Scottish philosopher J. J. C. Smart says that `` sometimes a person who is really an atheist may describe herself , even passionately , as an agnostic because of unreasonable generalised philosophical skepticism which would preclude us from saying that we know anything whatever , except perhaps the truths of mathematics and formal logic . '' Scottish philosopher J. J. C. Smart even argues that `` sometimes a person who is really an atheist may describe herself , even passionately , as an agnostic because of unreasonable generalised philosophical skepticism which would preclude us from saying that we know anything whatever , except perhaps the truths of mathematics and formal logic . ''