I. Why the Less Someone Knows, the More They Seem to Know Everything

You have certainly met this kind of person:

He has opinions on everything, unshakeable certainty about everything, delivers conclusions the moment he opens his mouth, and never says "I'm not sure" or "I don't know about this." Whatever you ask him, he can give you a definitive, iron-clad answer on the spot.

And yet — these are often exactly the people who know the least.

On the other hand, the genuine experts around you — the ones who actually know a great deal — tend to say things like "it depends," "I'm not entirely certain," "I might be wrong." The more someone knows, the less willing they are to make sweeping claims.

Why do the people who know the most sound the least certain, while the people who know the least are the most self-assured?

In Chapter 71 of the Daodejing, Laozi gets to the bottom of this with a single sentence.

II. "Knowing That You Don't Know — That Is the Highest"

Laozi says:

"Knowing that one does not know — that is the highest."

First: read this sentence correctly. "Knowing that one does not know" is not about whether you understand something. It means: you know what you don't know — you are clear about where your boundaries lie.

This is not the kind of "knowing" that comes from having read many books. A person can have read extensively and know a great deal, yet have no idea where their limits are. What Laozi means by "knowing that one does not know" is a different kind of knowing — a clarity about oneself: I know what I understand, and more importantly, I know what I don't understand.

An analogy: a useful map is not just one that marks what is known — it is one that honestly marks "unexplored territory" where it exists. A map that pretends to be complete, with no blank spaces, is the most dangerous kind: you follow it and step right into the unmarked void. The same is true of a person's knowledge: knowing where the blank spaces are is far more reliable than pretending they don't exist.

Laozi says elsewhere (ch. 33): "Knowing oneself is enlightenment." "Knowing that one does not know" is the most essential half of this self-knowledge: knowing your own "not-knowing."

Why is this "the highest"?

Because once you are clear about your boundaries, you know where to stop, where to ask another question, where to be especially careful. Knowing your boundaries means knowing where the doors are — and having a chance to step through them. The person who doesn't know their boundaries just keeps running into invisible walls. Knowing your own limits is what keeps you grounded and lets you keep growing.

III. "Not Knowing That You Don't Know — That's Trouble"

Laozi immediately gives the opposite:

"Not knowing that one does not know — that leads somewhere bad."

The word here, usually translated as "illness," means something closer to "going in a bad direction" — it is not about sickness.

"Not knowing that one does not know" means: you don't know what you don't know — you simply cannot see your own blind spots.

There is a significant textual difference here. The Mawangdui silk manuscript (帛书) reads "not knowing that one does not know"; the received text (通行本, the most widely circulated version) changed this to "not knowing but thinking one knows" — not knowing something yet pretending that you do.

These two phrases point at two different people:

— The received text's version: knowing you don't understand but performing understanding anyway (a kind of bluffing).

— The silk manuscript's version: having no awareness at all that you don't understand (you don't even know that you don't know).

The silk manuscript's reading is both deeper and more common. The bluffer at least knows inside that he doesn't understand; the person who "doesn't know that he doesn't know" cannot see their own blind spot at all — they dive in with full confidence into something they cannot see clearly. And most serious mistakes happen exactly here: in the "I had no idea I didn't know that" zone.

Today, this has a famous name: the Dunning-Kruger effect.

Simply put: the less someone knows about something, the less able they are to see how little they know — and so their confidence is highest.

The mechanism is a cruel irony: the ability to judge "how well do I understand this" is itself a skill — and it requires roughly the same competence as actually understanding the thing. So the more of an outsider you are, the more you lack the very skill needed to see how much of an outsider you are. The most ignorant person ends up thinking they understand everything. Ignorance hides itself — it keeps you from even seeing the fact that you are ignorant.

You have probably seen this: someone three months into a field who feels qualified to pronounce on the entire industry; while a twenty-year veteran, asked the same question, frowns and says: "It's complicated — it depends on several things." The newcomer isn't smarter. They just haven't walked far enough to see how complicated things are.

This is the answer to the puzzle at the opening: the people who know the least lack precisely the ability to see how little they know — so they are the most certain. The people who know the most can see clearly the vast ocean beyond their own edge — so they are the most humble.

The hardest part is that this mirror is very difficult to hold up to yourself. You can spot someone else's "not knowing that they don't know" instantly; but your own blind spots — precisely because they are blind spots — are invisible to you. The real practice is not in laughing at the person who knows everything — it is in constantly asking yourself: am I, right now, standing in a blind spot I can't see?

