Quine denies that the modal vocabulary is intelligible. Van Inwagen grants it and denies something else: that the faculty by which we reach modal verdicts is reliable at the distances philosophy asks it to work at. (van Inwagen, Peter, 1998) is the canonical statement. Ordinary modal knowledge is secure, on this view, because it operates by small variation on the actual: the table could have stood two feet to the left, the meeting could have run long. Remote modal claims (that there could be a being than which none greater can be conceived, that there could be a physical duplicate of a person lacking consciousness, that transparent iron is possible) are cases where the faculty has been carried far past anything that calibrates it, and the confident verdicts philosophers return are not knowledge.

This is not the skepticism of [§4.1.6](<4.1.6 Quinean Modal Skepticism.md>), and the two must not be run together. The Quinean refuses the vocabulary. Van Inwagen keeps the vocabulary, keeps ordinary modal knowledge, and refuses the extension. A reply that vindicates the intelligibility of *necessarily* leaves his objection entirely untouched, which is why it needs its own address. Its compositional half is discharged at [§4.3.11](<4.3.11 Mereological Nihilism.md>); the half taken up here is the one that section explicitly defers.

The objection lands with more force here than almost anywhere, because □(T∧S∧Φ) is about as remote as a modal claim gets. It quantifies over every world, including worlds bearing no resemblance to anything experienced, and it returns a verdict of necessity rather than mere pervasiveness. By van Inwagen's own criterion of similarity to ordinary life, no claim in the book is further from the calibrated range.

The concession runs in full, and it is larger than the concessions elsewhere in [§4.1](<4.1 Modal and Semantic Foundations.md>). Van Inwagen is right that a great deal of analytic metaphysics has run on brute intuitions about distant scenarios; right that no one has produced a credible account of a faculty that would deliver such verdicts reliably; right that the modal ontological argument and the zombie argument both turn on exactly this move; right that the burden falls on whoever wants a remote modal conclusion. [§3.3.4](<3. Convergence.md>) already agrees, and the agreement there is not tactical. The book's own treatment of conceivability is closer to van Inwagen's than to his opponents'.

*First.* The remoteness form runs directly. Ordinary modal knowledge proceeds by imaginative variation from the actual, the reach of that method is short, and □(T∧S∧Φ) lies far outside it. So whatever warrant the conclusion has, it cannot be the warrant ordinary modal claims have.

The reply is that the conclusion is not an output of that method, and the point is methodological rather than defensive. The argument nowhere asks the reader to imagine a world and report what is found there. It asks the reader to *specify* one and observe what the specification requires. Those are different operations, and only the second is publicly checkable. [§2.1.5](<2.1.5 The S5 Bottleneck.md>) is the clearest case: it does not invite the objector to picture a world lacking the structural conditions, it invites the objector to describe one, and the argument turns on what the description turns out to contain. An invitation to describe can be accepted or declined in a way an invitation to imagine cannot, and its results can be inspected by someone who does not share the imaginer's phenomenology. Van Inwagen's skepticism is calibrated against a faculty; the derivation does not run on that faculty.

The inversion is worth stating plainly, because it is the book's general shape. Where the standard method treats *I can conceive of it* as evidence for possibility, the method here treats *the attempt to specify it consumes what it denies* as evidence for impossibility. The first is a report about the person; the second is a result about the attempt.

*Second.* The parity form presses that the reply has not escaped anything. The premises of the derivation are themselves modal claims (that a way must have direction, difference, and bearer; that no world can lack the conditions), and modal claims are what the skepticism targets. Relocating the warrant from imagination to specification changes the vocabulary of the defense without changing what is being defended.

The reply distinguishes two ways a modal verdict can be reached. One surveys possibilities and reports what is found among them, and that method requires epistemic access to the possibilities surveyed, which at remote distances is exactly what van Inwagen denies is available. The other attempts to construct a specification and finds that the construction cannot be completed, and that method requires no access to anything remote. The attempt is made here, with materials available here, and its failure is observed here. That *no way* and *impossible* are two names for one verdict is the surface expression of the point: a no-way result is reached by trying and failing, not by looking and not finding. The premises the parity objection targets are of the second kind. They are not reports about distant worlds but results about what a description must contain in order to be a description of anything at all, and their test is performable at zero distance.

