noumenon

noumenon (singular), noumena (plural)

Related to Kantianism, things as they really exist, as opposed to how they are perceived by the human observer. For example, the human observer imposes concepts of time and space on things, though time and space are not intrinsic properties of the world but were created in the mind of the human observer.

Source: Malik, 2000, pp 72

See phenomenon.