It might seem that Descartes' appeal to God in Meditation 4 as a guarantee that for the most part our memories can be trusted is not well-founded. By looking at the question of last-minute creation, a solution is proposed. Can we prove that we and our memories did not all come into existence just five minutes ago, or – as creationists have suggested – that the world and all its fossils did not just come into existence in 4004 BCE? Last-minute creation fantasies raise scenarios that are merely logically possible, but are not compatible with our best theories in geology, biology and other sciences. Descartes' appeal to God faces a different challenge, and objections to it are removed once the logic of his argument is made clear. Copyright 2014 La Trobe University, all rights reserved. Please contact for permissions.