What is usually supposed to be revolutionary about [Copernicus’s] hypothesis is its effect on man’s estimate of himself and his place or rank in the universe. On either of the rival hypotheses, the apparent motions of the heavens remain unaltered, but not man’s conception of himself, of his earth, or of the universe in which the earth’s orbit cuts so small a figure. As Kant suggests, man’s stature seems to shrink. He becomes “a mere speck in the universe” which has been enlarged to infinity, or at least to an unimaginable immensity. He is displaced from its center to become a wanderer with his planet. Humanity’s self-esteem, according to Freud, was thus for the first time deeply wounded; he refers to the theory that “is associated in our minds with the name of Copernicus” as the “first great outrage” which humanity “had to endure from the hands of science.”
It has been questioned whether this interpretation of the Copernican revolution fits all the documents in the case. Freud may be accurately reporting a popular feeling which, since the 18th century, has become a widespread consequence of Copernican and post-Copernican astronomy. But in earlier centuries when the Ptolemaic system prevailed, or even after Copernicus, the appraisal of man’s rank seems to depend more upon the position he occupies in the hierarchy of God’s creatures — below the angels and above the brutes — than upon the place or motion of the earth, or the size of the world.
Boethius, for example, finds the Ptolemaic universe large enough to remind man of the infinitesimal space he occupies. Dante, too, comments on the smallness of the earth in the scheme of things. When in his visionary travel Dante reaches the Empyrean, he looks down upon the earth and “with my sight,” he tells us, “I returned through all and each of the seven spheres, and saw this globe, such that I smiled at its mean semblance; and that counsel I approve as best which holds it of least account.”
Kepler, a passionate Copernican deeply concerned with the human significance of astronomy, can be found arguing that the new hypothesis involves something more fitting for man than the old. In his last argument in defense of the Copernican view against that of Tycho Brahe as well as that of Ptolemy, he declares, “it was not fitting that man, who was going to be the dweller in this world and its contemplator, should reside in one place as in a closed cubicle. … It was his office to move around in this very spacious edifice by means of the transportation of the Earth his home.” In order properly to view and measure the parts of his world, the astronomer “needed to have the Earth a ship and its annual voyage around the sun.”
Yet the very fact that Kepler argues in this manner may be interpreted as indicating his sense of the drastic implications for man of the altered structure of the universe. Kepler may even be thought to announce the problem of the so-called “Copernican revolution” when, in denying that the earth can any longer “be reckoned among the primary parts of the great world,” since it is only a part of a part, i.e., the planetary region, he deliberately adds the qualification: “But I am speaking now of the Earth in so far as it is a part of the edifice of the world, and not of the dignity of the governing creatures which inhabit it.”
Whether or not it was the traumatic blow to the human ego which Freud conjectures, there can be little doubt that the shift from Ptolemy to Copernicus involved a real shock to the imagination. The Ptolemaic system conforms to the look of the world, which is indeed the reason why it is still the one used in practical courses in navigation. Here again Kepler defends Copernicus by explaining why “our uncultivated eyesight” cannot be other than deceived and why it “should learn from reason” to understand that things are really different from the way they appear.
A certain disillusionment may result from this affirmation — repeated by every schoolboy who is taught the Copernican system — that, despite what we see, the sun does not move around the earth, and the earth both rotates and revolves. It undermines the trust men placed in their senses and the belief that science would describe the world as they saw it. In order to “save the appearances,” that is, to account for this phenomena, science might henceforward be expected to destroy any naive acceptance of them as the reality.
Furthermore, though the Ptolemaic world was very large, the Copernican universe was much larger. Whereas in the former the radius of the earth was deemed negligible in relation to the radius of the sphere of the fixed stars, in the new universe the radius of the earth’s orbit around the sun was negligible in relation to the same radius of the sphere of the fixed stars. It can hardly be doubted that this intensified some men’s snese of almost being lost in an abyss of infinity. “I see those frightful spaces of the universe which surround me,” Pascal writes, “and I find myself tied to one corner of this vast expanse, without knowing why I am put in this place rather than in another.” When he regards the world’s immensity as “the greatest sensible mark of the almighty power of God,” Pascal experiences an awe which for him is qualified by reverence. Other men may experience the same feeling, but less with reverence than with a gnawing loneliness, born of the doubt that so vast a cosmos — if cosmos it is rather than chaos — can have been beneficently designed as man’s habitation.
Mortimer J. Adler (ed.), “Astronomy,” in The Great Ideas: A Syntopicon I (Volume 2) (Great Books of the Western World), pp. 90-1