  Common sense principles possess “the consent of ages and nations, of the learned and unlearned, [which] ought to have great authority with regard to first principles, where every man is a competent judge” (EIP 6.4, 464).  Common sense principles are common sense because, but not only because, they are common to humanity. Reid's account of common sense does not itself approach the status of a philosophical or psychological theory. Though his commitment to common sense forms a key component in his philosophical method, a deeper methodological principle clearly underlies his appeal to common sense. Reid attempts to build his fallibilist, foundationalist account of empirical knowledge while working under an empiricist constraint that prohibits speculative use of a priori reason. As a result, Reid's reference to beliefs held in common across time and place, across culture and religion, functions as an empirically justified generalization about species-typical features of human cognition.