You rightly emphasize that inquiry presupposes what stands fast, but you tend to treat these certainties as outside epistemic assessment altogether. How, then, do you account for intellectual conversion—those moments when what once stood fast becomes questionable and inquiry reorganizes itself at a deeper level? Are your hinges provisional horizons, or final grammatical boundaries? — Esse Quam Videri

Conversion is real, and it’s actually a good test of what I believe Wittgenstein means by hinges. Some hinges that stand fast for us are local and revisable (like the rules of chess), and when they shift the whole field of inquiry gets reorganized. But not everything that stands fast is like that. There are also deeper certainties (I'm an object separate from other objects) that function as conditions of intelligibility for doubt and checking in the first place, and those don’t shift in the same way, because if they did the activity of inquiry would collapse.

My answer is: hinges aren’t all on one level (some are foundational, but others are bedrock). Some are provisional horizons within a practice, the ones that can change as inquiry advances. Others are grammatical boundaries in the strict sense, the background without which “evidence,” “error,” “correction,” and “defeater” stop having any role. Intellectual conversion is usually a reorganization among the first kind, a shift in what was taken for granted within the system.

This is why I call (and others) hinge certainty arational. It’s not that a hinge is sacred or immune by decree. It’s that hinges typically aren’t the kind of things that are decided by the ordinary routes of objective justification. When they genuinely change, it’s less like refuting a claim and more like adopting a new framework.

Thank you for these clarifying remarks. I have one additional follow-up question: in your account, is objective justification sufficient for knowledge, or is it a necessary but fallible condition whose success still depends on the independent fulfillment of conditions?

You say, quite reasonably, that epistemology cannot guarantee orientation toward reality by introspection alone, and I agree entirely. But I would be similarly reluctant to say that orientation toward reality is guaranteed by practice instead.

The residual worry here is this: practices can be corrigible, sensitive to defeat, and historically successful, and yet still fail to deliver truth in particular cases. It seems that at some point we must appeal to ‘being’ (what-is-the-case) in order to explain how a judgement can fully satisfy the norms of well-governed practice and yet still fail to be true. Practice can regulate responsibility, but success still depends on how things are. I'm not saying that you are refusing to make such an appeal, only that I didn't see it stated explicitly anywhere in your paper. — Esse Quam Videri

Objective justification is necessary for knowledge, but it’s not a guarantee, because truth is the success condition. For example, I say in the paper “Truth remains the success condition for knowledge. To say that a belief is true is to say that the world is as the proposition represents it.”

However, even a well-governed practice is subject to failure: a belief can meet the standards and still turn out false. That’s not a defect in the idea of objective justification; it’s part the fallible character of our justificatory system.

What objective justification does secure is the right to claim "I know..." the right to treat the belief as knowledge, given our best efforts. That’s why I point to the guardrails: they don’t make truth automatic; they discipline the way justification can fail. “No False Grounds excludes cases in which the support is defective… Practice Safety excludes cases in which truth is reached only by luck… Defeater Screening excludes cases in which the belief cannot retain standing under relevant challenge.”

This is also why I keep insisting that the target is epistemic certainty, not absolute certainty: “much of what we count as knowledge is not secured by absolute certainty,” and JTB+U clarifies “how fallibility and knowledge coexist.”

If you want one line: objective justification governs responsibility and standing, truth governs success, and my claim is that we can have real knowledge without infallibility because our practice of justification aims at disciplined, defeater-resistant stability, while still understanding that “how things are” can definitely surprise us.

1. On Justification vs. Judgment
You speak eloquently about justification within practice, but where, precisely, is judgment?

You describe justification as a public standing governed by grammar and practice, but you do not clearly distinguish justification from the reflective act of judgment by which the subject affirms that the conditions for truth are fulfilled. Do you intend judgment to be absorbed into justification, or is it an irreducible moment you have not yet made explicit? If it is absorbed, how do you avoid collapsing epistemic success into conformity with practice?

Main concern: Knowledge is not exhausted by correct use or standing; it culminates in an act of judgment that affirms being. I would argue that act cannot be replaced by grammar without loss. — Esse Quam Videri

I don’t want “judgment” to disappear, and I’m not trying to replace it with grammar. I’m trying to locate its role in the process.

On my view, judgment is the act of taking p to be true, the moment a person makes a commitment about belief X. Objective justification is what makes that commitment responsible, not a mere statement. So judgment and justification aren’t rivals. Judgment is the affirmation of X, justification is the warrant for that affirmation in a practice that includes standards for evidence, mistake, correction, and defeat. Without judgment, you don’t have a claim at all. Without objective justification, you have conviction, guesswork, or mere assent, even if you can produce something that looks like a justification.

That also answers the worry about collapse into conformity. My account doesn’t say “whatever a practice treats as justified is thereby knowledge.” A practice can be defective, insulated, or sloppy. That’s exactly why I make the constraints explicit, viz, the practice has to be one where error is possible, correction is intelligible, defeaters are taken seriously, and standards are answerable to failure modes. If those conditions aren’t in place, then you can have judgment and even conformity, but you don’t have objective justification in my sense.

On your last line, “an act of judgment that affirms being,” I’d put it a bit differently. Judgment can be oriented toward what is the case, and in that sense, it aims at reality (the facts), but epistemology can’t guarantee that orientation by introspection alone. That’s why I keep the paper aimed at epistemic certainty, objective justification, not at Cartesian absolute certainty. Judgment is irreducible as a human act, but the epistemic status of the judgment depends on whether it is governed by the right standards of practice rather than merely produced with confidence.

As I'm going through your paper -- which is extremely good -- I want to clarify one thing: Do you consider that traditional JTB is supposed to guarantee knowledge? Or is its goal more modest -- to provide grounds for claiming knowledge? — J

I take traditional JTB to be doing something more modest than guaranteeing knowledge in any infallible sense. I treat it as a grammar for when a claim to know is responsibly made, a true belief with objective justification in the relevant practice of what justification entails within the 5 methods I describe. That’s why I say JTB “mirrors the way we distinguish between mere belief and belief that has a secure place in our shared life,” and why it remains “a natural starting point” for thinking about knowledge.

This is also where it helps to separate JTB as a definition from JTB in practice. As a definition, it gives a clean schema. In practice, justification is not a simple box-check, it’s what your claim can actually justify inside a practice that has standards for evidence, error, correction, and defeat, and that treats some challenges as relevant and some not.

Those standards of practice (justification) aren’t private feelings or inner impressions, they’re “displayed in our shared procedures of correction and agreement, in what counts as getting it right and what counts as needing revision.”

I don't claim that JTB guarantees knowledge unless you're speaking about deductive reasoning (it's absolute in a restricted way). Most of our knowledge is inductive and so it's mostly probabilistic. It really depends on your method of justification. The method I provide can do both.

So in my framework, I talk about four senses of certainty, and these help explain the two different uses of "I know." First, there's epistemic certainty, which is really about having objective justification, something that stands up to public criteria and can’t easily be defeated. Then there's subjective certainty, which is more about personal conviction, it's the feeling of being sure about something from your own perspective. There's absolute certainty, which is tied to logical or moral necessity, i.e., things that simply cannot be otherwise. And finally, there's hinge certainty, viz., those arational bedrock commitments that make all these other kinds of certainty possible.

Now, when we say, "I know," we can be using it in that subjective sense, expressing a personal conviction, or we can be using it in the epistemic sense, pointing to something that meets those public standards of justification. My approach tries to show how these different senses of certainty all fit together. By grounding them in hinge certainty, we can see how both the subjective expression of "I know" and the epistemic use of "I know" are part of a larger, integrated picture."

Instead of framing hinges as a metaphysical claim about reality, let’s consider how they function structurally. Just as Gödel’s incompleteness theorems show that certain limits are built into formal systems, Wittgenstein’s hinges show that certain fundamental assumptions are built into our epistemic practices.

