Nature is enough on its own. Taking time, space, and matter in turn, then the ways they bind, the cosmic cycle, history, and life, the chapter makes that single case. What stays settled is the broad shape of things; what stays open (the exact constants, mechanisms, and particular history) is left to the sciences to fill in.

What the chapter has established, taken together, is the case its title names: Nature suffices for the structural and empirical work the chapter addresses. No external supplement is required by physics to initiate motion, source extension, or deposit substance. Some proposed supplements are structurally precluded where they remove the conditions required for the role they claim to perform; others are empirically and explanatorily idle because Nature already supplies the relevant work. A transcendent or essence-prior posit that declines to make a determinate empirical or grounding claim is not dissolved by this chapter alone; it remains a further metaphysical proposal whose credentials Chapters 5–6 assess.

*Sufficiency is not completeness.* To say that Nature is sufficient is not to say that Nature has been fully explained, or that the sciences have no open questions. It is to say that the remaining explanations are sought within Nature rather than supplied by an external structural source. Unknown mechanisms, unsettled interpretations, missing observations, and incomplete theories remain genuine unknowns. Nature Alone relocates those questions; it does not answer them by declaration.

The argument runs through three structural commitments and several empirical engagements. The three structural commitments are the book's claims about Temporality ([§7.2](<7.2 Time.md>)), Spatiality ([§7.3](<7.3 Space.md>)), and Physicality ([§7.4](<7.4 Substance.md>)): the roles are presented as jointly necessary within the book's modal framework. The chapter then compares those roles with familiar disputes in philosophy and physics, including the A/B debate, substantivalism and relationalism, and competing matter/energy ontologies. These comparisons are interpretive rather than deductions from physics. [§7.5](<7.5 Binding of the Conditions.md>) surveys spacetime, field structure, conservation, and symmetry as important physical frameworks whose empirical details remain theory dependent. [§7.6](<7.6 Singularity.md>) distinguishes the book's philosophical treatment of a stable zero-extension terminus from contested candidate cosmologies. [§7.7](<7.7 Cosmic History.md>) uses type/token language to organize the distinction between structural claims and contingent history without treating quantum foundations or cyclic recurrence as settled. [§7.8](<7.8 Life.md>) develops closure-plus-throughput as a philosophical model informed by, but not established by, thermodynamics, origins-of-life research, and evolutionary theory.

A through-line connects the chapter's engagements. The book proposes that several familiar oppositions can be read as tracking different aspects of a broader structural picture: tensed and tenseless descriptions, extension and relation, persistence and activity, lawful constraint and contingent history, and mechanism and organization. This is a proposed reframing, not a claim that the historical or scientific disputes have been conclusively dissolved. Each comparison must retain the qualifications of its own literature and empirical domain.

What the chapter has foreclosed is also uniform across layers. A Prime Mover external to the temporal series is foreclosed because Temporality is constitutive and directionally tilted *as* a medium ([§7.2.5](<7.2.5 What is Concluded.md>)). An external source of extension is foreclosed because Spatiality is the relational fact Nature realizes ([§7.3.5](<7.3.5 What is Concluded.md>)). A creator-deposit at the first instant is foreclosed because Substance, the bearer of Physicality, is not subject to coming-from-nothing ([§7.4.5](<7.4.5 What is Concluded.md>)). A first-cause cosmological argument receives a philosophical reply here, but the chapter does not establish past-eternal cosmology or a specific bounce model ([§7.6.5](<7.6.5 What is Concluded.md>)). Fine-tuning claims about particular constants and initial conditions remain questions for physics and cosmology; the structural argument does not provide their empirical resolution ([§7.7.5](<7.7.5 What is Concluded.md>)). Likewise, closure-plus-throughput is offered as a model of life rather than a scientifically settled replacement for every form of vitalism, mechanism, or origins-of-life theory ([§7.8.5](<7.8.5 What is Concluded.md>)). These foreclosures are of two kinds — call them *constitutive preclusion* and *explanatory idleness* — and the difference matters. Where the role is constitutive, Temporality's tilt, Spatiality's relational fact, Substance's immunity to coming-from-nothing, life's identity with closure-plus-throughput, the supplementation is *precluded*: there is no coherent job left for it, because what it would supply is what the medium already *is*. Where it is merely unnecessary (the first cause that past-eternity removes the need for, the special providence the type/token composition already accounts for) it is not strictly precluded but *rendered explanatorily idle*: nothing rules out positing it, but it earns no explanatory keep. The chapter precludes the first kind and retires the second; only the first carries modal weight. Every foreclosure here is conditional on the Chapter 2 modal core: chiefly the impossibility of absolute nothingness ([§2.7](<2.7 Nothing to Consider.md>)) and the necessary co-instantiation of Temporality, Spatiality, and Physicality. A critic who rejects the inference from the inconceivability of absolute nothingness to its impossibility resists the chapter at that upstream point, not at any step taken here.

What remains open is also uniform. The chapter fixes the type at every layer; the specific tokens at each layer are empirical, contingent, and corrigible. The exact mechanism of the bounce, the specific geometry of Spatiality, the specific list of conserved quantities, the specific values of physical constants, the specific compatibilist reading of token-level agency, the specific site of the first closure, the specific chemistry of life elsewhere, the specific historical lineage that produced this observer reading this page, these are open for physics, cosmology, philosophy of mind, and astrobiology to settle, and the structural argument deliberately does not pre-empt them. What the structural argument supplies is the frame within which their settlement is even possible.

