In epistemology, presuppositions relate to a belief system, or Weltanschauung, and are required for it to make sense. A variety of Christian apologetics, called presuppositional apologetics, argues that the existence or non-existence of God is the basic presupposition of all human thought, and that all men arrive at a worldview which is ultimately determined by the theology they presuppose. Evidence and arguments are only marshalled after the fact in an attempt to justify the theological assumptions already made. According to this view, it is impossible to demonstrate the existence of God unless one presupposes that God exists; modern science is incapable of discovering the supernatural because it relies on methodological naturalism and thereby fashions a Procrustean bed which rejects any observation which would disprove the naturalistic assumption. Apologists argue that the resulting worldview is inconsistent with itself and therefore irrational (for example, via the Argument from morality or via the Transcendental argument for the existence of God).