In other words, hinges aren’t there to prove anything metaphysical. They’re there to show where our practices of justification find their foundational footing. By drawing a structural parallel to Gödel, we see that these structural boundaries are not arbitrary; they’re intrinsic to how our epistemic language
games work, and hoow systems of belief work generally.

The takeaway being: when we talk about hinges, we’re pointing out that certain stopping points are part of the grammar of justification. They help us see why pushing certain doubts beyond those points stops being an epistemic move and becomes a different kind of game entirely. That’s the structural parallel to Gödel’s insight, and it’s what gives hinges their power.

I guess I can't get away from hinges. :grin:

My perhaps obsessive concern with the appearance/reality question springs from my dislike of the term "reality" in philosophy. It's not that I think there's "more to it than this," but the opposite: I think there's less to it. I don't think we should say that epistemic justification can show us what is "real" -- though see Sam26's point above, about how "truth," "reality" and "constraint" are all aiming at the same role in this discussion. Which is part of why I try to avoid "reality" as a term. I don't think it does much independent work. And at worst, it can blur the distinction between questions about being, and questions about thinking. — J

I don’t think we need to drop the contrast the term is trying to gesture at. The point isn’t “justification shows us the Real,” it’s that justification is answerable to something beyond mere endorsement or conviction. If truth does that job for you, then we can speak in those terms: objective justification is what entitles a claim to be treated as true within a practice, meaning it survives the practice’s tests, correction procedures, and defeaters. In that sense, reality isn’t doing much work. It’s just a way of reminding ourselves that error is possible, that correction is not merely a change of opinion, and that inquiry aims at what's true or justified.

I’m with you on minimizing metaphysical overtones. We can keep the functional point, answerability to constraint, without treating reality as some heavyweight philosophical concept.

If we think a belief is justified and it turns out it isn’t, that is on us for not looking closer, digging deeper (barring unforeseen issues). It might have been a snow-job, trendy, or made up of false data. We might initially think a belief is justified but the work was plagerized (literally mimicked), but that is a judgment of something other than justification (it is still justified, just not by them). It doesn’t help that a weak job of justification is nevertheless done solely, genuinely by the claimant. We only judge their understanding of justification by their demonstration of it. There is no other criteria for understanding because it is not an independent quality of a person, it is a logical distinction—thus why you can have (demonstrated) a pretty good or excellent understanding. You may have training, experience, etc., but still not understand how justification actually works, which is just another way of saying you don’t do it well. It could be a mistake, but if they actually suck at it, no one is going to say they understand it. — Antony Nickles

First, on the plagiarism case. I don’t think it’s right to say, “it’s still justified, just not by them.” If the justification depends on borrowed work they can’t actually own, then what they have is at best a true claim with borrowed support, not objective justification done by them. Objective justification isn’t just that good reasons exist somewhere in the world. It’s that the person can take responsibility for the support in the way the practice requires, including answering for sources, handling challenges, and tracking what it would mean to correct one's claim. Plagiarism is a clean case of mimicking the conclusion while lacking competent justification.

Second, on “there is no other criteria for understanding.” I agree that understanding isn’t a private inner thing. But “demonstration” needs to include more than producing an argument that looks good. In a lot of cases, the difference between doing it well and doing it badly shows up when the person is pressed on mistake conditions: what would count against this, what alternatives are there, what would defeat it, what would you revise if X were true. Someone can generate a weak or even superficially strong justification and still be unable to navigate those checks. That’s why I connect understanding to the practice’s error and correction structure, not to an extra mental property.

I’m with you, viz., understanding isn’t an independent psychological quality. But it’s also not identical to any single performance of justification. It’s competence across the relevant challenges, the ability to sustain objective justification when the practice does what practices do, probe, test, correct, and sometimes expose that what looked like support but wasn't.

Continuing with the final post of the paper.
Post #15

10. Conclusion

The classical model of knowledge as justified true belief remains a sound starting point, not because it answers every philosophical worry, but because it captures the grammar of our ordinary epistemic life. When we call something knowledge, we are not merely reporting a psychological state of conviction. We are placing a belief within a practice of justification and marking that it has succeeded in being true. This is why the model has endured. It reflects what we already do when we distinguish between mere opinion and beliefs that genuinely have standing.

The refinements developed here do not replace that model; they make explicit what the classical formulation leaves implicit. Justification does not operate in isolation. It functions within shared language-games and presupposes a background of bedrock certainties that stand fast for us. These certainties are not items of knowledge, and they are not established by further justification. They are foundational in a non-epistemic sense. They set the conditions under which doubting, checking, and justifying have their point. This is why the demand to justify everything does not express greater rigor. It reflects a misunderstanding of the role that what stands fast plays in our epistemic life.

Understanding, likewise, is not an optional addition to justification; it is internal to it. To justify a belief is to use the relevant concepts correctly within a practice, to move competently among their connections, and to recognize what counts as correction and withdrawal when the practice requires it. The beetle in the box makes the point vivid. If we treat understanding as an inward item, something to which one privately points as the basis of epistemic standing, we detach justification from the criteria that give it life. We do not strengthen knowledge by relocating its basis to the private interior. We dissolve the conditions under which the concept of knowledge functions at all.

These clarifications also reposition the role of Gettier in epistemology. Once justification is understood as a standing within an epistemic practice, disciplined by criteria of correct use and constrained by what stands fast, Gettier-style cases lose their supposed significance. They do not show that the classical model is inadequate, but that many discussions of Gettier rely on a conception of justification that fails to reflect how our epistemic practices actually operate.

To make these points concrete, I distinguished five routes through which justification typically proceeds: testimony, logical inference, sensory experience, linguistic training, and pure logic in its boundary-setting role. These routes are not ranked by epistemic importance. They reflect the order in which justificatory support most commonly appears in our language-games. Alongside these routes, I described three guardrails that express the discipline internal to justification: No False Grounds, Practice Safety, and Defeater Screening. These guardrails do not add new conditions to knowledge. They clarify what it is for support to count as justificatory within a practice and help explain why some beliefs that look well supported fail to have the standing required for knowledge.

The structural parallel with Gödel reinforces the same lesson from a different angle. Gödel’s results show that formal systems have limits that arise from their internal structure, limits that are not defects but conditions of the system’s character. Wittgenstein’s remarks on hinges show that justificatory practices have limits as well. Not everything that makes justification possible can itself be justified. The parallel is structural, not mathematical, but it is instructive. It helps us see that the presence of limits does not entail skepticism. It marks the conditions under which epistemic life can proceed.

The application to artificial intelligence illustrates why these distinctions matter now. Artificial systems can produce true statements, sometimes with impressive reliability. Yet knowledge is not merely the production of truths. It is true belief that stands within a practice of justification, governed by routes, constrained by guardrails, and framed by what stands fast. AI systems can assist human knowers and function as powerful instruments within our epistemic practices. But to treat them as knowers is to blur the grammar of knowledge at exactly the point where clarity is most needed.

What emerges, then, is an account of knowledge that is realist without dogmatism. Truth remains the success condition. Justification remains a practice governed by shared criteria. Bedrock certainties stand fast without becoming items of knowledge. Understanding is not a private achievement but a competence displayed in use. The result is not a new theory erected on top of the classical model, but a clearer view of its working parts and of the background that makes them possible. If there is a practical upshot, it is this: when the appearance of support is everywhere, the task is to recover the discipline of justification and to keep the grammar of “know” clear enough to do its work.

Continuing with paper...
Post #14

9. Objections and Stress Tests

Before closing, it is worth testing the framework against a few cases that are often used to pressure classical accounts of knowledge. The point is not to chase intuitions, but to show how the routes and guardrails clarify why some beliefs have the standing required for knowledge and why others do not, even when the surface looks similar.

