Glasgow's notion that religious belief is a psychological delusion to be explained by the mechanism of projection is, of course, common to Nietzsche, Schopenhauer, and Schopenhauer's sources in French materialism, including Helvetius and his friend Holbach: for thirty years Helvetius dined at Holbach's twice a week, while Holbach was writing works including The System of Nature: "theologians were, and always will be true anthropomorphites.