In a book titled Prolegomena to Any Future Metaphysics, Immanuel Kant attempts to rectify the perceived errors of empiricist and rationalist philosophies by developing a new theory of knowledge that can account for the universal laws of math and science without falling into skepticism or resorting to dogmatism. In establishing his new epistemology, Kant draws a comparison between his philosophical innovation and the innovation of Nicolaus Copernicus in the field of Astronomy. However, while Copernicus’ revolution in astronomy shifted the focus of the science away from how the heavens relate to men, and toward how the celestial bodies move in themselves, Kant’s “Copernican Revolution” in philosophy reduces the universal and necessary laws of math and science to operations of the mind, which merely govern the appearances of external things that cannot be known in themselves. Kant’s subjective turn parallels the paradigm shift that occurred in the world of astronomy during and after Copernicus’ life, but these two Copernican Revolutions turn out to be moving in opposite directions.
To understand why Kant would liken his new philosophy to a revolution in the sciences, it is important to first examine astronomy and cosmology, prior to the Copernican Revolution. While today it is almost impossible to conceive of a reasonable cosmology that is wholly extricated from astronomy, this was not the case prior to Copernicus. According to Thomas Kuhn, in The Copernican Revolution, every ancient civilization and culture of which there are records had a cosmology, “an answer for the question, ‘What is the structure of the universe?’”[1] And while it is true that such cosmologies differ substantially from one to the next, it is also undeniable that their origins arose largely from the terrestrial experiences of their authors. Just one example of this is a form of ancient Egyptian cosmology, in which the earth was pictured as an “elongated platter,” which paralleled the Nile river. This platter-world, as Kuhn explains, was bounded by mountains, had a flat bottom, and was covered by a platter-dome. It was the many Egyptian gods who would ensure that the sun, stars, and other features of the natural world could continue to operate as normal. But Kuhn points out that this kind of cosmology was not so far-fetched as a modern mind might think, as “several of the main structural features of this universe were suggested by the world that the Egyptians knew: he did live in an elongated platter bounded by water in the only direction in which he had explored it; the sky… did and does look dome shaped…”[2] Of course, the purpose of these explanations is not the same as that of modern cosmology or astronomy.
For ancient cultures, like that of the ancient Egyptians, cosmology’s aim is different than that of modern science. Instead of attempting to discover and explain the place and purpose of the celestial orbs, or the laws that govern their motions, the cosmologies of most ancient civilizations existed to serve the more religious and philosophical purpose of explaining the place and purpose of man in the universe. Woven into these fantastical explanations of the universe are tales about gods, like the Egyptian sun god Ra, who the Egyptians thought travelled across the heavens in a boat every day, thus accounting for the movement of the sun.[3] However, these cosmological systems never make any attempt to explain the regularity of the travel or the seasonal variations of Ra’s route, as he treks the heavens in his boat. All of these ancient, notably unscientific ideas about the cosmos reveal peoples who desired to know little more about the universe than how it was related to them, as an extension of their terrestrial home.[4] A notable exception to this approach to cosmology is that of Hellenistic Greek culture.
While the Greeks were making advances in philosophy and geometry, they too gazed heavenward, and pondered the mysteries contained in the skies. But their approach was shaped by their philosophy and mathematics. As such, their cosmologies were closer to a modern scientific point of view, in that they allowed their astronomical observations to inform and improve their explanations of the cosmos. And while Ptolemy’s Amalgest, a mathematically thorough accounting of the movements of the stars, eventually became the standard by which all works of astronomy were measured, it is the influence of Aristotle’s works which for so long dissuaded astronomers from pursuing a non-geocentric view of the universe. Until Copernicus, according to Kuhn, astronomy in the West was essentially rooted in cosmological views that were as philosophical as they were observational. Consequently, the majority of later astronomers seeking to amend Ptolemy’s work actually upheld his geocentrism, simply endeavoring to improve Ptolemy’s mathematics, sometimes irrespective of the observable motions of the stars. This, ultimately, led Copernicus to consider something radical: removing the stationary earth from its perch in the center of the universe.[5]
While Copernicus’s De Revolutionibus Orbium Coelestium is often considered to be a revolutionary text, it actually draws heavily from the Ptolemaic tradition of astronomy. In this sense, Copernicus’ work might be more appropriately known as the spark for the Copernican Revolution, but not the revolution itself. As such, his goal for De Revolutionibus was merely to construct a mathematical description of the movements of the stars and planets which coincided with their real, observable movements.[6] But whether he realized it or not, Copernicus severed, or began to sever, astronomy’s reliance on cosmologies that were rooted in man’s subjective philosophical views.[7] And, though his solution to the problem of the planets is flawed, it led to a marriage of observation and mathematics that is all too familiar to the modern scientist. The Copernican Revolution, then, was a shift of perspective, from examining the celestial orbs primarily insofar as they relate to man, to examining the way they move in themselves, independent of man, as a result of the laws of nature. Such a shift in perspective nearly prefigures what would later occur in philosophy.
