Aristotle on Perceptual Delay

Abstract Aristotle records cases of perceptual delay (a trireme’s oars raised before their sound reaches the shore) but does not see what they cost his theory of perception. Three of his commitments cannot all be maintained: that perception is of what is temporally present, that perceptible qualities are inseparable from their substances, and that perception requires a medium rather than direct contact. Two are ruled out; only Temporal Presence is open to revision. The revised principle, Causal Presence, holds that we perceive what was present when the process began, provided the medium’s current state is the proximate cause. The mechanism draws on a distinction in Physics 3.3, not previously applied to perceptual delay, between an actuality that belongs to one subject but occurs in another. The actuality of being perceived belongs to the object but occurs in the perceiver; the argument holds even where the perceived object no longer exists.