Fake barn environment. Consider the case in which a person looks at what appears to be a barn, forms the belief “that is a barn,” and happens to be looking at the only real barn in an area filled with convincing façades. The belief is true, and from the person’s point of view the perceptual situation seems ordinary. Yet the belief lacks the standing of knowledge. JTB+U does not need a new condition to explain this. The belief proceeds through sensory experience, but the environment has altered the standing of that route. Practice Safety is decisive. In a setting saturated with decoys, the belief would easily have been false under nearby variations that the practice treats as relevant. The problem is not that perception stops functioning, but that the ordinary stability required for knowledge is not present. Defeater Screening also matters. The relevant defeater is built into the environment itself, namely that many barn-like objects are not barns. The point is not what the person privately considered, but what standing the belief has within a practice once that defeater is in play.

Testimony under distorted informational conditions. A second pressure point concerns testimony in an environment where repetition is treated as standing. Here the route is still testimony, but testimony has standing only within practices that supply criteria of credibility, provenance, and correction. No False Grounds blocks a common failure. Testimony can look supportive while resting on fabricated reports, altered media, or untraceable sources. A belief placed on such grounds can be compelling and socially reinforced, yet the support is defective at the point where the practice treats the defect as disqualifying. Practice Safety and Defeater Screening complete the diagnosis. A claim can be true by coincidence and widely repeated, while remaining unstable under ordinary informational variation. A claim can also remain persuasive only because relevant challenges are excluded rather than addressed. In either case, what is missing is not sincerity or intensity of conviction, but the standing a belief must have within a practice of justification to count as knowledge.

Human and AI hybrid cases. A third test concerns cases in which a person uses an artificial system as an aid. The temptation is to treat fluent output as knowledge, or to treat the user as having knowledge simply by receiving an answer. The framework clarifies the difference. A person can acquire knowledge with the help of AI only if the belief formed on the basis of the output is placed within a practice of justification that satisfies the guardrails. No False Grounds matters because an output can include invented citations or a false claim doing essential work. Practice Safety matters because slight prompt changes can produce incompatible outputs, which signals instability. Defeater Screening matters because relevant counter-considerations can be present and must be addressed within the practice if the belief is to have standing. This also shows the proper role of understanding. If the output is treated as a substitute for conceptual competence, then the belief can have the appearance of support while lacking the internal structure required for genuine justification. AI can be a powerful instrument within human epistemic life, but that does not collapse the distinction between producing true sentences and knowing.

What these tests show. These cases do not require a patch to JTB. They show that when justification is treated as a public practice with disciplined constraints, the difference between knowledge and lucky success is not mysterious. Truth remains the success condition. What varies is the standing of a belief within a practice, and that standing depends on the routes by which it is supported and on the guardrails that discipline that support. In this way, JTB+U does not replace the classical model. It clarifies what the model already presupposes when we speak carefully about what it is to know.

Continuing with paper...
Post #13

8. Broader Consequences for Epistemic Life Today

The refinement offered by JTB+U is not meant to remain at the level of conceptual reconstruction. Its point is to clarify how our epistemic practices actually work, and to make visible the distinctions that are now repeatedly blurred. In many contemporary settings, the appearance of support is treated as if it were justification, fluency is treated as if it were understanding, and conviction is treated as if it were certainty. The result is not merely disagreement. It is a weakening of the grammar of knowledge, a drift in the very criteria by which we distinguish knowing from persuading, and truth from mere plausibility.

One consequence of the framework is that it restores the place of justification as a public practice. When justification is treated as something private, or as an inner feeling of confidence, the discipline of epistemic life collapses into rhetoric. JTB+U makes explicit that justification depends on shared criteria, on the ability to locate a belief within an established route of support, and on the willingness to submit that standing to correction. This is why the language-games of knowledge depend on practices of challenge and withdrawal. A belief that cannot be corrected within a practice is not thereby strengthened. It is severed from the ordinary conditions under which justification has its point.

A second consequence is that the model clarifies the role of testimony in a world saturated with information. Testimony is not a lesser route. It is among the most common routes in ordinary life. Yet the present environment often treats testimony as interchangeable with assertion, as if the mere existence of a claim in circulation were enough to give it standing. JTB+U makes clear that testimony has standing only within the practices that grant it, and that this standing depends on criteria that are often ignored in modern informational contexts. When those criteria are weakened, testimony does not disappear. It becomes unstable, and epistemic life becomes susceptible to persuasion that imitates the surface of justification.

A third consequence concerns the probabilistic character of justification. Much of what we count as knowledge is not secured by absolute certainty. Our justificatory practices are often graded, and they frequently operate under conditions of limited information. This is not an embarrassment to epistemology. It is part of the grammar of our epistemic life. The mistake is to treat this fallibility as if it implied that knowledge is impossible, or that the classical model must be abandoned. JTB+U instead clarifies how fallibility and knowledge coexist. We can have knowledge without having what philosophers sometimes treat as conclusive proof, because the standing required for knowledge is determined within a practice, under disciplined constraints, against a stable background of bedrock certainties.

This is also where the distinction between the different senses of certainty matters. Subjective certainty is conviction. It can be intense, and it can be sincere, yet it does not settle anything about truth. Hinge certainty is bedrock, it stands fast and makes doubt possible, yet it is not knowledge. Epistemic certainty is the kind of stability a belief can have within a practice of justification, where the belief is resistant to relevant challenge and supported in the way the practice requires. Absolute certainty belongs to logic and necessity. Modern discourse often collapses these into one undifferentiated notion of certainty, and the collapse produces confusion. Conviction is treated as evidence. Bedrock is treated as dogma. Logical necessity is treated as a demand for knowledge. JTB+U separates these senses and returns each to its proper use.

A further consequence is that the framework explains why disagreement can persist even among sincere and competent thinkers. Disagreements are not always disputes over evidence. They can arise from differences in the background against which evidence is assessed, from differences in how concepts are being used, and from differences in which defeaters are treated as relevant. None of this makes truth relative. It shows that our practices of justification are complex and that the stability of knowledge depends on more than the production of arguments. When we recognize this, we are less tempted to treat disagreement as evidence of irrationality, and more able to locate what is actually at issue.

Finally, the framework provides a disciplined response to the current pressure to treat epistemic life as a contest of narratives. Persuasion is not the same as justification. A persuasive claim can be memorable, emotionally forceful, and socially reinforced, while still lacking standing within a practice of justification. JTB+U gives us a way to say this without moralizing. It identifies where the grammar breaks down. The guardrails make the point concrete. No False Grounds blocks claims whose support depends on what is not so. Practice Safety blocks claims that succeed only by coincidence or rhetorical timing. Defeater Screening blocks claims that remain compelling only because relevant challenges have been excluded or ignored.

Wittgenstein’s distinction between criteria and mere signs is useful here. Many things accompany knowledge: confidence, fluency, repetition, even social approval. Yet these are not what justify a claim. They are at best symptoms, and often only disguises. The criteria for knowledge belong to the practice: the routes by which justification is given, the guardrails that discipline it, and the ways a claim can be corrected, withdrawn, or defended when challenged. When those criteria are replaced by signs, epistemic life becomes vulnerable to persuasion that imitates the surface of justification.

In this sense, the account is realist without dogmatism. It affirms truth as the success condition. It affirms the public character of justification. It affirms the necessity of bedrock certainties without treating them as items of knowledge. It affirms fallibility without conceding skepticism. It also encourages a kind of epistemic humility that is not a retreat from truth but an acknowledgement of the limits built into our practices. The point is not that we should doubt everything. The point is that we should recognize what must stand fast for justification to function, and then take seriously the discipline by which beliefs earn their standing as knowledge within the language-games we share.

I agree with you, though many would disagree. I was curious where you would fall on the question. Sounds like we broadly agree on these issues. — Esse Quam Videri

Even if you were omniscient someone would disagree. It means nothing, don't you think?

I feel like I keep repeating myself. When I say, “the conditions that make doubt intelligible,” I mean the basic setup that makes checking and being checked possible. For any practice of inquiry to work, it has to treat some outcomes as settled and others not. Otherwise “I doubt,” “I tested,” and “I corrected myself” become empty statements.

