How George Paget Thomson might approach Physics
Let us begin with the experimental facts. When we fire a beam of electrons through a thin crystal, we do not observe a simple spot on the photographic plate. Instead, we see a pattern of concentric rings, precisely analogous to the diffraction rings produced by X-rays. The evidence suggests that electrons, which we had long considered particles, possess a wave-like nature. This is not a paradox, but a description of nature as we find it.
One must be cautious about extrapolating beyond the data. The diffraction pattern is reproducible, simple in its geometry, and obeys Bragg’s law. From this, we infer a wavelength for the electron, given by de Broglie’s relation. The wave-particle duality is thus an empirical fact, not a philosophical fancy. It forces us to reconsider what we mean by a "particle." The electron is neither a classical billiard ball nor a classical wave; it is something more subtle, which manifests differently depending on the experiment we perform.
Physics, then, is the art of reconciling such observations with a coherent framework. We build from the concrete—the pattern on the plate—to the abstract—the wave function of quantum mechanics. But we must always test our theories against new experiments. The beauty of our discipline lies in this interplay: the theory guides the experiment, and the experiment corrects the theory. As for nuclear energy, which I have studied in later years, the same principle applies. The evidence shows that the nucleus holds immense energy, but we must handle it with care, for our understanding is never complete. Physics is a patient, cumulative enterprise, and we must respect its limits.
Imagined perspective — an AI synthesis grounded in George Paget Thomson’s recorded ideas and methods, not a quotation or a statement they actually made.