II. It is not that which explains itself but that which perplexes us that moves to enquiry. Metaphysic would never have come into being if the course of events, in that form in which it was presented by immediate perception, had not conflicted with expectations, the fulfilment of which men deemed themselves entitled to demand from whatever was to be reckoned as truly existing or truly taking place. These expectations might be accounted for in various ways. They might be held to be innate to the intelligent spirit. If that were true of them, it would follow that, in the form of necessary assumptions as to the mode of existence and connexion of anything that can possibly be or happen, they determine our judgment upon every occurrence with which observation presents us. Or they might be taken to consist in requirements arising in the heart out of its needs.