When Silence Becomes Evidence

 

There is an incident from many years ago that I have never forgotten.

An undergraduate student from Electrical Engineering wanted to do his final-year project with me. During one summer, he went to Japan for an internship at a prestigious neuroscience institute. He worked there with a well-known researcher in the field of the hippocampus and spatial navigation.

When he returned, he was full of enthusiasm about what he had learnt.

During one of our discussions, I told him that spatial navigation should not be thought of as something driven solely by the hippocampus. The hippocampus is of course central to spatial cognition, but navigation involves cooperation between multiple systems. The basal ganglia, particularly the striatal system, also play an important role. Different systems support different kinds of navigation strategies, and they interact.

He disagreed.

There was nothing unusual about that. A student should disagree with his teacher when he has reason to. That is how science should work.

So I asked him what his counterargument was.

His answer stunned me.

He said, almost literally:

“This person at Yale and this person in Japan do not think so. They never said that.”

I still remember my reaction.

What exactly was the argument here?

It was not that he had come across an experiment contradicting what I was saying.

It was not that he had found evidence showing that the basal ganglia had no role in spatial navigation.

It was not even that the two famous researchers had explicitly argued against such a role.

They had simply not said it.

And somehow their not saying it had become evidence.

That was the part I found extraordinary.

I had spent decades working on the basal ganglia, reinforcement learning and related problems. I had spent many hours with this student in careful discussion. Yet my claim carried little initial weight in his mind.

By contrast, a casual reading of work from Yale and a two-month internship in Japan had apparently been enough to settle the matter.

The asymmetry was remarkable.

Their silence counted.

My explicit argument did not.

So I did what one should do in science. I went back to the evidence.

I spent hours with him going through experiments by Packard, Knowlton and others on multiple memory systems. We discussed studies showing that animals can solve navigation problems using different strategies, and that hippocampal and striatal systems make distinct but interacting contributions.

Experiment by experiment, the picture became harder to dismiss.

The episode stayed with me because it exposed something deeper than one student's misunderstanding of neuroscience.

It revealed how authority is assigned.

Students, of course, cannot independently verify every claim they encounter. None of us can. We all use reputation as a shortcut. If a scientist has done outstanding work for decades, it is reasonable to give his or her statements greater initial credibility.

Prestige can be a useful prior.

But a prior is not a verdict.

The danger begins when institutional prestige replaces scientific reasoning.

“This person at Yale says so” becomes “this is what neuroscience says.”

“This famous person in Japan never mentioned it” becomes “there is probably nothing important there.”

At that point, authority has quietly displaced evidence.

There was another layer to the incident that bothered me even more.

The student had not merely assigned greater authority to experienced scientists. That would have been understandable.

He had assigned greater authority to distant scientists than to a scientist available to him in his own institution.

This is a pattern I have seen repeatedly in India.

Knowledge from certain places arrives pre-certified.

A statement from Yale, MIT, Stanford, Oxford, Cambridge or a prestigious Japanese institute is granted a high initial value.

A statement made locally may have to prove itself from the ground up.

There seems to be an epistemic exchange rate.

The same intellectual currency is valued differently depending on where it is issued.

This is not an argument that Indian students should defer to Indian professors.

Quite the opposite.

I would have been delighted if the student had said:

“I disagree because experiment X shows the opposite.”

That would have been a scientific argument.

The problem was precisely that he was not arguing scientifically.

He was arguing from authority.

And more strikingly, from omission.

“These famous people did not say it.”

That sentence reveals an entire hierarchy of knowledge.

It assumes that if an idea were important, the recognised centres of knowledge production would surely have articulated it.

If they have not, the idea becomes suspect.

That is a profound form of intellectual dependence.

The problem is no longer merely that we admire foreign institutions.

It is that we may unconsciously grant them the authority to define what questions are important, what explanations are legitimate, and even what facts deserve to exist.

Once that happens, researchers outside those recognised centres do not merely have to produce evidence.

They have to overcome an additional burden.

They must first establish their right to be heard.

That burden is especially visible when the person making the argument is close to us.

A professor in one's own department is familiar.

He is seen walking in the corridor, attending meetings, teaching classes, perhaps struggling with administrative forms.

The scientist abroad is encountered through papers, institutional websites, conference talks and reputation.

One appears ordinary.

The other appears canonical.

Distance creates authority.

And familiarity discounts it.

What disturbed me in that old conversation, therefore, was not that a student disagreed with me.

It was that the burden of proof was distributed so unequally.

The famous scientist abroad did not have to make the argument.

He merely had to exist.

The local scientist had to reconstruct the entire argument from experimental evidence.

That is a serious problem for any society that wants to develop an independent intellectual culture.

Science cannot function by reversing the hierarchy and declaring local authority superior.

That would be equally foolish.

The only durable solution is to restore the proper hierarchy:

Evidence first.

Reasoning next.

Reputation after that.

Prestige may tell us whom to listen to.

It should never tell us what to believe.

That student taught me something I have remembered ever since.

Sometimes intellectual dependence reveals itself not in what we believe, but in whose silence we are willing to treat as evidence.