If so, then all our present thoughts are mere accidents—the accidental by-product of the movement of atoms. And this holds for the thoughts of the materialists and astronomers as well as for anyone else’s. But if their thoughts—i.e., of Materialism and Astronomy—are merely accidental by-products, why should we believe them to be true? I see no reason for believing that one accident should be able to give me a correct account of all the other accidents.