It is fascinating and inspiring to study the history of science. It is also remarkable how it is simply impossible for humans to not always be primarily driven by their humanness. Sometimes this is incredibly useful, because it brings insights of the highest order; sometimes it is painfully debilitating, because it prevents seeing the obvious due to an intellectual stance that rejects an idea based on already acquired and strongly held notions.
To muddle the situation further, our humanness leads us to, over time, remember things in a way that suits us better right now, such that the same sequence of events are remembered and then interpreted differently depending on the circumstances, the mindset, and the knowledge as well as opinions we hold and have acquired since these events took place.
I am currently reading The Cambridge Companion to Einstein, a collection of fourteen essays by leading historians and philosophers of science that introduces his work in the historical and philosophical context in which it took shape and arose. There are a few essays that discuss the photoelectric effect, the insight for which Einstein received his only Nobel prize. This work of one of the most important in the history of modern physics because it was the foundation of quantum theory. The fifth essay in the collection, The Experimental Challenge of Light Quanta, is by Roger Stuewer.
Many experimentalists ran many experiments to test Einstein’s theory that light was in fact quanta, little bundles of energy, whose energy depended only the frequency of the light with Plank’s constant as the proportionality constant: E = hv. But surely it was Robert Millikan’s famous oil drop experiment that demonstrated beyond debate that all of Einstein’s predictions were in accordance with experimental reality. Nevertheless, at the time, Millikan himself would not believe it. He wrote in 1917, reflecting on his experimental testing of Einstein’s quantum theory of light that culminated in 1915:
Despite … the apparently complete success of the Einstein equation, the physical theory of which it was designed to be the symbolic expression if found so untenable that Einstein himself, I believe [my italics], no longer holds to it, and we are in the position of having build a very perfect structure and then knocked out entirely the underpinning without causing the building to fall. It [Einstein’s equation] stands complete and apparently well tested, but without any visible means of support. These supports must obviously exist, and the most fascinating problem of modern physics is to find them. Experiment has outrun theory, or, better, guided by erroneous theory [Stuewer’s italics], it has discovered relationships which seem to be of the greatest interest and importance, but the reasons for them are as yet not at all understood.
But 33 years later, in his 1950 autobiography, he recalled, in a chapter entitled The Experimental Proof of the Existence of the Photon, that at the meeting of the American Physical Society (APS) in April 1915 he presented “my complete verification of the validity of the Einstein equation” and then added:
This seemed to me, as it did to many others, a matter of very great importance, for it … proved simply and irrefutably I thought, that the emitted electron that escapes with the energy hv gets that energy by the direct transfer of hv units of energy from the light to the electron [Millikan’s italics] and hence scarcely permits of an other interpretation than that which Einstein had originally suggested, namely that of the semi-corposcular or photon theory of light itself.
What does this mean, and what does it tell us about not just Millikan, but about ourselves? It shows us that the opinions, beliefs, ideas, notions that we hold of how things are will generally force us into a mindset that brings us to reject the obvious even in the face of “irrefutable” experimental evidence simply because we are not ready to accept it. And it shows us that generally, each time we will recall something, each time we will bring something back from the annals of our memory, it will be reshaped by the mindset that we currently hold, which in turn is continuously reshaped and sculpted by information, acquired knowledge, and experiences we are presented with as we go about our daily lives. This is certainly one of the hallmarks of our humanness; a hallmark of our being humans. Is it wrong to distort history in this way? Who’s to say. Do we all do it? Maybe.