" Imagine a world in which people told lies as a matter of principle, where lying was regarded as a good and moral thing to do. In such a world, lying itself would cease to have any meaning. Lying needs a presumption of truth for its very definition. If a moral principle is something we should wish everybody to follow, lying cannot be a moral principle because the principle itself would break down in meaninglessness. Lying, as a rule for life, is inherently unstable. More generally, selfishness, or free-riding parasitism on the goodwill of others, may work for me as a lone selfish individual and give me personal satisfaction. But I cannot wish that everybody would adopt selfish parasitism as a moral principle, if only because then I would have nobody to parasitize. "

― Richard Dawkins , The God Delusion