Borrowed Certainty

How much of what we know did we actually learn for ourselves?

Most of us carry around an astonishing number of things we believe to be true.

We know which foods are healthy. We know why the economy is doing what it’s doing. We know what happened in history. We know which institutions can be trusted. We know why a public figure made a particular decision. We know what kind of person someone is.

At least, we say we know.

But if someone stopped us and asked a slightly different question—

How do you know?

—the answer might be more complicated.

Because much of what we call knowledge isn’t knowledge we acquired ourselves.

It is certainty we borrowed from someone else.

We couldn’t live any other way

This isn’t a flaw.

No human being has enough time to independently verify everything necessary to live.

I have never personally tested whether the structural calculations used to build every bridge I cross are correct. I haven’t inspected the factories that manufacture the medicine in my cabinet. I haven’t replicated the scientific experiments behind most of what I learned in school.

Neither have you.

We rely on other people.

Experts. Institutions. Teachers. Journalists. Historians. Doctors. Engineers. Friends. Parents.

Civilization depends on this.

Trust allows knowledge to accumulate across generations. One person doesn’t have to rediscover everything another person already learned.

That’s an extraordinary human achievement.

But it creates an interesting problem.

Eventually, information can become separated from the reason we trusted it in the first place.

We remember the conclusion.

We forget the chain that produced it.

The disappearing source

Think about something you’ve believed for years.

Not something controversial. Something ordinary.

Perhaps a story about your hometown. A piece of family history. Something you learned about a famous person. A fact you’ve repeated in conversation.

Now try to remember where you first learned it.

Sometimes that’s easy.

Often it isn’t.

You simply know it.

But at some point, that knowledge entered your mind from somewhere.

Someone told you.

You read it.

You saw it on television.

A teacher mentioned it.

Your parents believed it.

Everyone around you seemed to know it.

The source disappeared.

The certainty remained.

That transformation fascinates me.

Because once the source is gone, we can no longer evaluate it.

We aren’t remembering that someone once told us something.

We’re remembering the thing itself.

Certainty can travel

Imagine someone tells you a story about a person you’ve never met.

They heard it from someone they trust.

You trust them.

Later, the subject comes up with another friend and you repeat the story.

You don’t say, “Someone I trust heard from someone else that…”

You probably just tell the story.

Now your friend possesses it.

Perhaps your friend repeats it too.

After enough transfers, something peculiar happens.

Everyone knows the story.

Almost nobody knows the source.

Yet repetition may actually make the story feel more credible.

We’ve heard it before.

Other people have heard it too.

There seems to be agreement.

But ten people repeating the same claim aren’t necessarily ten sources.

They may be one source with nine echoes.

We inherit confidence along with information

This is where borrowed certainty becomes especially interesting.

When someone gives us information, they often give us their level of confidence with it.

A parent doesn’t say:

“My current interpretation, based on incomplete information, is that Uncle Henry made a terrible financial decision in 1987.”

They say:

“Uncle Henry was terrible with money.”

A child hears that sentence differently.

There is no uncertainty to evaluate.

It’s simply part of the world.

Years later, the child may repeat it with exactly the same confidence despite possessing none of the original information.

The conclusion survived.

The evidence did not.

Families do this.

Organizations do it.

Communities do it.

Entire cultures do it.

We inherit not only stories but the confidence attached to them.

Authority makes borrowing easier

Some sources naturally carry more weight.

A title.

A uniform.

A prestigious institution.

A respected publication.

A person with decades of experience.

Often that weight is deserved.

Expertise matters.

But authority can create a subtle shortcut in our thinking.

Instead of asking whether the evidence supports the claim, we ask whether the person making the claim is someone who would know.

Usually that’s efficient.

Sometimes it’s dangerous.

Because expertise in one area doesn’t create expertise in another. Institutions can make mistakes. Authorities can possess incomplete information. Highly intelligent people can become attached to explanations just like everyone else.

And sometimes the confident person at the microphone is simply repeating certainty borrowed from someone farther up the chain.

Authority can validate knowledge.

It can also disguise how far that knowledge has traveled.

The internet accelerated the transfer

We now encounter more claims in a day than previous generations might have encountered in weeks.

Headlines. Posts. Videos. Charts. Screenshots. Commentary. Clips.

Most arrive already interpreted.

Someone isn’t merely showing us what happened.

They’re telling us what it means.

Then someone else reacts to that interpretation.

Another person summarizes the reaction.

Someone screenshots the summary.

By the time the information reaches us, we may be several layers removed from the original event.

Yet the final version can arrive with enormous confidence.

Sometimes more confidence than existed at the beginning.

That’s worth noticing.

Information can become less certain as it travels.

Its presentation can become more certain.

Skepticism has the same problem

There’s an easy trap here.

Once we realize how much certainty is borrowed, we can begin distrusting everything.

That isn’t much better.

Automatic disbelief is still automatic.

A person who rejects every institutional explanation isn’t necessarily thinking more critically than someone who accepts every one.

Both may simply have chosen different authorities.

One borrows certainty from the institution.

The other borrows certainty from the person saying the institution is lying.

The underlying habit hasn’t changed.

Only the source has.

Real skepticism seems harder.

It requires being willing to say:

I don’t know yet.

That sentence doesn’t travel particularly well.

But it may be one of the most intellectually honest sentences available to us.

Following the chain backward

Perhaps the useful question isn’t whether we should trust people.

We have to.

The better question may be whether we know what kind of knowledge we’re holding.

Did I see this myself?

Did someone tell me?

Do I know the original source?

Am I relying on expertise?

Am I relying on consensus?

Am I repeating something because I’ve heard it many times?

None of those automatically makes a belief wrong.

They simply describe different relationships to evidence.

And knowing the difference matters.

Because there is a substantial difference between:

I know.

I have good reason to believe.

and

Someone I trust seems certain.

In ordinary conversation, we often treat those statements as interchangeable.

They aren’t.

Most of us will spend our lives depending on knowledge acquired from other people.

That’s not weakness.

It’s how human knowledge works.

But perhaps occasionally we should trace one of our certainties backward.

Past the person who told us.

Past the person who told them.

Back toward whatever evidence existed at the beginning.

We may discover that what we believe is well supported.

We may discover that it isn’t.

Or we may discover something even more interesting.

We don’t actually know why we’re certain.

We just know that someone else was.

— Thomas