We don’t have to start with the heavy phrase “appearance vs reality.” We can start with something leaner. For instance, settled vs unsettled, correct vs incorrect, passes the check vs fails the check. Those distinctions are already enough to rule out global doubt, because global doubt tries to remove the very idea that anything could ever count as settled.

“Truth vs opinion” can express the same structure, but only if truth means “what would be correct even if no one endorsed it.” If “truth just means “what our group happens to treat as correct,” then the difference between error and correction disappears into sociology. So, the real commitment isn’t a grand metaphysics of Reality with a capital R, it’s the thinner claim that correctness answers to something beyond mere endorsement. Call that truth, call it reality, call it constraint, it’s the same role.

I believe that’s the ontological answer here, not a theory of what exists, but the insistence that inquiry isn’t just opinion-management, it’s answerable to what settles these epistemological questions.

This is a strong reply, and I agree with much of it, but I don't think it gets to the heart of J's concern. My interpretation is that J is not questioning whether global doubt is incoherent, but is asking why grammar should be considered sufficient to settle the issue. In other words, what explains why grammar imposes the limits it does?

I would argue that Wittgenstein's anxieties over transcendental reification make it difficult for him to adequately address this question. I don’t think the deepest explanation can be grammatical. Grammar registers the limits, but it doesn’t generate them. These ultimately need to be grounded in the structure of our normative/epistemic acts themselves: to doubt, correct, or inquire is already to be oriented toward what is the case, toward conditions of fulfillment that distinguish seeming from being. An act of doubt misfires when it asks for fulfillment while cancelling the conditions of fulfillment.

So doubting is a form of judgment guided by reasons. Reasons presuppose the possibility of correcting mistakes by attending to data and testing insights. If you globally deny the existence of any constraint on the data of experience then you undercut the very idea of error, correction, learning and also doubt itself. Inquiry is intelligible only as a self-correcting process of answering questions about what is the case and is therefore rendered unintelligible under the assumption that there is nothing in principle that can settle such questions. — Esse Quam Videri

If someone hears grammar as some self-contained explanation, they might ask: why does grammar have that authority? Your answer is, it doesn’t float free. Grammar is the surface expression of deeper constraints built into what it means to doubt, inquire, and correct at all. In that sense, grammar gives us limits, but the limits are generated by the structure of normative acts, what you call conditions of fulfillment, the difference between seeming and being, and the possibility of error and correction.

This doesn’t really oppose the Witt line, it strengthens it. The hinge point isn’t language settles reality, it’s that global doubt misfires because it cancels the very conditions that make doubt an intelligible, or an answerable activity. The constraint isn’t merely linguistic, and it isn’t a transcendental reification either. It’s built into the logic of inquiry as a self-correcting practice, so if you deny in principle that anything can count as settling questions, you haven’t adopted a stricter epistemology, you’ve made the whole enterprise of error, learning, and correction unintelligible.

I’d frame it this way, grammar is sufficient to diagnose the misfire because of how it tracks the role our concepts play, but a deeper explanation is much morre practical and normative, the structure of what it is to seek fulfillment, be answerable to correction, and distinguish appearance from reality. That’s exactly why global skepticism collapses. Hopefully this answers your concern.

Continuing with paper...
Post #12

7. JTB+U and Artificial Intelligence: Why AI Does Not “Know”

The present interest in artificial intelligence has brought an old temptation back into view. We are inclined to treat fluent performance as if it were knowledge, and to treat the production of correct sounding answers as if it were understanding. This temptation is understandable. The outputs of large language models can resemble the surface of competent human speech. They can summarize, explain, and argue, and they can do so in a way that often passes casual scrutiny. Yet the resemblance is grammatical only at the level of appearance. When we look more closely, we see that the ordinary criteria for knowledge are not satisfied, not because the machine lacks a private mental state, but because it does not stand within the practices that give the concept of knowledge its use.

Truth remains the success condition for knowledge, and nothing in what follows weakens that point. An artificial system can produce a true statement, sometimes with striking reliability. But knowledge is not merely the arrival at truth. Knowledge is true belief that stands within a practice of justification, and the standing is not a decorative label. It depends on the routes by which the belief is supported, the guardrails that discipline that support, and the background of bedrock certainties that makes the whole practice possible. This is the first reason the language of knowledge becomes slippery when we apply it to machines. The system produces assertions, but it does not participate in the language-games in which assertion, challenge, withdrawal, and justification have their life.

This is also where the role of bedrock certainties becomes decisive. Human justification presupposes a background that stands fast for us. These certainties are not items we know. They are the inherited conditions under which doubting and knowing take place. They form a hierarchy in the sense that some stand deeper than others, and they are displayed in action rather than defended by argument. The point is not that a machine lacks a set of stored assumptions. It is that the machine is not trained into a form of life in which such certainties function as the background of justification. An AI system does not stand within the practices that define what counts as a mistake, what counts as correction, and what counts as the withdrawal of a claim. It can be updated, constrained, and fine-tuned, but this is not the same as occupying the human space in which bedrock certainties show themselves as what stands fast.

The five routes also clarify the difference. When a person justifies a belief through testimony, inference, sensory experience, or linguistic training, the support is situated within a practice in which the believer can be held responsible to standards. These standards are public and they include the possibility of being corrected in the relevant way. A language model can mimic the outward form of these routes. It can cite sources, draw inferences, and use perceptual language, but these are linguistic gestures, not placements within the practice itself. The model does not have testimony in the human sense, since it is not a participant in the practices that give testimony its standing. It does not infer in the human sense, since it does not operate with the conceptual competence that makes an inference a movement within a language-game rather than a pattern of token transitions. It does not perceive, and so it does not have sensory experience as a route of justification. It displays linguistic training in the limited sense that it has been trained on linguistic material, but this is not the kind of training by which a human learner comes to grasp the use of a concept within a form of life. It is closer to the acquisition of a statistical profile of usage than to the possession of a concept.

This is why the distinction between statistical competence and conceptual competence matters. A model can be statistically competent, in the sense that it produces language that fits patterns in its training data. It can do this at scale and with impressive fluency. But conceptual competence is not the possession of patterns. It is the ability to use a concept correctly within a practice, to respond to correction, to recognize when a challenge is relevant, and to withdraw a claim when the practice requires it. These are not private mental achievements. They are displayed in the way one stands within a language-game. The machine can be made to output a retraction. It can be prompted to list possible objections. Yet these are outputs, not the standing of a belief within a practice of justification.

The guardrails bring the point into sharper focus. No False Grounds matters because a model can generate support that looks acceptable and yet includes a false claim doing essential work. Practice Safety matters because a model’s correct output may be the result of a fortunate match rather than stable standing, especially in domains where the system has not been constrained by reliable sources. Defeater Screening matters because, while a model can generate lists of objections, it does not occupy the public discipline in which defeaters arise as challenges that change the standing of a belief. The model can simulate the discourse of justification, but it does not stand within a practice where its claims are owned, corrected, and withdrawn in the way that our language-games require.

None of this implies that AI is useless in epistemic life. The opposite is true. Artificial systems can be powerful instruments within human practices of justification, especially when their outputs are constrained by reliable data and when they are treated as aids rather than as knowers. They can help gather information, surface patterns, and organize arguments. But this usefulness does not collapse the grammatical distinction between producing true sentences and knowing. To treat the machine as a knower is to project the grammar of our concept of knowledge onto something that does not meet its criteria of use.

This is why JTB+U is especially valuable in the present environment. It gives us a disciplined way to distinguish persuasion from justification, fluency from conceptual competence, and the appearance of support from genuine standing within a practice. It also helps explain why the language of certainty is often misused in discussions of AI. A model can produce confident sounding claims, and this can resemble subjective certainty. But hinge certainty is not confidence, and epistemic certainty is not mere persistence under repetition. The kinds of certainty that matter to knowledge are rooted in practices and in what stands fast within them. The machine does not inhabit that structure, even when its outputs resemble the surface of a human epistemic performance.

