Recently, I was involved in a thread on a Catholic blog that asked whether quantum mechanics could be reconciled with scholastic theology. I answered in the negative, since I believe that the Catholic church’s refusal to junk its back door Aristotelianism (i.e., Thomism) as well as its nineteenth century refusal to consider that non-scholastic philosophy might form the basis of its theology doesn’t bode well for the would-be quantum Catholic. In particular, I emphasized how Aristotelian physics is embedded into Catholic theology to the point where it really can’t be taken out without causing major problems. Of course, I was accused of confusing physics with metaphysics, but I stand by my point.
When Thomas Aquinas wrote his Summa, he was acting under the assumption that Aristotelian physics were an accurate description of how the universe works. For more information on Aristotelian physics, please examine the following links:
When Aquinas brought up “accidents” and “essences,” for example, he was not just talking about metaphysical ideas, but thought he was describing what he believes to be the building blocks of the physical world. Under Thomism, the essence and existence of a thing are necessary for it to be. However, there is no room in this model for an atomic theory, much less a quantum theory, and there is no empirical evidence that any of his concepts exist anywhere outside of the philosophical system he created. It doesn’t matter how internally consistent Thomism or original flavor Aristotelianism is, because at the end of the day neither system describes empirical reality.
Not only was Aquinas’ world governed by Aristotelian physics, it was also very small and geocentric. Think of the universe Dante describes in his works (Inferno, Purgatorio, and Paradiso):
Notice that the map shows the Earth as the center of the universe, which is in turn surrounded by the concentric spheres containing the moon, the sun, each of the known planets, the “fixed stars,” and finally God. Contrary to what many people believe, the Earth was at the center of this cosmological model not because of an anthropocentric conceit that humans were the most important thing in the universe, but because of the Platonic view that what was evil was closest to the ground (i.e., Hell), whereas the farther one went from the ground the more holy and pure things become (i.e., Heaven). Since the celestial realm was believed to be perfect and unchanging, it was only fitting that the heavenly bodies move in uniform circular motion. It’s a remarkable synthesis of medieval Christian theology and classical thought, and it’s all completely wrong.
One reason why the Ptolemaic/Aristotelian cosmological model lasted so long is because the church invested a great deal of theological significance in it. If nothing else, the princes of the church were loath to junk a model that had not insignificant amount of scriptural basis behind it. While the Bible does not explicitly state that the sun revolves around the Earth, it definitely says that the Earth is in a fixed position and doesn’t move (see Psalm 93:1, 1 Chronicles 16:30, Job 9:6), while the sun is mobile (see Job 9:7, Psalm 19:4-6). The miracle of Joshua stopping the sun is accomplished because the sun moves, but not the Earth. Today the references to the Earth being stationary are explained away as metaphors, but for most of Christendom they were taken to be an accurate description of the way things were. It’s not hard to see why a geocentric model made theological as well as common sense, since pre-modern people had no reason to believe that the Earth moved.
When the Galileo affair is discussed, people tend to harp on the clash between the heliocentric and geocentric models, but I think this is the wrong view to take, especially since Galileo’s own cosmological model retains most of the incorrect assumptions of the Ptolemaic/Aristotelian system, such as circular orbits, equants/epicycles/deferents, and a tiny universe. To me, the aspect of Galileo’s work that was really revolutionary was that he was the first to build a telescope at point it at the sky. Despite the crudity of his device, Galileo was able to see with his own eyes phenomena that cast serious doubt on Aristotelian physics, such as some of the moons of Jupiter (Aristotle says everything is supposed to move around the Earth, so no other body should have satellites), sun spots (evidence of the non-perfection of the “celestial spheres”), and the phases of Venus (a geocentric model has no way of explaining how this can occur). The magnificent rings of Saturn also posed a problem Galileo, especially since they appeared to be moons or “arms” that would disappear and reappear. There was nothing in the Ptolemaic/Aristotelian model that could explain Saturn’s “arms,” and it wasn’t until Christiaan Huygens looked at Saturn through his own, more powerful telescope that he was able to discover the ring, as well as one of Saturn’s moons, Titan. In retrospect, the fact that the Ptolemaic/Aristotelian model got the position of the sun and the Earth wrong is the least of its problems.
Scholasticism could be reconciled with quantum physics, but only if certain aspects of the former are changed or ignored. Aquinas’ writings are full of incorrect speculations about how the natural world works, assumptions that are in turn used to justify his metaphysics. These pre-modern assumptions about how the world works may have been de-emphasized, but they’re still definitely there and key to how the system works. One can “spiritualize” away this discrepancy and only apply Thomism to religious truths, but that’s not how Aquinas understood his ideas. Given that attempts to reconcile Catholicism and various other modern philosophies (e.g., Hegelism, Kantian ethics, liberal democracy) were smacked down in the 19th century, I don’t think that reconciling Scholasticism and quantum physics is going to be any more successful. If Thomism is supposed to be the “perennial philosophy” then there’s no room for new insights, and that’s the real tragedy.