Methods Have Limits

Every way of knowing has a domain where it works and a domain where it doesn’t. This sounds obvious. It isn’t.

People use methods of knowing outside their valid domain all the time, and they don’t notice they’re doing it. A person has a strong feeling about something and treats that feeling as evidence. Someone reads a compelling argument and treats it as proof. A friend says something with confidence and it becomes fact.

None of these are inherently wrong. Feelings, arguments, and trusted people can all point toward truth. But each has limits, and when you don’t know the limits, you end up certain about things you have no right to be certain about.

The Three Basic Categories

For now, let’s keep it simple. There are three basic ways knowledge arrives:

Direct experience. You saw it, heard it, touched it, tasted it, felt it in your own body. This is the gold standard for things that can be directly experienced. But its domain is narrow — limited to what you personally encountered, at the time you encountered it. You experienced the rain. You can’t experience next Tuesday’s weather.

Reasoning. You took evidence and drew a conclusion. You saw smoke and inferred fire. You noticed a pattern over time and generalized. You followed a chain of logic from premises to conclusion. This is powerful but fragile. The evidence might be incomplete. The pattern might not hold. The logic might contain a flaw you can’t see because you’re inside it.

Testimony. Someone told you. A teacher, a parent, a book, the news, a friend, a website, a cultural narrative you absorbed growing up. This is how you know most of what you know. You didn’t personally verify that the earth orbits the sun — someone told you, and you believed them because it fit with other things you’d been told. Most testimony is fine. Some of it is catastrophically wrong.

Where It Goes Wrong

The problems don’t come from using these methods. The problems come from using them outside their domain.

Using direct experience to conclude something about someone else’s inner life: “I can see he’s lying.” No — you can see his behavior. Whether he’s lying is an inference, not a perception. The certainty of perception is being applied to what’s a guess.

Using reasoning to arrive at emotional truth: “I’ve thought about this carefully and I’ve concluded I should be over the breakup by now.” Emotions don’t follow logic. The reasoning might be impeccable and the conclusion still meaningless. This is the right method applied to the wrong domain.

Using testimony for things that require direct experience: “My therapist says I have a fear of intimacy, so I do.” Maybe. But if you’ve never examined your own experience of closeness and what happens inside you when someone gets near — you’re borrowing someone else’s conclusion about your own inner life. The answer might be right, but you haven’t verified it. You’re taking it on authority.

Each of these feels like knowing. They have the texture of certainty. But the certainty is borrowed from a method that doesn’t apply to the question being asked.

The Feeling of Certainty Is Unreliable

This is the hard part. Certainty is a feeling, not a fact. You can feel absolutely certain about something and be completely wrong. You’ve done it before — everyone has. Remembered something vividly that turned out to be inaccurate. Been sure about someone’s motives and discovered you were projecting. Known something was going to happen and it didn’t.

The feeling of certainty tells you that your brain has committed to a conclusion. It doesn’t tell you the conclusion is correct.

So when you feel certain about something, that’s a signal to check, not to stop checking. How do I know this? What method am I using? Is it the right method for this question?

This is a skill you build over time. At first it feels awkward, like interrupting yourself mid-thought. Eventually it becomes automatic — a background filter that catches mismatches before you act on them. The people who develop this skill make fewer catastrophic errors. Not because they’re smarter, but because they know the limits of what they know.

Today’s Practice

Go back to your 5 certainties from yesterday. You already identified the source of each one — experience, reasoning, or testimony.

Now ask a harder question: Is the method appropriate for what I’m claiming to know?

If you know your partner is angry because they slammed a door — that’s an inference from behavior, not a perception of their emotional state. Note the gap.

If you know a political position is correct because you read a convincing article — that’s testimony, and the source needs evaluating. How reliable is it? What’s their bias?

If you know something about yourself because someone once told you and it stuck — that’s testimony about your own experience. Have you verified it directly?

Find at least one mismatch. One place where the method doesn’t quite fit the question. That gap between what you think you know and how you know it — that’s where the most important learning happens.