Natural (or naïve) realism reflects the organism’s faith in the literal truth of cognition. Through projection, the brain’s real-time simulation of the external world is normally and transparently experienced as the world. We experience the world out there and not inside our skulls or on the sensory surfaces of the body. Natural idealism is a complementary phenomenon that does the opposite. It intuits that the true essence of experienced reality consists in ideas, thoughts, or perceptions rather than “material” things. While appearing to be contrary, natural idealism employs similar processes of abstraction, reification, and projection. It is as natural for us to credit ideas and abstractions with reality as to credit sense impressions. Just as natural realism is the basis for the realism of science, so natural idealism is the basis of philosophical idealism, such as held by Plato or Berkeley, for example. Both realism and idealism are assertions of what is “real.” (Which is why mathematical Platonism is sometimes called mathematical realism.)