- Condition of possibility
A condition of possibility is a necessary framework for the possible appearance of a given list of entities. It is often used in contrast to the unilateral causality concept, or even to the notion of interaction. For example, consider a cube made by an artisan. All cubes are three-dimensional. If an object is three-dimensional, then it is an extended object. But extension is an impossibility without space. Therefore space is a condition of possibility because it is a necessary condition for the existence of cubes to be possible. Note, however, that space did not cause the cube, but that the artisan did, and that the cube and space are distinct entities, so space isn’t part of the definition of cube.
Gilles Deleuze presented it as a dichotomy in contradistinction to the classical phenomenon/noumenon dichotomy. From Plato to Descartes, what was presented by the senses was deemed illusory and denigrated. It was believed that the perceptions ought to be overcome to grasp the thing-in-itself, the essential essence, ala Plato’s allegory of the cave. With Kant comes a transition in philosophy from this dichotomy to the dichotomy of the apparition/conditions-of-appearance. There is no longer any higher essence behind the apparition. It is what it is, a brute fact, and what one must now examine is the conditions that are necessary for its appearance. Immanuel Kant does just this in the Transcendental Aesthetic, when he examines the necessary conditions for the synthetic a priori cognition of mathematics. But Kant was a transition, so he still maintains the phenomenon/noumenon dichotomy, but the noumenon has already been relegated unknowable and to be ignored.
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