February 19, 1473 was the date of Nicolaus Copernicus’ birth. The Polish astronomer is best known for the posthumously published book, De Revolutionibus Orbium Coelestium, in which he outlined a heliocentric model of the universe.

So what has all this to do with the history of psychology? According to the “Today in the History of Psychology” website, “a scientific psychology rests on the assumptions generated by the Copernican revolution,” namely, the “promoting [of] objectivity in the study of human affairs.”

Several aspects of this topic are worthy of discussion. Was Copernicus beset by people opposed to “objectivity” with respect to the nature of the physical universe? Was “objectivity” even an idea that concerned Copernicus in particular? Lorraine Daston and Peter Galison argue in their 2007 book, Objectivity, that this concern emerged mainly in the mid-19th century, not the early 16th. Even if we were to imaginatively cast this issue backwards in time, the most significant opponent of Copernican theory, Tycho Brahe, was known for having the most accurate astronomical observations then in existence. This does not sound like a man incapable of what we would call objectivity.

It is often claimed that Copernicus delayed publishing his book until after his death for fear of the reaction of the Church, the implication being that the Catholic establishment opposed “objectivity.” This claim is highly debatable, however. Copernicus was by no means secretive about the content his theory during his lifetime, as we might expect one who worried about religious repercussions to be. Indeed, in 1533, ten years before his death, the theory was outlined in a series of lectures in Rome before the Pope and a number of Cardinals. The only public response, from one of the Cardinals, was to urge Copernicus to publish the theory. Of course, Galileo suffered a different response from the Church, but that was nearly a century later, at the height of the Counter-Reformation.

More broadly, does it remain credible to speak of the scientific revolution — stretching from astronomy to psychology — when it appears that various disciplines became “scientific” (a contested term if there ever was one) at widely different times, and in manifestly different ways? Although it is relatively easy to “connect the dots” from the astronomical revolution of Copernicus, Galileo, and Kepler to Newton’s “revolution” in general mechanics, is there really an important parallel continuity between them and, say, the chemical “revolution” of Lavoisier, Mendeleyev and others between the late-18th and mid-19th centuries? And again, although there is a strong connection between the scientific formation of geology and that of evolutionary theory, is there one between these and the earlier transformations of chemistry or physics? Or between these and cell doctrine in biology?

And so finally we come to “scientific” psychology. It bears a well-known connection to mid-19th century German physiology, but Wundt was notoriously wary of the Darwinian theory of natural selection. It was only with American developments in psychology (especially in the work of James, Hall, Cattell, and Baldwin) that psychology forged an explicit connection with evolutionary theory. And the possible connections between psychology and earlier revolutions in chemistry, physics, etc. are even more obscure.

So perhaps, as a number of historians of science have urged, it is better to speak a series of relatively independent scientific revolutions, each of which, though cognizant of the previous ones, possessed their own motivations and characters, rather than to lump them together into a single, unified movement that stretched across 500 years in time.