The things which are temporal arise by their participation in the things which are eternal. The two sets are mediated by a thing which combines the actuality of what is temporal with the timelessness of what is potential. This final entity is the divine element in the world, by which the barren inefficient disjunction of abstract potentialities obtains primordially the efficient conjunction of ideal realization. This ideal realization of potentialities in a primordial actual entity constitutes the metaphysical stability whereby the actual process exemplifies general principles of metaphysics, and attains the ends proper to specific types of emergent order. By reason of the actuality of this primordial valuation of pure potentials, each eternal object has a definite, effective relevance to each concrescent process. Apart from such orderings, there would be a complete disjunction of eternal objects unrealized in the temporal world. Novelty would be meaningless, and inconceivable. We are here extending and rigidly applying Hume's principle, that ideas of reflection are derived from actual facts.
By this recognition of the divine element the general Aristotelian principle is maintained that, apart from things that are actual, there is nothing--nothing either in fact or in efficacy. This is the true general principle which underlies Descartes' dictum: "For this reason, when we perceive any attribute, we therefore conclude that some existing thing or substance to which it may be attributed, is necessarily present." ... everything is positively somewhere in actuality, and in potency everywhere.
Alfred North Whitehead, Process and Reality