Nature (the joint structure of T, S, and Φ) is necessary not merely as a modal conclusion but as the precondition for any possible state of affairs. The thesis is the *Necessity of Nature*: the modal-structure claim that the structural Conditions are necessarily jointly instantiated, and that this jointly instantiated structure is what we mean by Nature.

The position is sometimes mistaken for physicalism. It is not. Physicalism, in slogan form, is the thesis that everything is physical; in its strongest contemporary form it is a thesis about fundamentality: the physical (matter-energy, the domain Φ picks out) is fundamental, and everything else is grounded in or nothing over and above it (*fundamentality physicalism*). It is this basement claim the triconditional refuses. Φ is one of three co-equal structural roles, not the floor on which the others rest. The point can be stated formally:

> [!argument]
> **Why the View Is Not Fundamentality Physicalism** · *No One-Way Φ Basement.* Let N abbreviate *Nature obtains*; T, S, Φ as before.
>
> 1. *Triconditional Identity (T5).* Nature is the joint structural complex: N ↔ T∧S∧Φ. ([§2.6.10](<2.6.10 Triconditional Identity.md>))
>
> 1. *Triconditional Cross-Entailment (T3).* Within full change-realizing structure, Φ requires T and S, and each Condition likewise requires the other two. ([§2.6.7](<2.6.7 Triconditional Cross-Entailment.md>))
>
> 1. The dependence asserted here is symmetric and co-constitutive, not a one-way grounding relation from Φ to T and S.
>
> 1. Fundamentality physicalism, in the basement form targeted here, requires an asymmetric priority claim: Φ grounds T and S while not being co-grounded or co-constituted by them.
>
> 1. That priority claim is incompatible with T3's co-constitutive structure. Therefore the present view is not fundamentality physicalism and cannot privilege Φ as the sole basement.
>
> 1. This does not by itself refute every thesis called *physicalism*; it rejects the specific one-way fundamentality thesis once the Triconditional Cross-Entailment is granted.

The bare thesis that every entity is physical is left standing by this block, and deliberately so: T and S are not entities but dimensional Conditions, so they were never candidate counterexamples to a claim about what things exist. But that survival costs the physicalist the basement. A physicalism that grants T and S as non-physical structure presupposed by the physical has already conceded fundamentality; what it arrives at is the naturalism defended here: Nature as T∧S∧Φ, with no privileged floor. The only way to keep the physical fundamental is to deny the distinctness the block presupposes, claiming that T and S are themselves Φ; that denial is met at [§2.6.4](<2.6.4 Persistence's Two Conditions.md>) and the Ontological Identity ([§2.6.8](<2.6.8 Ontological Identity.md>)).

This places the view on the monist side of an old divide, but not where readers often assume. Denying that Φ is the floor does not multiply substances: there is one structured reality, T∧S∧Φ, not two kinds of stuff, so the position is a monism, not a dualism. What it is *not* is a substance monism in the fundamentality sense: the thesis that one category, substance, is the single basement from which all else derives. That thesis privileges Φ exactly as physicalism does, and the block above refuses it on the same ground. The monism defended here is triconditional: one reality under three co-equal structural readings, none of them the floor. A reader who arrives holding "I am a monist, not a dualist" is already inside the position; the book asks only that the monism not be cashed as the priority of any one Condition.

The position is friendlier to the working physicist than physicalism is. A physicist describes structure: how matter persists, how distance is measured, how succession orders events. Physicalism commits the physicist to a metaphysical claim (that matter is foundational) that no actual physics asserts. The *Necessity of Nature* asks only what physics is already constrained to describe: the necessary structural Conditions under which anything is a being at all. A future physics that revised every current posit would still describe something that persists across distance through time, or it would not be physics. The thesis is neither empirically hostage nor contentless: its content is modal-structural rather than empirical.

