In the history of physics, Shinichiro Tomonaga occupies the ground between patient observation and the larger claims it makes possible.
Shinichiro Tomonaga was born in 1906. His recorded nationality is Japan.
Around the turn of the twentieth century the sciences fractured into specialisms and simultaneously became national assets, funded and directed on a scale no earlier generation had seen.
In physics the decisive move is usually not the theory but the apparatus built to test it.
Like many of his contemporaries, Shinichiro Tomonaga moved between physics and genetics without regarding the boundaries as real.
The Japan setting is not incidental. National academies, funding and language decided which findings travelled and which stayed local, in this period as in ours.
The measure that matters is durability. Results that survive re-examination become the floor of a discipline, and it is on that floor that everything afterwards is built.
Death came in 1979, at 73. By then the contribution had passed into the settled body of physics, where it is used without being credited - the surest sign that it was right.
