constitution a relation between concrete particulars (including objects and events) and their parts, according to which at some time t, a concrete particular is said to be constituted by the sum of its parts without necessarily being identical with that sum. For instance, at some specific time t, Mt. Everest is constituted by the various chunks of rock and other matter that form Everest at t, though at t Everest would still have been Everest even if, contrary to fact, some particular rock that is part of the sum had been absent. Hence, although Mt. Everest is not identical to the sum of its material parts at t, it is constituted by them. The relation of constitution figures importantly in recent attempts to articulate and defend metaphysical physicalism (naturalism). To capture the idea that all that exists is ultimately physical, we may say that at the lowest level of reality, there are only microphysical phenomena, governed by the laws of microphysics, and that all other objects and events are ultimately constituted by objects and events at the microphysical level. See also IDENTITY, MORAL REALISM , NATURALISM , PHYSICALISM , REDUCTIO. M.C.T.