For these reasons it is better to say that artificial systems can produce true statements, and can assist human beings in practices of justification, without saying that they know. The temptation to speak otherwise is understandable, but it blurs the grammar of knowledge at exactly the moment when we most need it to be clear.

Continuing with paper...
Post #11

6.4 The Guardrails as Clarifications of Justification

Taken together, these guardrails clarify the shape of justification as it functions. No False Grounds excludes cases in which the support is defective at a crucial point. Practice Safety excludes cases in which truth is reached only by luck. Defeater Screening excludes cases in which the belief cannot retain standing under relevant challenge. None of this adds a new condition to JTB. It makes explicit the discipline that our justificatory practices already embody.

This is also where the role of understanding, as I use the term, becomes sharper. Understanding is not a separate achievement layered on top of justification. It is the conceptual competence through which justificatory support has its proper use within a language-game. The guardrails describe the constraints that this competence must respect if a belief is to have the standing required for knowledge. When a belief violates these constraints, it may still be true, and it may still feel compelling, but it does not stand as knowledge within our practices of justification.

With these guardrails in view, the classical model is not weakened but clarified. We can see why some beliefs that look well supported nevertheless fail to constitute knowledge, without treating Gettier-style cases as decisive objections. The next step is to apply this clarified grammar to contemporary pressures, including the temptation to describe artificial systems as knowers and the need to preserve the ordinary concept of knowledge in an information environment that often rewards persuasion over justification.

Rule-following brings the point into sharper focus. To use a concept correctly is not to consult a private rule, nor to match an inner image, but to have been trained into a practice where “correct,” “mistake,” “same,” and “different” have their use. The standards that govern justification are therefore not hidden in the mind. They are displayed in our shared procedures of correction and agreement, in what counts as getting it right and what counts as needing revision. This is why justification is public in its grammar even when it concerns matters that are privately experienced. If there were no practice in which correctness could be shown, there would be no sense to the claim that a belief is justified.

Of course there is formal logic, which has it uses, but I would think more important is the internal logic of a practice, some of which are particular versions of ones you mention. As I said above, there are criteria for what we consider to be an apology, a sufficient one to categorize it as an apology. There are constraints for correctness, boundaries for appropriateness. The implications of certain acts within a practice have specific implications. All this is to say that formal logic is but one practice, no better, more important, or more necessary/powerful than others. Of course, its independence and certainty make it more desirable. — Antony Nickles

Formal logic is one practice among others, and a lot of what governs our epistemic life is the internal logic of practices, what counts as an apology, what counts as correction, what counts as evidence, and so on. That’s why I talk about objective justification as part of the five ways we justify our beliefs, rather than treating justification as a purely formal relation between propositions.

Formal logic isn’t more important in the sense that it's some master key to knowledge, but it has a particular role. It doesn't supply the whole grammar of justification on its own, because most practices involve standards of relevance, error, correction, and defeaters that aren’t reducible to formal entailment. I’m happy to say, logic is indispensable for certain jobs, but it’s not the whole story, and it shouldn’t be treated as the model for every kind of justification. Finally, I make a distinction between pure logic and the logic of deductive and inductive reasoning.

I agree with your “some are and some aren’t.” The stopping point isn’t always as clearly delineated as a finish line. Take “there is an external world.” The point isn’t that this is a proposition we happen to feel very confident about. It’s that the skeptical demand to doubt it globally can’t be carried out without using the very grammar it is trying to suspend. To be able to doubt in a way that counts as doubt, you need criteria for checking, what would count as error, what would count as correction, and what would count as a defeater. But those notions are already world involving, they presuppose stable objects, re identification across time, public conditions of correction, and a contrast between appearance and reality. The global doubt doesn’t undercut a particular belief, it undercuts the practice conditions that give doubt its meaning. That’s why it’s hinge territory.

As for the cultural question, I think cultural conditioning in a limited sense is only natural (how much depends on the context). Different cultures can weight different routes, emphasize different norms of authority, etc. But that’s not the same as saying the grammar of justification is an empirical study of how this group thinks. The hinge point is structural, any community that has a practice of giving and asking for reasons, correcting mistakes, and distinguishing seeming from being will have some things that stand fast in order for the practices to function. So yes, there can be variation in which commitments play hinge roles and how they’re expressed, but the need for a bedrock background isn’t optional, and it’s not reducible to psychology. Just as the hinge background of chess (board and pieces) aren't optional if you're playing traditional chess.

A lot of recent hinge work has been shifting away from hinges as a magic bullet against skepticism (I don't claim it as a magic bullet, but I do think it shows how global skepticism misfires) and toward practice facing issues: trust, testimony, deep disagreement, and the way background commitments shape what even counts as evidence and correction. Coliva’s work on “hinge trust,” and the newer “social hinge epistemology” literature, are good examples.

Where I separate myself. Contemporary hinge epistemology often gets stuck arguing over one global theory of what hinges are, or over whether hinge frameworks really deliver the anti-skeptical payoff people want. You can see that pressure in recent work that argues the prominent “framework” formulations don’t succeed on their own terms. My paper isn’t mainly trying to win that internal hinge debate. I use hinges to mark the structural background of epistemic assessment, and then I focus on what actually disciplines claims to propositional knowledge inside language-games and forms of life.

My distinctive move: I start with JTB as a familiar grammar for propositional knowing, then I tighten the “J” condition with explicit guardrails, and I treat “+U” as a clarification of justificatory standing, not a fourth ingredient. The separate the person who can track mistake conditions, defeaters, and correction, from the person who can only recite the right conclusion. That’s also why testimony matters so much in my account, it’s not a lesser substitute for real knowledge, it’s a primary route that has to be disciplined by the same practice governed rules.

One more divergence, and I’m happy to own it. I treat hinges as arational and foundational, and I also think they carry ontological commitments. That’s stronger than a purely “methodological” reading, but it explains why global skepticism misfires, viz., it tries to call into question the very background that gives doubt, checking, and correction their sense. (Whether you want to call that a “solution” or a “dissolution” is secondary.)

I’m not addressing knowledge as a skill here, knowing how to build a cabinet, assemble a gun, play a tune, etc. That’s important, but it’s a different topic. My focus is propositional knowledge, claims of the form “I know that p,” where questions about justification, error, correction, defeaters, and Gettier pressures actually arise.

On that score, I agree that knowing and understanding aren’t inner objects we possess. They’re statuses we attribute within practices, and practices have standards for what counts as getting it right and what counts as correction. That’s why I talk about justificatory standing rather than private confidence or conviction.

Where the “+U” bites is this: in the propositional cases I’m focused on, understanding is competence with mistake-conditions. It’s being able to say what would count against the claim, what would defeat it, and what would correct it. That’s what keeps justification from collapsing into citation, authority, or lucky success.

And on authority: yes, propositional knowledge often rests on testimony and expertise, but authority isn’t self-certifying. It’s answerable to provenance, track record, and defeaters. If someone can’t track those, then there's an obvious problem, and that is exactly what many Gettier style worries are seeming to expose.

Continuing with paper...
Post #10

6.3 Defeater Screening
The third guardrail concerns challenge. Justification is not only a matter of placing a belief within support. It is also a matter of whether that standing survives relevant disruption. Defeater Screening names the fact that, within our practices, certain challenges count as undermining, and when they are present and undefeated the belief no longer has the standing required for knowledge.

This does not mean that one must answer every skeptical possibility. Our language-games do not treat every imaginable doubt as relevant. What matters is the kind of defeater that the practice itself recognizes as bearing on the standing of the claim. Sometimes a defeater shows that the grounds were false. Sometimes it shows that the route was misapplied, that the inference did not hold, that the perceptual situation was misleading, that the testimony lacked standing, or that a concept was applied outside its proper range. In each case the issue is not private reflection but public standing. A belief is not counted as knowledge when it stands under an undefeated challenge that the practice takes to be disqualifying.

Defeater Screening therefore belongs to the grammar of justification. It is part of what it is for a belief to stand properly within a practice, rather than to be held in a way that collapses under the first relevant counter-consideration.

