By any realistic definition naturalism is a religion, and an extremely dogmatic one. It rests on a basic conviction about ultimate reality that is held by a kind of faith, and it incorporates its own definitions of "knowledge" and "reason." It says that knowledge comes ultimately from our senses and that the more complex forms of knowledge come from scientific investigation. By naturalistic definition there can be no such thing as knowledge of the supernatural. Statements about God are either nonrational (if frankly presented as mere subjective belief) or irrational (if they purport to make objective factual claims).