Just as the real Copernican Revolution was preceded by a long and storied history of astronomy, so too is Kant’s philosophical revolution the culmination of a long philosophical journey. By the time Kant stepped onto the scene, epistemology, the study of man’s understanding, had been one of the primary subjects of philosophical debate for centuries. Beginning with Locke and Descartes, especially, new theories of mind began to present new problems, and ultimately led to the Empiricism-Rationalism split in philosophy, wherein the former emphasized experience, the latter emphasized pure reason, and both strayed far and wide from Scholastic views of human understanding. In short, despite their disagreements on things like innate ideas, or the primacy of experience, both sides of the debate agree on one point, which separates them from the Scholastics: that the object of human understanding is not external things-in-themselves, but ideas. In other words, the Thomistic-Aristotelian notion of knowledge as an extraordinary mode of being, and the supposition that ideas are that by which man knows things-in-themselves, are completely rejected by Locke, Descartes, Hume, and most of their contemporaries. But it is David Hume who recognizes a fatal flaw in this notion, pointing out that to claim ideas as the object of knowledge is to be trapped in a world of illusions, which may or may not correspond with the external reality.[8] Hume also claims that neither the empiricists nor the rationalists can adequately account for causality or substance on the merits of their respective philosophies. So, Kant embarks on a mission to rectify the issues that face Rationalism and Empiricism by reexamining human understanding.[9]
In a world dominated by the advances of modern science, Kant knows that he must formulate a theory of mind that upholds the laws of Newtonian physics as universal and necessary, while also taking into account the criticisms of Hume. The problem, for Kant, is how to find a rational basis for categories like causality, substance, time, and space, all within the structure of an idealist theory of mind. Kant agrees with Hume that a priori reason, which is purely analytic, is not sufficient for arriving at such categories, even though a priori judgements are universal, necessary, and objective.[10] Similarly, Kant accepts Hume’s argument that the grounds for these categories cannot be found in experience, because the objects of experience are nothing more than loose and separate sense data. After accepting these criticisms, Kant sees that in order to rescue Newtonian physics from Humean skepticism, he must radically alter man’s view of what the laws of physics actually govern. Herein lies the foundation of Kant’s Copernican Revolution in philosophy.
In attempting to mend the philosophical damage done by the idealists preceding him, Kant espouses a truly revolutionary view of the mind. Because Kant adheres to a kind of idealism, in which the idea is the object of human knowing, rather than things-in-themselves, he must recast what categories like space and time actually are. Kant explains that space and time are not, in fact, properties of external things-in-themselves. Instead, he argues that such categories are the ways in which sense perceptions are made intelligible to man, and thus are actually the forms of sensible intuitions.[11] In other words, space and time, as experienced by men, reside entirely within the human being’s intellect, like empty containers, whose sole function is to be filled with loose and separate sense perceptions, which they then make intelligible, just as a bowl gives shape to water when filled. This, of course, has far-reaching implications for what the laws of Newtonian Physics actually govern.
If the laws of Newtonian physics are that which govern space and time, as Kant is wont to admit, but space and time are merely the forms of man’s sensible intuitions, then physics, as a field of study, is much different than most modern scientists would admit. In fact, as Kant so strongly states in his Prolegomena to Any Future Metaphysics, “all the properties which constitute the intuition of a body belong merely to its appearance.”[12] So, on Kant’s view, one must admit that the universal and necessary laws of Newtonian physics, while they may or may not correspond with the actions and movements of external things, can only be shown with certainty to be the laws which govern the appearances of things. In this respect, Kant believes he is simply bringing the idealism of his predecessors to its proper logical end, and in so doing, circumvents the issues brought up by David Hume. Kant is quite succinct in expressing all of this, when he says, “the understanding does not derive its laws (a priori) from, but prescribes them to, nature.”[13] Ultimately, this shift in man’s perspective is what characterizes Kant’s Copernican Revolution, in which man’s intellectual connection to the outside world is almost entirely severed, as the mere existence of external objects is their only provable attribute.
While these two Copernican Revolutions parallel one another in some ways, Kant’s turn to the subject is an all-out sprint in the opposite direction of Copernicus’ work. After Copernicus wrote De Revolutionibus, as Thomas S. Kuhn shows, the science of astronomy began to shed its attachments to the subjectivism which had held it in check for so many centuries. This detachment divorced astronomy from certain philosophical and religious constraints that cemented the earth as the center of the universe for reasons that, though not entirely devoid of experience, relied largely upon the assertions of the great minds of the age, who sought to shape the universe as they saw fit. Copernicus sparked the flame that transformed astronomy into a science that is more recognizable today; one mainly concerned with discovering the natural laws which govern external things, through observation and mathematics. Kant, of course, shifts philosophy in the opposite direction. His Transcendental Idealism is a dramatic turn to the subject, where the laws of nature are not inherent to nature, but are instead imposed upon it by the human mind. By making this claim, Kant essentially reduces all sciences to the study of the human understanding, rather than the study of external things, a notion that is quite contrary to the results of Copernicus’ own influence. Ultimately, Kant’s revolution in epistemology is Copernican in kind, but anti-Copernican in effect.
Works Cited
Jones, W.T. 1975. Kant and the Nineteenth Century. Fort Worth: Harcourt Brace Jovanovich College Publishers.
Kant, Immanuel. 1977. Prolegomena to Any Future Metaphysics. Indianapolis, IN: Hackett Publishing Company, Inc.
Kuhn, Thomas S. 1957. The Copernican Revolution. Harvard COllege: President and Fellows of Harvard College.
[1] Thomas S. Kuhn, The Copernican Revolution (Harvard College, 1957), 5
[2] Kuhn, The Copernican Revolution, 5
[3] Kuhn, The Copernican Revolution, 6
[4] Kuhn, The Copernican Revolution, 6
[5] Kuhn, The Copernican Revolution, 64-95
[6] Kuhn, The Copernican Revolution, 140
[7] Kuhn, The Copernican Revolution, 184
[8] W.T. Jones, Kant and the Nineteenth Century, 16
[9] W.T. Jones, Kant and the Nineteenth Century, 16
[10] Immanuel Kant, Prolegomena to Any Future Metaphysics, 3
[11] Immanuel Kant, Prolegomena to Any Future Metaphysics, 24, 28
[12] Immanuel Kant, Prolegomena to Any Future Metaphysics, 30
[13] Immanuel Kant, Prolegomena to Any Future Metaphysics, 58
Moths, Flames, and Philosophy 