IV. Two Thousand Years Ago, Two People on Opposite Ends of the Earth Said the Same Thing

Interestingly, at almost exactly the same time Laozi was saying this, on the other side of the earth, someone else said almost exactly the same thing.

That person was Socrates. His saying, transmitted for over two thousand years, goes:

"The only thing I know is that I know nothing."

That is "knowing that one does not know — that is the highest," is it not?

Two people, separated by half the globe, working in two entirely different traditions, with no knowledge of each other, arrived at the same statement: knowing that you don't know is the highest wisdom.

Why would two completely unrelated people each arrive at the same thing independently?

Because this is not the special claim of any one culture — it is simply true. Laozi in the East, Socrates in the West; one says "knowing that one does not know — that is the highest," the other says "the only thing I know is that I know nothing" — two rivers that never met, flowing to the same sea. Some truths are like this: they don't belong to anyone — they simply are.

V. How the Sage Avoids This Pit: By Treating the Pit as a Pit

So how does one avoid falling into the pit of "not knowing that one does not know"? Laozi gives the answer:

"Therefore the sage does not go in a bad direction, because he treats the bad direction as the bad direction — and therefore he does not go there."

The key phrase here, which I am rendering as "treating the bad direction as the bad direction," literally says "disease-ing the disease" (bìng bìng): the first character means "to recognize as dangerous"; the second is the danger itself. Together: to clearly see the pit for what it is — to know how it swallows people.

The sage avoids this pit not because he is naturally smarter than others, and not because he has no blind spots — but because he treats "thinking you already understand" as a genuinely dangerous pit, and is always on guard against it.

This is the key: the sage doesn't "have no blind spots" — he "knows he must have blind spots." Because he assumes he must have places he cannot see, he keeps asking himself: Am I missing something here? Could I be wrong? Do I actually understand this as well as I think?

This alertness — "I might have a blind spot" — is what it means to treat the pit as a pit.

In other words: the difference between an ordinary person and a master is often not "who has fewer blind spots" but "who is willing to admit they have blind spots and keep looking at them." A person who assumes they won't be wrong — when they are wrong, they get caught completely off guard. A person who always assumes they might be wrong — they have left margin everywhere, they are always checking — and so they rarely make catastrophic mistakes. Humility is not a posture; it is a higher and safer way of operating.

Practically speaking: make it a small habit — whenever you feel "I am especially certain about this," ask yourself one more question: "If I'm wrong, where would the error be?" That one question can often pull you back from the edge of the "not knowing that one does not know" pit.

In my years in Silicon Valley, the most trustworthy engineers and genuine experts I have known — they are exactly the ones quickest to say "I don't know, let me look into it." Not because they lack competence — quite the opposite: because they are clear about their own limits, they are the ones you can most trust. The person who always has a definitive answer and never says "I'm not sure" — that's who you should watch carefully.

When facing genuinely complex things, "I'm not certain" is never a sign of incompetence — it is a sign of professionalism.

VI. To the Reader

This chapter offers several things you can put to use right now:

First: knowing you don't know something matters more than knowing a lot of things.

Real skill is not "knowing everything" — it is being clear about where your boundaries are (knowing that one does not know — that is the highest). Saying "I don't know this" is not embarrassing; it is lucid.

Second: be most on guard about the things you feel most certain about.

The more certain you feel, the more likely that is exactly where your blind spot is hiding (not knowing that one does not know — that leads somewhere bad). The truly dangerous thing is never what you know you don't understand — it is what you think you understand but actually don't.

Third: say "I'm not certain" and "I might be wrong" more often.

This is not weakness — it is clarity. It is also proof that you are still learning and still growing. Always leave room for "I might be wrong."

Fourth: take "I must have blind spots" as a default setting.

The true master doesn't have no blind spots — they know they must have them and actively look for them (treating the pit as a pit). Assuming you will be wrong is what makes you less likely to be seriously wrong.

Fifth: when you meet someone who is certain about everything, keep your guard up.

The person who keeps saying "it depends" and "let me think more" is usually the one who genuinely knows.

This chapter's core can be summed in one line —

True mastery is not in how much you know — it is in whether you know what you "don't know." And always leave a seat at the table for "I might be wrong."