No, the hinges are neither habitual nor pragmatic/convenient. But . . . "By which we take ourselves to be in contact" -- that's the rub. What is the practice being described which can result in contact with reality, aka, that which ontology studies? This question isn't limited to Witt-related thought, of course, but nor do the Wittgensteinian moves render it unproblematic.

Another way of saying it: To carry ontological commitments -- which I agree that hinges do -- is not to be part of what ontology studies or describes. There remains the question of the status of our epistemic practices as they relate to what we're pleased to call "reality." That is an Ur-metaphysical question, so possibly out of bounds for the Witt line of thought? — J

I think that’s the right pressure point, and I don’t want to dodge it with Wittgenstein slogans.
When I say by which we take ourselves to be in contact with reality, I’m not trying to smuggle in a practice that gives us access to Being. I mean something more minimal, i.e., that our ordinary epistemic practices already operate with a contrast between getting it right and getting it wrong, between correction and mistake, between appearance and reality. Hinges are part of what makes that contrast intelligible. They don’t secure contact with reality, they are the background commitments that make the very idea of contact, miscontact, error, and correction usable.

So, I agree that carrying ontological commitments is not the same as doing ontology. Hinge talk isn’t an ontology and it doesn’t settle ontology. What it does is clarify the foundational/bedrock commitments under which ontological discourse, or any discourse can even get off the ground. In that sense it’s neither merely a pragmatic convenience nor a metaphysical proof. It’s a claim about the grammar (Wittgensteinian grammar of course).

On the fundamental metaphysical question about the status of our practices in relation to reality: yes, that question remains. Wittgenstein doesn’t abolish it. What his line of thought does is block a certain way of posing it, the way that tries to demand a justification for the whole framework while still using the framework’s notions of justification, evidence, and correction. If you ask the Ur-question as a metaphysical project, fine. My point is just that it’s no longer an ordinary epistemic demand, and it can’t be answered by ordinary justificatory moves, because those moves presuppose the very standing-fast background under discussion.

I’d say it this way. Hinges have ontological commitments, and in that sense they touch ontology. But they don’t deliver ontology. They set the stage on which ontological arguments can be intelligible, and they explain why some global demands for justification misfire: not because reality is off limits, but because the demand is asking for a kind of validation that cannot be supplied without circularity or infinite regress.

I don't want to make the thread all about hinges, but I also don't want to not take questions about hinges.

My own view is different, but I think that's Wittgenstein's take as I interpret it.

A rule does not interpret itself. Yet we have rules that set up novel interpretations. Following a rule can involve treating something as if it were something more. The move is essentially to build a new language game on the back of another. And something like this seems implicit in a form of life. The whole remains embedded in human activity, in a form of life. — Banno

I agree with most of that.

Wittgenstein does think his approach bears on the foundations of mathematics: of course, the temptation is to imagine that the rule, or the proof, carries its own application and its own interpretation independent of what we actually do. A rule doesn't interpret itself, it's not an aside, it's aimed at that picture.

At the same time, youa'e right that we can introduce further rules that effectively stabilize new ways of speaking. We can take an earlier practice and add a counts as norm that extends it. In this sense, following a rule can include treating a construction as if it were something more, because we have adopted criteria that make that treatment correct within the extended game.

But the Wittgensteinian idea is that this isn't a metaphysical ascent to a realm of completed entities. It's a reworking of our practice (what we do), still embedded in human activity and a form of life. The novelty comes from what we now allow as a correct move, not from discovering a new kind of object behind the calculus.

One follow on question is the extent to which this is a reflection of what Wittgenstein is getting at in PI  §201. Sam26 may well insist that Wittgenstein had no such thing in mind. I'm not so sure. — Banno

Okay, I guess I do have something more to say. I can see why @Banno would connect it to PI 201, at least as an analogy. PI 201 is about the gap between a rule and its application; the worry is that any finite formulation can be made to fit different continuations unless our practice fixes what counts as going on correctly, which is close in spirit to the worry about ellipses and “…” in the infinity case.

But I'd be careful about saying Wittgenstein had the real numbers or completeness axioms in mind there. In 201 he is not doing foundations of analysis; he is diagnosing a philosophical temptation: the idea that the rule must contain its own application as rails laid to infinity. His answer is that correctness is in the shared practice of following a rule, not in a ghostly extra fact.

If the link is: “reifying a procedure with a counts as norm is one way of making our practice explicit,” then yes, that resonates with 201. But if the link is: “201 is really about completeness or model theory,” I think that is a stretch. The Wittgensteinian moral is still that a rule does not interpret itself, and neither does an ellipsis. What settles the continuation is the rule plus the practice that gives it grip.

:up:

I don't have much more to say on the subject. Thanks.

First, on “stand fast.” I do think this has ontological bite. Hinges aren’t merely linguistic habits or conversational conveniences. They are bedrock commitments by which we take ourselves to be in contact with reality. They function as conditions of possibility for inquiry, but precisely because of that they carry ontological commitments: “there is a world,” “objects persist,” “other minds exist,” and so on are not neutral placeholders. They are ways of taking reality to be foundational (not foundational in the traditional sense).

Here’s the crucial point: hinges don’t function as claims inside our epistemic framework, they function as the framework. They aren’t supported by evidence in the ordinary way, and they aren’t normally overturned by ordinary counterevidence, because they are what make evidence, counterevidence, mistake, and correction intelligible in the first place. If a hinge were routinely up for the same kind of assessment as ordinary propositions, if it had the same kind of defeaters and the same criteria of confirmation as the claims we test within inquiry, then it wouldn’t be doing hinge work. It would just be another hypothesis among hypotheses. That’s why doubting everything at once doesn’t produce a deeper epistemology, it dissolves the background that makes doubt possible.

Second, on whether Witt is merely “innocently noting a fact.” I think this is where the hinge point is easy to miss. It can sound as if Witt is mainly giving a recommendation, “stop here or you’re doing nonsense.” But a hinge isn’t a proposition we choose to stop with because we’re tired of explaining. It’s what has to stand fast for the practice of giving and asking for reasons to have traction at all. So when Witt indicates a stopping point, the point isn’t “here is where I recommend you stop.” It’s “past this point your demands no longer operate as epistemic demands.” The “ought” is internal to the practice, not moral policing. Your race analogy captures it: past 500 yards you may still be running, but you’re no longer running that race. Likewise, you can refuse to stop, but then you’ve shifted from ordinary epistemic assessment into a different philosophical ambition, a demand for an ultimate ground.

That’s also why everyone isn’t automatically a Wittgensteinian. The disagreement isn’t whether practices have hinges, they do. The disagreement is where to locate them, how to describe them (I think there's a hierarchy of hinges), and whether someone’s philosophical demand has genuinely left the space of epistemic assessment or is still a legitimate request for further justification within it. My paper is trying to make those boundaries explicit without using hinge talk as a conversation-stopper.

Finally, I agree completely that unclarity about justification is a problem for Witt and for me. That’s why I’m writing the paper. Hinges are unavoidable, and they mark a legitimate limit: you can’t treat justifiication as an all-purpose demand that reaches all the way down. What you can do is make the standards of justificatory standing explicit, error, correction, defeaters, and the role of understanding in tracking mistake-conditions, so that “this is where we stop” isn’t a gesture, it’s a disciplined account of how our epistemic life actually works.

I think you’re right about how quickly the language of infinity goes into time and process. But “process” can be doing two things, viz., it reports our activity, calculating and checking, and it can mark a feature of the rule, that there is no last step built into it. Calling it “unfinished” need not mean a temporality is at work, it can mean the grammar contains no stopping point.

On your Aristotelian comment, Wittgenstein might ask what “actual” and “potential” are doing in our language, and whether they clarify the use of symbols or just swap one picture for another.

And on existence, I am not denying that numbers exist. I’m blocking a slide in what “exist” means here. In mathematics, “exists” is governed by proof and use, not by the idea of a completed infinite inventory sitting somewhere. So, the rule can be firm without that extra picture.