*Third.* The reliability form is the strongest, and it comes from both directions. (Roca-Royes, Sonia, 2011) presses that conceivability-based methods do not deliver *de re* modal knowledge of the kind essentialist conclusions require. From the other side (Hawke, Peter, 2011) argues that van Inwagen's own similarity-to-ordinary-life criterion is unstable, either permitting too much or forbidding the ordinary knowledge it means to protect. Pressed at the present argument, the form asks why an inability to complete a specification should indicate impossibility rather than a limit on the specifier. Every argument from failure-to-construct risks being an argument from ignorance.

The worry is granted in general and answered in the particular. Inability to specify is defeasible evidence, never proof, and an argument that rested on bare inability would be worthless. What distinguishes the cases the book relies on is that the failure is *diagnosed* rather than merely encountered. When the objector attempts to specify a world lacking the structural conditions, the attempt does not simply stall; it proceeds by individuating that world from others, locating it as a state that obtains, and contrasting it with the worlds it differs from, which is to deploy distinction, succession, and bearing in the act of denying them. That is a demonstrated self-defeat with a stated mechanism, not an absence of imagination. The distinction between *I cannot think how* and *the attempt consumes what it denies* is the whole of the reply, and only the second carries weight.

> [!premise]
> **The Specification Test** · *Standard*
>
> 1. For a remote candidate p, the question is not whether ◇p is imaginable but whether p can be specified.
>
> 1. A specification is adequate only if it does not deploy what p denies.
>
> 1. Where every attempted specification deploys what p denies, and the deployment can be exhibited, the failure is diagnosed rather than merely encountered.
>
> 1. A diagnosed failure is evidence of impossibility. An undiagnosed failure is evidence only about the specifier.
>
> 1. Negative results are claimed here only where (3) holds, and are to be marked as conjectural where it does not.

The standard cuts against the book as well as for it, which is the reason to adopt it. It commits the argument to marking which of its negative results are diagnosed and which rest on nothing better than an unproductive search, and any result of the second kind is owed a downgrade rather than a defense.

That marking has been carried out rather than promised. Across the load-bearing negative results of Chapters 2 and 3 — the Negation Seal at [§2.1.5](<2.1.5 The S5 Bottleneck.md>), the null-state reductio and the subtraction reply at [§3.2.6](<3. Convergence.md>), the fictionalist escape at [§3.3.3](<3. Convergence.md>), the masking test at [§2.4.12](<2.4.12 The Masking Test.md>), the conceivability trap at [§3.3.4](<3. Convergence.md>) — and across every verdict in the Chapter 4 ledger, the results the argument relies on are diagnosed in the sense clause 3 requires. One exception was found and corrected. A verdict on strict temporal unreality had been recorded as an incoherence result when the section supporting it claims only an act-side burden and leaves the object-side error theory open ([§4.2.5](<4.2.5 The Unreality of Time.md>)); it now states the weaker result. The exception is reported here rather than silently repaired, because a standard whose first application finds nothing is not being applied. The pattern behind it is worth naming as well: the failure was not an undiagnosed argument but a summary that claimed more than the section beneath it, which is where this standard is likely to be broken again.

An ally is available and should be recorded, though the argument does not depend on it. (Williamson, Timothy, 2007) [ch. 5] argues that modal knowledge is not the deliverance of a special faculty at all but a byproduct of the ordinary capacity to evaluate counterfactuals, which is exercised constantly and is not obviously less reliable at metaphysical distances than at everyday ones. If that account is right, van Inwagen's skepticism loses its target, because there is no distinct modal faculty whose calibration range can be exceeded. The present reply is deliberately weaker and does not require Williamson's account to be correct. It requires only that specification is a different operation from imagination, and that its failures can be diagnosed.

*What closes.* Van Inwagen's challenge is not answered by showing that modal vocabulary is meaningful, which is why [§4.1.6](<4.1.6 Quinean Modal Skepticism.md>) does not answer it, and it is not answered by producing a confident intuition at the relevant distance, which is what the challenge forbids. It is answered by declining the method the challenge is calibrated against. The conclusion is reached by attempted specification and diagnosed failure rather than by imaginative survey, and those failures are exhibited rather than reported. What remains of the objection is a standing demand, correctly placed: that the book distinguish the results whose failures it can diagnose from the results where it has not succeeded in finding a counterexample. The demand is accepted. Van Inwagen was right about the faculty, and right that most of what has been built on it should be given up; the argument here is built on something else.


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← [4.1.12 Dispositionalism about Modality](<4.1.12 Dispositionalism about Modality.md>) | [4.1.14 Impossible Worlds and Relative Modality](<4.1.14 Impossible Worlds and Relative Modality.md>) →
