PERSON
Rudolf Clausius
The Prussian physicist who named entropy in 1865 and, without knowing it, wrote the accounting rules that govern every machine ever built from information—giving the artificial minds of the twenty-first century their deepest physical law.
Rudolf Clausius is the man who handed science its two most universal sentences:
the energy of the universe is constant; the entropy of the universe tends to a maximum. Coined to describe steam engines in 1865, the word he invented—deliberately shaped to stand beside
energy, borrowed from the Greek for transformation—traveled from the cylinder to the data center without changing its mathematical form. When Claude Shannon needed a name for the quantity that measures information, he was advised to call it
entropy, because the mathematics was formally identical; when Rolf Landauer proved in 1961 that erasing a single bit of information releases heat, the loop closed completely. The
thermodynamics of computation is Clausius’s accounting applied to thought. The
large language models now reshaping every institution are trained by minimizing cross-entropy—a loss function built directly from Shannon’s quantity, which is built directly from Clausius’s, renamed—and their cooling towers are where the price of that training is paid in heat. He offers