The philosophical problem isn’t infinity; it’s the pictures our words seem to imply when we remove them from the practice that gives them sense. When we keep the use fixed, the mystery largely disappears.

Continuing with paper...
Post #9

6.2 Practice Safety

The second guardrail concerns stability. In ordinary life we distinguish between a belief that is true and a belief that is true in a way that is secure enough to count as knowledge. Practice Safety names this distinction without turning it into a demand for infallibility. A belief is practice safe when, given the way it is supported, it would not easily have been wrong under the nearby variations that the practice itself treats as relevant.

This matters because a belief can be true by luck, and yet still look supported. In such a case the belief has a kind of success, but it does not have the standing of knowledge. Knowledge is not merely arriving at the truth. It is arriving there in a way that fits the discipline of a practice of justification. Practice Safety captures the sense in which our language-games require more than coincidence, not by imposing an abstract condition, but by reflecting the ordinary difference between what is dependable and what merely happens to work out in a single instance.

The point applies across all five routes. Testimony is practice safe when the source and the circumstances supply stable standing for the report, not a fortunate accident. Inference is practice safe when the transitions hold in the way the practice requires, not only in the one case where they happen to land correctly. Sensory experience is practice safe when the conditions are not the sort that regularly generate error signals. Linguistic training is practice safe when the relevant concepts are applied in the way the language-game calls for, not in a way that merely sounds right. Pure logic, in its boundary setting role, is practice safe when it draws limits of sense correctly, rather than excluding or permitting claims by a mistake in grammar.

Practice Safety therefore records a feature of our epistemic practices that many discussions of knowledge ignore. We do not treat every true belief with surface support as knowledge. We treat knowledge as something that stands within a stable pattern of justification, stable in the sense our practices recognize.

How could "the next step" not imply "a thing happening in time"? — Metaphysician Undercover

Because next can mean two different things.

1) Next in the definition (logical next).
In mathematics, next often just means “the item with the next label in the sequence.” It’s part of how the rule is set up, so if you tell me where you are, the rule tells you what counts as the next one. That doesn’t require anything to be happening in time.

2) Next in our activity (temporal next).
When you or I actually work it out on paper, then there really is a next moment: first this line, then the next line, etc.

So, the word next doesn’t automatically imply time. It can be about the structure of the sequence, or it can be about our act of calculating it.

Continuing with paper...
Post #8

6. Guardrails and the Discipline of Justification

The five routes describe the ordinary ways in which justification proceeds. They show how a belief can be supported within our language-games, through testimony, inference, sensory experience, linguistic training, and the boundary-setting role of pure logic. Yet a route is not, by itself, a guarantee that a belief has the standing required for knowledge. A belief can travel along one of these routes and still fail to count as knowledge because something in the justificatory situation does not have the right shape.
This is why it is helpful to make explicit a set of guardrails, not as additions to the classical model, but as clarifications of what our practices already require when we speak carefully. These guardrails articulate constraints that belong to justification as it functions within a practice. Their point is grammatical. They mark what it is for justificatory support to count as support within a language-game, rather than as something that merely looks supportive from a distance.

I call these guardrails No False Grounds, Practice Safety, and Defeater Screening.

6.1 No False Grounds

The first guardrail is straightforward. A belief cannot be justified when the support doing the work is false in a way that matters to the case. This is not a demand for certainty. It is a demand that the grounds on which the belief is placed in standing not be defective at the point where the practice treats the defect as disqualifying. When a belief is supported by a mistaken identification, a fabricated report, a misdescribed circumstance, or a misapplied concept, the belief may still be true, but its standing is not the standing of knowledge. It is not properly grounded within the practice.
This is one reason Gettier-style constructions do not function as counterexamples to JTB. They rely on the appearance of justificatory support while allowing false grounds to do essential work. Once justification is understood, as argued above, as a standing within an epistemic practice rather than the mere presence of supporting considerations, the pressure of these cases dissolves. What they reveal is not a defect in the classical model, but the need for greater care in describing what counts as genuine justification.

No False Grounds therefore clarifies the discipline internal to our epistemic life. It is not a philosophical invention. It is already present in the way we withdraw standing when a belief is traced back to something that is not so.

What bothers me is that we seem driven to talk about processes in connection with infinity, as you do in the first sentence. But does such a concept make sense in the context of mathematics? Or does it mean that constructivism must be true, at least in the context of infinity? — Ludwig V

In math, process doesn’t have to mean a thing happening in time. It may just mean a rule, a precise recipe that tells you how to get the next step, or how to compute the nth term. Infinity shows up because the rule has no final step.

That doesn't itself prove constructivism. Math is just comfortable saying this exists even when you don’t have a method to build it. Constructivism demands the method, at least that's my take.

Wittgenstein’s point is to be careful not to treat the infinite as a finished object sitting out there. What we really have is a rule and the proofs we proceed with. That leans constructive in spirit, but it isn’t a knockdown argument that constructivism must be true.

As for why a “God-hinge” is harder to establish than “there is a world”: my answer is that the world-hinge is not something we arrive at by argument (i.e., we don't arrive at a hinge epistemically), it’s displayed in the most basic operations of inquiry. It’s not a thesis inside the practice, it’s part of what makes the practice of checking, correcting, and learning possible at all. That’s why it isn’t typically up for debate in the same way, and why someone who “denies the world” is usually no longer playing the game of justification in any recognizable sense.

By contrast, “God exists” is, for most people, a substantive metaphysical claim that remains active in the space of assessment. People can vigorously deny it while still fully participating in the practices of evidence, error, correction, and defeater sensitivity. That fact is exactly what makes the “God as hinge of rationality” project such a high bar. If the denial doesn’t collapse the grammar of justification, then the claim hasn’t shown itself to be a hinge in the Wittgensteinian sense.

On “must they be wrong” and “what’s the persuasion for ‘you should stop at X’”: I don’t think the hinge idea is a recommendation about where one ought to stop, as if Wittgenstein is issuing a rule. It’s a description of where our justificatory practices actually do stop, where reasons run out and the background stands fast. You can refuse to stop, but at some point the demands cease to be ordinary justificatory demands and become a different kind of philosophical ambition, for example a metaphysical demand for an ultimate ground. That ambition can be coherent, but it’s no longer the same as ordinary epistemic judgements.

On your last question, yes, I think you can consistently hold that God is ontologically necessary without claiming God is grammatically necessary for rationality and justification. That’s basically the difference between a metaphysical thesis and a thesis about the conditions of intelligible justification. A person could say: “God is the ground of Being,” while also saying: “human justificatory practices, as practices, can operate without explicitly presupposing that claim.” In such a case, God would be ontologically basic on their view, but not a hinge of rationality in the Wittgensteinian sense.

And that’s why I keep separating two things, viz., the ontological project asks what must exist for anything to exist. The hinge project asks what must stand fast for our practices of doubt, evidence, error, and correction to be intelligible. Those projects can converge, but they don’t automatically converge, and the burden is on the theologian to show that they do.

There's some repetition in the paper I can cut out. Also, I think I need to clarify a couple of ideas.

Continuing with paper...
Post #7

5. The Five Routes of Justification in Practice

Justification in our epistemic life does not take a single form. It moves along routes that reflect how our language-games operate, each showing a way in which a belief can acquire the standing required for knowledge. These routes are not methods competing for priority. They mark different moments at which justificatory support is given within a practice. Their unity lies in the grammar of justification rather than in any shared procedure.

Testimony is the route on which we rely most naturally. Much of what we count as knowledge depends on the word of others, taken within practices that give their claims standing. Testimony is not a lesser form of justification. It is part of the training through which we learn to distinguish the credible from the questionable and to recognize when a speaker’s role, authority, or position within a practice makes their statement a source of support. Testimony functions because our language-games already contain criteria for when a statement may be accepted.

Logical inference shows a different movement. Here, the standing of a belief comes from its relation to other propositions. Patterns of inference, whether deductive or inductive, reflect the conceptual links we inherit through training. They do not impose external rules on thought but express the grammar of our concepts. To follow an inference is to move correctly within a practice whose standards are already in place.

