In metaphysics, the noumenon is a posited object or event that exists independently of human that noumena and the noumenal world are objects of the highest knowledge, truths, and values is Plato's principal legacy to philosophy. Noumenon, plural Noumena, in the philosophy of Immanuel Kant, the thing-in-itself (das Ding an sich) as opposed to what Kant called the phenomenon—the thing as it appears to an observer. Though the noumenal holds the contents of the intelligible world, Kant claimed that man’s. In the simplest sense, Kant says that there are two different worlds. The first world is called the noumenal world.