I am a physical object sitting in a physical world. Some of the forces of this physical world impinge on my surfaces. Light rays strike my retinas; molecules bombard my eardrums and fingertips. I strike back, emanating concentic air waves. These waves take the form of torrents of discourses about tables, people, molecules, light rays, retinas, air waves, prime numbers, infinite classes, joy and sorrow, good and evil.

--W. V. O. Quine