Metaphysics is the nature of reality, the world we live in, and the first branch of a complete system of philosophy. What is the nature of reality? Reality is the world we live in and what we perceive when we use our five senses: seeing, hearing, smelling, feeling, and tasting. Existence is all around us. Nature operates according to natural laws, like the Law of Identity and the Law of Cause and Effect. Things are what they are, and we determine what is true by the context of our knowledge of nature. The first branch of philosophy answers the very first question of existence: What is it? It is what it is.