People Who Want DNA to Prove They Are “Pure Japanese”—Why I Lost Interest in a Story Dressed Up as Science

A Video About the Origins of the Japanese People

The other day, I came across a YouTube video about using the latest DNA analysis to explore the origins of the Japanese people.

This is exactly the kind of subject I usually enjoy.

How much did the Jomon and Yayoi peoples mix? When did people first arrive in the Japanese archipelago, and where did they come from? DNA analysis of ancient human remains has advanced in recent years, giving us a picture of Japanese origins that differs from what we were once taught.

It sounded fascinating, so I started watching.

Partway through, however, something began to feel off.

I found myself wondering: “Is this really an investigation into the roots of the Japanese people, or was the conclusion decided from the beginning?”

The video seemed determined to steer the discussion toward the idea that the Japanese are a highly distinctive ethnic group, separate from people who came from the Asian continent or the Korean Peninsula.

At that point, I lost interest completely.

Science Stops Being Science When the Answer Comes First

There is nothing wrong with proposing the hypothesis that the Japanese population may have genetic characteristics that differ from those of other East Asian populations. It is a hypothesis. We can investigate it.

The problem begins when the starting point is: “I want the Japanese to be a unique people.”

Once that desire comes first, it becomes easy to highlight convenient studies, ignore inconvenient ones, and interpret ambiguous findings to support a preferred position.

DNA, genomes, academic papers, university professors—no matter how much scientific language is used, the conclusion is still driving the evidence.

I studied physics at university, and I believe one of the most important principles of science is accepting a result even when it contradicts your expectations.

The moment you start forcing the data to fit the answer you want, it is no longer science.

The Same Problem Exists on Both the Right and the Left

This problem is not limited to one side of the political spectrum.

Some people collect data to support the conclusion that the Japanese are a special ethnic group. Others collect data to support the conclusion that ethnicity has no meaning at all.

In both cases, the order is backward.

The story comes first, and the evidence is found afterward.

Science matters precisely because research can force us to change our minds. When ideology comes first, however, the conclusion cannot be changed.

Science then stops being a tool for investigating reality and becomes a decoration that lends authority to an argument.

Why Would Continental Ancestry Be a Problem?

This is the part I understand least.

Suppose DNA analysis were to show that present-day Japanese people have substantial genetic ancestry from people who migrated from the Korean Peninsula or the Chinese mainland in ancient times. What exactly would be troubling about that?

It would not stop me from speaking Japanese.

Japanese culture would not disappear.

It would not change the fact that I was born and raised in Japan.

I find it difficult to understand why the place from which one’s ancestors arrived thousands of years ago should threaten one’s identity today.

Ancient Migrants Were Not Modern Nationalities

It is also strange to translate ancient human migration directly into modern nationality.

People hear that migrants came from the Korean Peninsula and conclude that the ancestors of the Japanese must have been Korean.

But the modern nation of South Korea did not exist thousands of years ago. Nor were people arriving from the Chinese mainland “Chinese” in the modern national sense.

Projecting present-day relations among Japan, China, and Korea directly onto ancient history makes little sense.

People at the time searched for food and land. They traded, fought, migrated, and mixed with other groups. Human history is largely a repetition of those processes.

A Complete Lack of Mixing Would Be More Surprising

Japan is not an isolated island in the middle of nowhere. The Korean Peninsula is nearby, and the Chinese mainland lies beyond it.

Japanese culture itself has absorbed enormous influence from the continent, including Chinese characters, Buddhism, the ritsuryo legal and administrative system, rice cultivation, and metalworking.

So much culture crossed the sea. The claim that people somehow remained almost entirely separate for thousands of years seems less plausible to me.

If DNA research reveals that populations mixed in ways that were even more complex than we thought, that would be fascinating. If it shows that the Japanese population is more genetically distinctive than expected, that would be fascinating too.

Either answer is fine.

When Ideology Dresses Itself as Science

I do not think videos expressing nationalist views should be prohibited. People are free to discuss their beliefs.

But they should say clearly what they are doing.

Instead of presenting a video as “Exploring Japanese Origins Through the Latest DNA Research,” call it “My Thoughts on Japanese Identity, Using DNA Research as a Starting Point.” At least then the purpose is clear.

What bothers me is not simply the ideology. It is ideology entering the room dressed as science.

The appeal of science is that we do not know the answer until we investigate.

Perhaps the Japanese population is more distinctive than we imagined. That is fine.

Perhaps it is far more mixed with populations from the continent than we imagined. That is also fine.

But if we have already decided what we want the Japanese to be, there is no reason to study the DNA at all.

The desired answer was there from the very beginning.