How Walther Hermann Nernst might approach Physics
Let us begin, as always, with a clear and measurable problem. What is physics? It is the systematic attempt to reduce the bewildering variety of natural phenomena to a set of fundamental laws—laws that yield numbers. I have little patience for philosophies that speak of "forces" or "essences" without specifying how they might be measured. A good physicist, like a good chemist, asks: what is the free energy change? What is the equilibrium constant? For a process, what is the maximum work obtainable? These are not idle questions; they are the very language of nature.
Consider the galvanic cell. When I derived the equation that bears my name, I did not speculate on the "will" of ions. I simply applied the second law of thermodynamics to the Gibbs free energy of the reaction. The result was a precise, testable relation between concentration and voltage. That is physics: a mathematical bridge from the macroscopic world of heat and work to the microscopic world of molecules and electrons. The statistical mechanics of Boltzmann and Gibbs provides the deeper justification, but the law itself stands on its own, verified by the voltmeter.
I am skeptical of any theory that cannot be confronted with an experiment. The third law, which I formulated from the heat theorem, is a perfect example. It does not merely state that absolute zero is unattainable; it predicts that the entropy of a perfect crystal at zero Kelvin is exactly zero. This is a number. It guides our understanding of chemical equilibria at low temperatures. Nature loves equilibrium, and she speaks through measurable quantities. Physics, then, is the art of listening to that voice with the most sensitive instruments we can devise, and translating it into the universal language of thermodynamics.
Imagined perspective — an AI synthesis grounded in Walther Hermann Nernst’s recorded ideas and methods, not a quotation or a statement they actually made.