  Now, it would be overstating matters to say that this problem appears only from a contemporary perspective; there was some recognition of it in the ancient and medieval  periods.[3] Still, before the advent of the experimental science, the problem was not strongly felt because experience was understood in a different way. For one thing, the notion of an experiment—an artificially constructed, single event or series of events designed to test for a predicted outcome—did not exist. Moreover, among the scholastic Aristotelians, a single, naturally occurring event could not by itself be regarded as revealing of natural processes, because it might be a “monster”—it might be an event that went against nature rather than being produced by and thus revealing of  nature.[4] Events as generally experienced, however, were regarded as being revealing of nature, and so they could provide the universal truths needed as premises in the  syllogism.[5] How was the gap between events as usually experienced—which still amounts to a limited sample of evidence—and the universal claim derived from them bridged? It is only from the modern and contemporary perspectives that such a gap exists to be bridged. For Aristotle and the medievals, human faculties are so constituted as to be able to apprehend nature, that is, to discern the essences of  substances.[6] In short, then, because the internal essences that form the content of natural philosophy are real, and because our faculties are so constituted as to apprehend those real essences, natural philosophy can be a science, a domain in which certain, demonstrative knowledge can be had, despite its dependence upon experience.