macro-genus of natural beings (Phys. 192 b 9-10). Natural beings (he thinks) bear an essential relation to change: their nature-essence is an intrinsic principle of change (Phys. II 1). Since change and movement must necessarily occur in time (Phys. IV), the crucial connection between movement and essence(s) of natural beings implies an equally crucial connection between time and these essences. While much has been written about the relation of natural beings to time in Aristotle’s thought, relatively little attention has been paid to the way in which temporality shapes the ways of being of living beings. I will here ask the following question: which kind of relation to time is presupposed, for living beings, by their essences? My hypothesis is that what distinguishes the living relation to temporality from non-living one is that the living one is ruled by a form which dictates a necessary succession of phases, from birth to death. Each phase is a focal moment of the life of the living being: i.e. of the manifestation and appearance, in the concrete life, of the various temporal aspects of its essence, each in its proper moment (kairos).