An objection presses hardest in this form: a candidate ground might be specified as standing in no spatial or temporal relation to what it grounds, operating at the level at which space and time themselves are sustained. Granted in its strongest form, the position holds that this is a mode of causal power that does not fit the standard template, not the absence of causal power. Even there, the constitutive identity of [§2.6.4](<2.6.4 Persistence's Two Conditions.md>) returns the same answer. Causal power just *is* the instantiation of Physicality's constitutive structure: the capacity to affect and be affected, the distinctness of initiating and receiving relata, the persistence of the connection between cause and effect. A being with causal power instantiates Physicality, regardless of what substrate it occupies. A being that genuinely lacks any instantiation of Physicality's structure is not a being with causal power in some alternative mode. It is a being with no causal power at all: ∅, not a candidate ground that escapes the requirement. The classical-theist reply that *causal power* may apply to such a ground only analogically (not univocally with the causal power of finite beings) inherits the diagnostic of [§2.7.1](<2.7.1 Null State (∅).md>). Any analogical predication of causal power that retains the source-to-recipient articulation imports T (succession), S (distinction), and Φ (persistence) under that articulation; any analogical predication that strips the articulation altogether names ∅. The fuller analogical-versus-univocal predication question is engaged at [§5.2.1](<5.2.1 Divine Simplicity.md>) (the analogia entis treatment) and [§5.2.2](<5.2.2 Via Negativa.md>) (the analogical-apophatic complementarity).

A further consequence sharpens the point. Any existence claim must cash out in obtaining: in something's being the case. But to obtain is to take place: to be situated temporally (it obtains now rather than never), spatially (here rather than nowhere), and causally (as a result of structural Conditions rather than as a free-floating label). Taking place is not a metaphor. It is the literal minimum content of obtaining.

A being defined as placeless, timeless, and immaterial does not merely fail to act within the structure. It fails to obtain as a state at all. To exist *is* to take place. There is nothing outside of reality, because it could not be real. You are taking place right now.

A putative purely abstract entity that is not proposed as a ground of anything and hosts no causal relations is a different case, addressed in [§4.2.4](<4.2.4 Platonism.md>); the claim here targets any entity proposed as the ground of existence, which must itself obtain in order to ground.

The *Necessity of Nature* is not a philosophical position one chooses. It is the modal-structure requirement for choosing. The load-bearing argument is the formal block above; the literary closing that follows is a positioning move, not part of the derivation. Plantinga's modal argument deploys S5 to establish the necessity of a being: the title of that work is *The Nature of Necessity*. The present argument deploys the same machinery to establish the necessity of Nature. The inversion is a tool-and-target reuse rather than a rhetorical flourish: Plantinga's S5 deployment is valid; the inverted reading is that what S5 establishes the necessity of, when carefully attended to, is the necessary structural ground itself rather than a being separately necessary from it. Plantinga found the tool; the conclusion it yields is Nature.[^2-8-3-not-physicalism-ch4]

[^2-8-3-not-physicalism-ch4]: The Necessity of Nature as a thesis (the modal-structure claim that Nature is the necessary structure of T∧S∧Φ) is engaged in Chapter 4. Idealism is the inverse position, locating the basement in mind rather than in any of the three Conditions ([§4.3.5](<4.3.5 Idealism.md>)); Russellian monism posits intrinsic categorical natures behind the structure ([§4.3.3](<4.3.3 Russellian Monism.md>)); Plantinga's modal ontological argument is the tool whose target the present argument inverts ([§5.1.7](<5.1.7 Modal Ontological Argument.md>)); and classical simplicity, with the analogia entis reply that causal power applies to a placeless ground only analogically, is the most demanding case, where a candidate ground is held to lack T, S, and Φ ([§5.2.1](<5.2.1 Divine Simplicity.md>)).


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← [2.8.2 Nature Cannot Be Denied](<2.8.2 Nature Cannot Be Denied.md>) | [2.8.4 Necessity Precedes Contingency](<2.8.4 Necessity Precedes Contingency.md>) →
