A term especially associated with Kant, denoting things as they are in themselves, as opposed to things as they are for us, knowable by the senses ( phenomena ). The noumenal lies behind the mind-imposed forms of time, space, and causation, and is therefore unknowable. On one view Kant is locked into a ‘two-worlds’ view, so that the noumenal is rather like Berkeley's God, in being responsible for the phenomenal world, except that we cannot know anything of its nature. On a different view, the distinction merely reflects Kant's understanding that all knowledge is knowledge from a standpoint, so the noumenal is the fraudulent idea of that which would be apprehended by a being with no point of view. It is unclear how on Kant's own view we can mean anything by the term, but Kant does suppose that we need to postulate a noumenal reality and especially a noumenal self as a condition of human free will, the phenomenal self being all too determined in its actions.
Philosophy dictionary. Academic. 2011.