Why Perfect Tracking Isn't Knowledge: Williamson's Refutation of Sensitivity

The Intuitive Appeal

It seems obvious: if you know something, then if it were false, you wouldn't believe it. If I know the tree isn't 666 inches tall, then if the tree were actually 666 inches tall, I wouldn't believe it's not.

This intuition—called sensitivity—appears to capture something essential about knowledge. It looks like knowledge requires a kind of perfect tracking of the truth-value of propositions. What could be more natural?

Yet Williamson's Chapter 7 systematically demonstrates that sensitivity, in every form it's been proposed, either:

• Commits us to radical skepticism, OR
• Requires rejecting the deductive closure of knowledge, OR
• Becomes trivial through infinite regress, OR
• Fails to account for how knowledge actually works

The Skeptical Consequence

Here's the simplest problem. Imagine a good case where everything is as it appears—you're reading at a desk, seeing your hands, the world presents itself normally. And imagine a bad case—you're a brain in a vat, but the simulation is perfect. You can't tell from inside which case you're in.

Now ask: In the good case, do you sensitively believe you're not in the bad case?

Answer: No. Because if you were in the bad case (being perfectly simulated), you would still believe you weren't in it. The simulated scenario is, by hypothesis, indistinguishable from the inside.

Therefore, by sensitivity, you don't know you're not in the bad case, even in the good case where you actually aren't in one.

But wait—you know you're not being systematically deceived. It seems absurd to say you don't know this.

This is the sensitivity dilemma: Accept the intuition that knowledge requires sensitivity, and you must accept that we don't know we're not in skeptical scenarios. Reject skepticism, and you must reject sensitivity.

The Failed Solutions: Methods, Contextualism, Broad Content

Philosophers have tried to rescue sensitivity through increasingly sophisticated moves:

Nozick's Method-Based Approach: Maybe sensitivity only applies via a particular method. If I see the tree by ordinary daylight, and if the tree were not there I would see its absence (different method), then I sensitively know via that method that the tree is there.

Problem: Methods can't be internal (that leads back to skepticism) or finely individuated (that makes the condition trivial). The dilemma remains unsolved.

DeRose's Contextualism: Maybe the truth conditions of "know" shift with conversational context. When skeptical scenarios become salient, we raise our standards, so we can deny knowing we're not in skeptical scenarios when that possibility is under discussion.

Problem: This doesn't solve the core issue—it just relocates it. And it still commits to sensitivity-like requirements in high-standard contexts.

The Broad Content Problem (Most Devastating): Here's where the argument becomes structural: Knowing that P is broad—it depends on external facts. P must actually be true. The content itself couples mind and world.

But if content is broad, then the sensitivity condition for that content is also prime (irreducibly unified with its environment). You can't separate the "internal tracking" from the "external fact" because they're not separable to begin with.

This proves that sensitivity was always asking the wrong question. It assumed you could decompose knowledge into:

• Internal mental state (the tracking mechanism)
• External fact (what's being tracked)

But that decomposition fails. Knowledge is the coupling itself.

Why This Matters Beyond Theory

This chapter reveals something profound about authenticity and consciousness:

Authenticity doesn't require transparency. You don't need perfect self-knowledge or perfect tracking of reality to genuinely know something. The margins enabling that impossibility are constitutive of knowledge itself.

Consciousness works through coupling, not transcendence. You can't abstract yourself from the world and track it from some view-from-nowhere. Your knowledge is always already embedded in your actual engagement with what you know.

The boundaries aren't defects—they're features. Earlier chapters (4-5) established that margins for error structure all knowledge. This chapter proves why: because knowledge is prime. Irreducibly relational. You can't optimize it away.

The Architecture Revealed

Williamson's refutation of sensitivity establishes a complete architecture:

1. Knowing is prime (Ch 3) – can't be decomposed into internal components + external facts
2. This means knowing requires margins (Ch 4-5) – you can't track perfectly because tracking assumes a decomposition that doesn't exist
3. Therefore sensitivity is the wrong requirement (Ch 7) – it's based on a false picture of how mind and world relate
4. What remains is safety – you could not easily have been wrong in a similar case

This explains why authentic engagement happens within your actual bounds, not through transcending them. You don't know by achieving perfect clarity. You know by being reliably coupled with how things actually are.

Ready for Skepticism?

You might think: "If sensitivity fails, haven't we embraced skepticism?"

Quite the opposite. We've escaped the skeptical spiral entirely. Skepticism arose from demanding an impossible condition—that you track reality independently of your actual engagement with it. Once you recognize that demand was incoherent, skepticism loses its grip.

You know you're not in a vat. Not because you can rule it out with certainty. But because your actual engagement with the world—your methods, your senses, your reasoning—are coupled with how things really are. And that coupling is constitutive of knowing itself.

What Comes Next

Chapter 8 turns to skepticism directly, armed with this architecture. With sensitivity refuted and margins established as foundational, Williamson can show why skepticism's traditional arguments fail at a structural level.

The margins aren't where skepticism lives. They're where authentic knowledge lives.

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Synthesis: Chapter 7 proves that sensitivity—perfect counterfactual tracking—fails in every proposed form because it rests on a false decomposition of mind and world. Knowledge is prime: irreducibly coupled with its actual environment. Authentic knowing works within the margins, not through transcending them. This chapter transforms understanding of consciousness, authenticity, and the relationship between mind and reality.