A word about what the chapter has not done. It has not given an inside account of what it is like to be the kind of configuration [§7.8](<7.8 Life.md>) identifies, once the configuration is deep enough to model itself. The closure-plus-throughput criterion describes the configuration from without; what the configuration is from within, what subjective experience consists in, what the structure of consciousness is when read from inside the self-modeling recursion, is the chapter-end Chapter 7 → Chapter 8 lift the [§7.8](<7.8 Life.md>) cluster carries on the chapter's behalf. That first-person register operates on a structured space (the *modal field*) which is the body's accumulated representation of what is possible, weighted by its own stakes in each branch (see [§8.3](<8.3 Knowledge.md>) for the full account; the Modal Convergence Theorem establishes its mutual-holding structure across currents). The modal field is what the recursion from Chapter 8 onward is working on; it enters the book here, at the threshold, because it is what the inside of the closure-plus-throughput model of [§7.8](<7.8 Life.md>) consists in once the recursion is deep enough to have one. Chapter 8 takes that work up, treating consciousness and its downstream registers once the structural ground established in this chapter is in place.

This is also where a promise from the groundwork comes due. [§1.4.4](<1.4.4 Triconditional Structure.md>) names Nature but deliberately withholds its identity with *the universe* in the totality sense (the whole of what there is, as against this contingent arrangement of galaxies and matter) flagging that identity as a claim to be earned rather than stipulated. [§2.8.5](<2.8.5 Necessity of Nature.md>) earns the modal half: necessarily, Reality is Nature (T6, the Necessity of Nature). Chapter 7 supplies the rest. If Nature suffices (if nothing stands outside it to initiate, ground, supplement, or precede it) then the totality of what there is contains nothing that is not Nature, and *the universe* in the only sense that survives the [§1.4.4](<1.4.4 Triconditional Structure.md>) split is neither a rival to Nature nor a container for it. The three names converge: the whole anything real belongs to (*Reality*, [§1.1](<1.1 Reality.md>)), the joint necessity of Temporality, Spatiality, and Physicality (*Nature*, [§1.4.4](<1.4.4 Triconditional Structure.md>)), and the totality of what there is (*the universe*, totality sense) all pick out the same structure. What was flagged at [§1.4.4](<1.4.4 Triconditional Structure.md>) and earned modally at [§2.8.5](<2.8.5 Necessity of Nature.md>) is, with *Nature Alone* in place, discharged without remainder: the universe, Reality, and Nature are one and the same.

> [!corollary]
> **The Identity of the Totality** · **R20** · *Result of T6*
>
> Necessarily, Reality is Nature: the modal half is immediate from T6 ([§2.8.5](<2.8.5 Necessity of Nature.md>)), which gives □(R = N). With Nature Alone in place (this chapter), nothing stands outside Nature to ground or supplement it, so the totality of what there is just is Nature, and the universe in the only sense that survives the [§1.4.4](<1.4.4 Triconditional Structure.md>) split is Nature itself. Reality ([§1.1](<1.1 Reality.md>)), Nature ([§1.4.4](<1.4.4 Triconditional Structure.md>)), and the universe in the totality sense are therefore one structure under three names, not three things that happen to coincide. The contingent-arrangement sense of "universe" (this configuration of galaxies and matter) is expressly excluded ([§1.4.4](<1.4.4 Triconditional Structure.md>)).

The identity has a third edge, beyond the two just drawn. To say Reality is Nature identifies the inclusive structural totality within the book's modal framework: no second **structural** Nature or container around the global domain is needed. This establishes inclusive structural unicity. It does not, by this chapter alone, settle every metaphysical proposal of transcendence that refuses to function as a determinate ground, world, or empirical supplement. Nor does it fix the census of concrete worlds — how many concrete configurations the one structural totality contains. But the open census should not be mistaken for an open unicity, and here the identity delivers more than a deferral. Reality is what anything real belongs to ([§1.1](<1.1 Reality.md>)), and by the Necessity of Nature whatever is real instantiates Temporality, Spatiality, and Physicality rather than some second structure ([§2.8.5](<2.8.5 Necessity of Nature.md>)). So if there are many concrete worlds, they are many configurations *within* the one Nature — internal population, not rival totalities. The plurality question is thereby domesticated rather than left standing: whatever its answer, it is a question about the internal census of the one structural totality, never a question about how many Natures there are. The one view built to resist the domestication is the modal realist's plurality of wholly isolated concrete worlds, taken up at [§4.4.1](<4.4.1 Modal Realism.md>); to escape the present result it must decline the [§1.1](<1.1 Reality.md>) totality conception itself, which relocates the disagreement to the same upstream point at which the chapter has already placed its other principled resister. Even there the resistance is not free: the count the plurality keeps for itself is the count [§4.4.1](<4.4.1 Modal Realism.md>) finds never closing on the theory’s own machinery, so declining the one Nature purchases not a rival answer to the census question but a census that never becomes a number. Unicity is not an extra posit laid over the identity but the identity taken at its full width: the totality is singular in admitting no outside or second Nature.

Nature is not a system on which order has been imposed from outside; it is the configuration order takes. The chapter has read that configuration at the level on which the structural argument operates and shown that no other reading is required.


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← [7.8.5 What is Concluded](<7.8.5 What is Concluded.md>) | [8. Expanding the Field](<8. Expanding the Field.md>) →
