A New Metaphysics of Necessity
There is a tacit recognition in the history of philosophy that in order to account for necessity we need to introduce a split in what we regard as overall reality. Thus, we have the idea that necessity resides in meaning, conceived as separate from the ordinary reality of things and properties, and also the idea that necessity resides in a totality of possible worlds, conceived as separate from the actual world. We need to adopt a type of dualism (doubling of worlds): of world and meaning, or of actual world and possible worlds. The latter worlds are conceived as shadowy (if not shady) in relation to the primary reality of the non-semantic and actual worlds. Necessity belongs in a separate sphere of reality, specially designed for it. These are both good ideas, in their way, because they accept that reality needs to be carved into two parts in order to do justice to necessity. A metaphysics of necessity needs to be ontologically expansive (non-local) in some way. Necessity can’t exist in a world consisting only of ordinary objects with ordinary properties (what we might call the-cat-sat-on-the-mat metaphysics). We might even have to countenance something relatively exotic. Along these lines, I will defend a split-reality metaphysics of necessity, specifically a two-worlds approach. I shall say that necessity is truth in the deep world and contingency is truth in the surface world. So, I believe in two worlds existing side by side, one deeper than the other. I am a “world dualist”. But my dualism is not the same as other dualisms that dot the philosophical landscape: mind and matter, appearance and reality, concrete and abstract, fact and value, particular and universal, noumenal and phenomenal. I have in mind a different sort of distinction that has no accepted name (or even being), which I will call the world of essences and the world of facts. The intuitive idea is that some truths correspond to things that have been brought together, assembled, combined, while other truths do not correspond to such joining, but concern inseparables, indivisible wholes. For example, my table may have a cup on it, which has been brought to the table from elsewhere and can be disjoined from it; it may also have the property of being brown or shiny. Such circumstances may be described as combinatorial in somewhat the manner in which Wittgenstein spoke of facts as combinations of objects (with properties and relations included under “objects”). These arrangements are contingent, accidental, mutable, conceivably otherwise. But my table might have other properties which are not like this, e.g., being made of wood (or a particular piece of wood). Here we cannot separate the object from the property: the wood was never brought to the table, combined with it, placed next to or on it. The wooden table is not the result of a combination of objects with a prior and independent existence: the table has no being without the wood that composes it. The truth that the table is made of wood (this wood) is a truth of essence not a truth of fact in the aforementioned sense; it isn’t combinatorial. It is a truth about the nature of the thing not about what accidentally befalls it. And natures are not combinations of independent existences, since without a nature a thing cannot exist at all. So, we have two levels or layers of being: a world of essences and a world of combinations (facts in roughly the sense Wittgenstein had in mind). The former give rise to necessities and are eternal and immutable; the latter give rise to contingencies and are (typically) temporary and mutable. We can say that necessities exist in the former world and contingencies exist in the latter world. These are different kinds of world (compare the world of meaning and the non-linguistic world) in that they have a different kind of “architecture”—one being combinatorial and the other being non-combinatorial. If the world is the totality of facts in Wittgenstein’s sense (complexes of objects), then that world does not include necessities (essences); and the world of essences does not include the world of facts, since it doesn’t admit of combination and recombination. (Note that Wittgenstein does not locate necessity in the world of facts, since for him it consists solely in tautologies). We have two different modes of being here—two different ways of constructing reality. And the point generalizes: numbers have no existence without their essential properties (there is no such thing as bringing evenness to the number 2), and bachelors are not combined with the state of being unmarried (they are unmarried by definition). In other words, de re necessities (and de dicto) are differently formed from contingencies—they are found not made, constitutive not compositional. You can’t arrange for the table (thattable) to be made of wood; it just is, essentially, ineluctably. The point is that talk of two worlds is justified by the inner architecture of the realities in question (I won’t say facts because I am using “fact” here in the narrow Wittgensteinian sense). But why do I say “deep world” and “surface world”? First, because we don’t see the world of essences; it is hidden from view. We know it but we don’t perceive it: we never observe the coming to be of an essential nature on the part of a pre-existing object, since there was no table before the piece of wood came into its life. But we do see the combining operation that forms contingent facts (we see the table being painted, for example). Second, the surface world presupposes the deep world in that there could be no combination of objects without antecedent objects possessing a determinate nature: essence precedes existence. Facts need constituents and constituents need natures. But the world of essences doesn’t need the world of facts (compare Plato on particulars and universals): things can have natures in logical independence of combining with other things. Third, the essence of an object is a deep truth about it in contrast to its contingent and fleeting properties. So, the world of essences is a deeper world than the world of facts; and this means that necessities are deeper than contingencies—more fundamental, more formative. Necessary truths are therefore metaphysically deeper than contingent truths. They call for a further world and this world is deeper than the world of contingency. We don’t need meanings and a plurality of worlds to capture the nature of necessity (in my judgment anyway) but we do need an extra layer of reality; we need that ontological split. Metaphysically speaking, necessity has to reside in a different place from contingency; it needs its own dimension. No doubt this is why it has always seemed metaphysically threatening (it was the biggest threat to logical positivism). Linguistic theories seek to confine it to the realm of meaning, while possible worlds theories multiply non-actual worlds for it to inhabit; according to the deep world theory, we need to recognize two layers to our world, with necessity existing in the deeper layer. Necessary truth is defined as truth in virtue of the deep world. Let me add that this theory, like the others, brings with it a vision of reality that can alter your way of seeing the world: you see it as having an outward perceptible form consisting of myriad combinations of objects and you see it as harboring an underlying reality of unchanging essences that are not combinatorial at all. There is no juxtaposing at this deeper level, no moving of pre-existing pieces around (like a chess game); rather, there are fixed and immutable indivisible realities—as that the table is essentially made of wood. In particular, the table and its constitutive chunk of wood were never at distinct points of space from which they moved in order to live happily together; rather, the table has no reality other than being made of that piece of wood. When you look at the table you are gazing at the intersection of two worlds, a world of essence and a world of accident (e.g., the cup sitting on the table for a while). Both these worlds occupy your visual field. You see the table as a metaphysical nexus consisting of a surface structure and a deep structure (to coin a phrase). The (whole) world is the totality of facts and essences. This is what you feast your eyes on every day. The universe comes to seem like a happy superimposition of one world on another, with necessity lurking just beneath the surface.
There is no inconsistency between the deep world theory and the other two theories, though I would object to them on other grounds. My point is that we all agree that necessity requires more than the ordinary world of perceived particulars; it needs its own special place—the question is where. An advantage of my proposal is that the necessity lies exactly where it is supposed to lie, i.e., in the object of predication, not in language or other worlds. It exists in the world of essences that underlies the world of facts, which is not somewhere else entirely.
 There is a question what to say about the necessity of origin, given that parents are spatially separate from their offspring. Here we should say that the child doesn’t have the property of being the child of these particular parents in an external manner, because without having that property it would not be the individual that it is. The case is like natural kinds: I don’t combine with the property of being human as I combine with the property of being a philosopher, because there is no conceiving of me as existing without being human. You can’t be said to combine with something that is a necessary condition of your existence. Combination requires logical independence.