Sensory experience provides justification when what we perceive aligns with how things are described in our language-games. Perception does not stand outside our practices as an independent foundation. It is shaped by our capacity to apply concepts, to distinguish appearance from reality, and to place what is seen within the background that stands fast for us. Sensory experience supports belief because our training has already taught us how perceptual reports function within the practice.

Linguistic training is often overlooked, though it is involved in nearly every case of justification. To possess a concept is to be able to use it correctly, and much of what we call knowledge depends on this competence. When a belief rests on the proper application of a concept within a language-game, its standing reflects the training that guides our use. This route makes explicit why understanding is internal to justification rather than something added afterward.

Pure logic occupies a more limited role, though it remains important. It does not track experience or testimony, nor does it guide ordinary inference. Its task is to clarify the structural limits of what can coherently be said. Pure logic justifies by ruling out what cannot find a place within our language-games. It draws the boundary of sense rather than supplying support for particular beliefs.

These routes do not form a hierarchy. Each contributes to the standing a belief must have to count as knowledge, and each operates within the background of certainties that makes justification possible. JTB+U clarifies how these routes function together by showing that no route, taken on its own, guarantees justificatory standing. To see how that standing is disciplined in practice, we must also attend to the constraints that govern when support counts as support. That task is taken up in the next section.

I'm sure he would. But it is not so easy to rest content with "this process can continue without end". On one hand, we think that the result of the function for each value is "always already" true. On the other hand, we feel that the result is not available until the function has been applied to each value. What makes this game even more puzzling, is that it seems we can know things about the whole sequence without working out the results of the whole sequence. The first example of this is that we can know that the process can continue without end. — Ludwig V

Ya, I agree it’s hard to rest content with “the process can continue without end,” i.e. we feel a real pull in two directions. On the one hand, once the rule is fixed, we want to say the value at each input is “already settled.” On the other hand, we want to say the value is not actually there for us until we run the rule at that input. This is exactly where the philosophical itch lives.

Wittgenstein, as I read him, is to separate “already settled” from “already computed.” The rule determines what counts as the correct next step, and in this sense the sequence is fixed, but it doesn't follow that the whole infinite list exists as a finished object waiting to be inspected. The “always already” feeling comes from the grammar of the rule, not from possession of an infinite completed totality.

The point about knowing things about the whole sequence without grinding through each case is just more of the same. We can know global facts because they are proved from the rule, for example, “this can go on without end” isn't discovered by checking every term, it’s a consequence of how the procedure is defined. The puzzle is real, but the solution isn't to posit a hidden, completed infinity in the background. It’s noticing what proofs actually license us to say about a rule-governed practice.

A rule can fix the standards for correctness without implying that the entire infinite list exists as a finished thing. We often feel “it’s already there” because the rule is firm, but what’s “already there” is the method, not a completed infinite inventory.

Even in set talk, nothing magical follows: we can define endlessly many infinite sets (like the rationals between a and b), but that’s just a feature of our notation and rules. The mistake is to treat those definitions as a tower of new “infinities,” instead of keeping “infinite” tied to the procedure.

Continuing with paper...
Post #6


4. Hinges and Limits: A Structural Parallel with Gödel

Our justificatory practices do not begin from nowhere. They move within a setting of certainties that stand fast for us and form the background against which our judgments make sense. These certainties do not arise from inquiry. They are the conditions from which inquiry proceeds. Wittgenstein’s image of a river with a relatively fixed bed helps bring this structure into view. Some propositions shift with experience, while others lie beneath that shifting surface, not as items known but as parts of our form of life. They are the points at which doubt gives out.

This helps explain why justification has limits that are not defects. Doubt always operates against a background that is not itself in doubt. To imagine otherwise is to lose the distinction between doubting and knowing. Hinges cannot be justified, and they do not need justification. Their role is not to supply evidence but to provide the stability against which the difference between evidence and error is intelligible. They do not enter the space of justification; they make that space possible.

A useful parallel can be drawn here with Gödel’s incompleteness results, understood in a strictly structural sense. Gödel showed that any sufficiently rich formal system operates against constraints it cannot, by its own rules, fully account for or secure. This is not a defect in the system but a consequence of its being rule-governed at all. The relevance of this result for epistemology is not mathematical and does not concern the formal incompleteness of human knowledge. Rather, it serves as an illustration of how practices governed by rules depend on background conditions that are not themselves established by the standards those practices deploy. Justificatory practices are similar in this respect. They cannot justify everything they rely on, not because of oversight or failure, but because justification itself requires a background that stands fast. Hinges mark these internal stopping-points. They are not axioms, and epistemology is not a formal calculus, but the comparison helps make clear how limits can arise from within a practice without undermining its authority or coherence.

This perspective clarifies the place of bedrock certainties. They are not hidden assumptions or unexamined beliefs. They are the inherited background against which justification takes its form. To recognize them is not to adopt dogmatism but to acknowledge the grammar of epistemic life. Doubt cannot extend everywhere, not because we refuse to question certain things, but because the possibility of questioning presupposes a foundation that is not itself the outcome of justification. The stopping-points are part of the practice.

This insight strengthens the refinement offered by JTB+U. Justification requires a background that is not itself produced by justificatory means, and understanding involves navigating the concepts that operate within that background. These limits do not undermine the classical model of knowledge. They show the conditions under which it can function. Gödel’s work reminds us that structured practices have horizons. Wittgenstein reminds us that epistemic life is no exception. Hinges mark the horizon of justification and teach us what must remain fixed for the river of belief and doubt to flow at all.

One way to describe what this paper asks the reader to do is to speak of aspect-seeing. Nothing new is added to our evidence by making these distinctions explicit. What changes is the way we see the epistemic landscape. We stop treating justification as if it were an inner glow that accompanies a belief, and we see it as a public standing within a practice, governed by routes, constrained by guardrails, and framed by what stands fast. The shift is not a new theory but a clearer view of the grammar that has been at work all along.

If there are affinities with pragmatism or with later analytic work on normativity and practice, I’m happy to acknowledge them. But I’m not trying to force Wittgenstein into Hegelian inferentialism. I’m using later Wittgenstein to keep JTB anchored in how our practices actually operate, and to keep the discussion aimed at epistemic certainty, not Cartesian absolute certainty.
— Sam26

Post-Sellarsianism is defined by where one locates normativity, which seems to be the same site you situate it, in public justificatory standing governed by mistake-conditions, defeaters, and correction. Like the post-Sellarsians, you treat JTB as a legitimate starting grammar, whereas Wittgenstein aims to dissolve this starting point. Wittgenstein uses hinges to stop explanation, not to underwrite it. Once hinges are recruited to keep JTB “anchored,” they have been absorbed into a normative architecture. That architecture is Sellarsian in spirit even if it is anti-foundational in tone. — Joshs

That’s a fair challenge, and I’ll concede the affinity while rejecting the conclusion.

If “post-Sellarsian” just means locating normativity in assessable standing, mistake-conditions, defeaters, and correction, then yes, my account has overlap. But overlap isn’t identity. My use of Wittgenstein is meant to limit that normative architecture, not to extend it.

Here’s the key point: hinges aren’t part of justificatory standing in my framework. They aren’t reasons, warrants, or items that get graded as justified or unjustified. At the same time, I do think hinges are foundational, but not in the classical sense of “foundations” as justified premises from which knowledge is derived. Their foundational role is structural: they’re conditions of possibility for inquiry and justification. They stand fast as the background against which evidence, error, correction, and defeaters can have a role at all. So they’re foundational like the river-bed is foundational to the flow, not like axioms are foundational to a proof.

When I say hinges “anchor” JTB, I don’t mean they underwrite it with deeper reasons. I mean they prevent the J in JTB from being misconstrued as a Cartesian demand for foundations. Hinges mark where justificatory talk stops, they constrain the reach of “why?” questions, they don’t answer them.