On Metaphysics

Metaphysics, as defined by the great Immanuel Kant, is the study of reality as it is, not as it appears. In short, it's philosophy for the skeptics and the 'I-told-you-so's.' A branch of philosophy that's all about understanding the underlying nature of existence, and the things that aren't really there.

According to Kant, "the thing in itself" (the 'noumenon') is the thing that exists independently of our perception, whereas the 'phenomenon' is the thing as it appears to us. It's like the difference between a tree and a tree-shaped-cloud.

Want more? Check out Heidegger on Being or Plato on Forms.