Principle of individuation

The Principle of individuation defines the strict identity that objects have in perception and reveals why an imaged object does not conform to the same standard. A perceived thing is fixed in time and space, has determinate qualities, and cannot be itself and something else at once in the same relation; an image, by contrast, may contract a duration and combine aspects that no single instant could contain.

Definition and Scope

In perception, a thing is given as what it is: its position in time and space is strictly defined, its qualities are determinate, and its identity excludes being something else at the same time and in the same respect. These conditions together express the Principle of individuation. Knowledge directed toward an object may select one of its aspects, but it still aims at that object—or a class of objects—as one and identical. It much less commonly aims at the object as a unique appearance confined to an indivisible moment.

The Imaged Object and Duration

An imaged object only imperfectly meets the conditions of individuation. Whether the image arises in consciousness of a picture, in imitation, or in a hypnagogic image, it does not present the object under an instantaneous aspect. Knowledge may aim at Pierre through features such as his red cheeks and cheerful smile, but the Pierre of the mental image is a synthesis that contracts a duration, sometimes including contradictory aspects. The image can therefore retain its power to move someone long after the person in the flesh has lost that power.

Identity, Knowledge, and Affectivity

The image’s failure to individuate a single appearance does not mean that knowledge loses its object: knowledge and affectivity can agree about an aspect while differing about the object’s identity or temporal range. For example, knowledge may aim at Pierre as seen that morning, while affectivity presents him through an image shaped by how he has appeared over the preceding week. Because these intentions fuse in the imaging consciousness, features associated with different moments can be given as belonging to the same Pierre. The Principle of individuation thus marks a tension between the object’s stable identity and the image’s capacity to gather a temporally extended, emotionally inflected synthesis.