§ 3. The _Monadism_ of Leibnitz was an attempt to effect a compromise between Pluralism and Monism. According to this view, the universe consists of an infinite plurality of fundamentally separate beings. These beings are at once simple and indivisible, and at the same time each of them contains an infinite variety of internal states. Being mutually independent, the monads have no genuine relations with each other; each is conscious only of the succession of its own states. As Leibnitz expressed it in a metaphor which has become classic, the monad has no windows. So far the system is pure Pluralism. But at the same time the unity of the whole system of monads, though “ideal” and not “real,” is to be genuine. They form a system “ideally,”—_i.e._ for the understanding of an omniscient spectator,—inasmuch as the internal states of each monad are adjusted to those of all the rest, or, as Leibnitz also puts it, inasmuch as each monad “represents” the same systematic structure from its own special point of view. Hence, though no monad really perceives or acts upon any other, every monad behaves as it would _if_ there were mutual perception and interaction between all. When we ask after the source of this “pre-established harmony,” we meet with a double answer. On the one hand, its actual _existence_ as a fact is due to the creative will of God. On the other, it was precisely the complete adjustment of the internal states of its various monads which determined God to will the existence of the actual world-order in preference to that of any other of the indefinitely numerous logically possible arrangements which He foresaw and might have chosen. This relation between God and the world-order is further complicated by the fact that on occasion Leibnitz treats God as simply one, though the supreme one, among the monads.