Defending Aquinas’ Theistic Proofs, Part 2

Monday, I introduced an epic battle in philosophical history between Thomas Aquinas and Immanuel Kant and gave a brief explanation of each one of Aquinas’ five theistic proofs. Today, I will introduce Kant and his antinomies, which he used to attack the theistic proofs as well as justified metaphysical beliefs. In each one of these, he shows that a metaphysical line of reasoning can be proven and so can its opposite by listing a thesis and an antithesis with proofs for each. Kant insists that categories of understanding beyond the sensible world leads to an antinomy. If he succeeded, then he would have shown that St. Thomas’ proofs are contradictory and that we are unable to use the senses and logic to prove anything beyond the physical realm. These antinomies are listed as:

  1. Thesis: The world had a beginning in space and time. Antithesis: The world has infinitely existed in space and time.
  2. Thesis: Every composite thing that exists is made up of simple parts. Antithesis: Nothing in the world is made up of simple parts and nothing in the world is simple.
  3. Thesis: Appearances of causes are not necessarily determined, instead free agency can will a cause. Antithesis: Every effect must have a cause.
  4. Thesis: Every temporary contingent thing must depend on a necessary being for its existence. Antithesis: A necessary being existing outside of time and space would have no relation to contingent beings.

The Law of Noncontradiction

In addition to the Scriptures and the church fathers which came before him, St. Thomas relied on the philosophy of Aristotle. As such, it is important to understand that for Aristotle, logic was the necessary tool by which humans understand the world and function in it. While addressing the debate between Aquinas and Kant, I will explore two fundamental axioms and compare them to Kant’s first and third antinomies and to show that Aquinas’ theistic proofs are logical in light of these two axioms.

The law of noncontradiction is the most fundamental of all the axioms, whether the discussion regards philosophy, religion, science, or mathematics. Aristotle defined the law when he wrote, “The same attribute cannot at the same time belong and not belong to the same subject in the same respect.” Even though it is not listed as a geometric axiom, no other axioms in the field of mathematics would be possible if contradictions were rationally possible. This is true for all other intellectual disciplines as well. It is the necessary precondition for all rational thought. A cannot be A and ~A at the same time and in the same relationship.

The law does not say that A cannot be A and B at the same time, otherwise a woman could not be both a woman and a wife or a mother could not be a philosopher. We can also say that an object is both circular and wooden. There is no contradiction in predicating both. However, a circle cannot be a circle and not a circle at the same time and in the same relationship. For example, a piece of round wood today could be shaped into a square tabletop next week, but at no time could it be a square circle. It’s also important to note the phrase “in the same relationship.” An object could have a side that is square and another side that is round, like a table with a round top and the bottom of the legs are supported by a square piece of wood. This is an object that is both square and round at the same time, but it is not both in the same relationship.

Kant’s First Antinomy

The law of noncontradiction is a logical guide to coherency and a formal test for truth claims. Kant attempts to use this axiom as a test to show that metaphysical claims are invalid because his thesis and antithesis is A equals ~A in each of his antinomies. I will examine the first antinomy to see if he succeeded. He gives a proposition and then assumes the opposite to show that it cannot be true. In his antithesis, Kant presupposes that the world has a beginning and if true, there would be a period before the beginning of the world called “empty time” to show that “a time must have preceded wherein the world was not.” However, in an empty time, nothing could have started to exist. By this, Kant believes he has shown that it is impossible for the world to begin to exist at some time in the past. What Kant fails to recognize is that the notion of “empty time” is incoherent because time cannot be measured prior to the existence of time. Instead of proving that A does not equal ~A, Kant proved that A does not equal B. The temporal sequence of time (A) is not the same as logical necessity (B). For example, striking a match causes a flame in the temporal sequence of time, but the light from the flame is a cause of logical necessity and not a temporal sequence.

Kant would argue that he believes time and space are not actual things in themselves but only the form of appearances, “hence space cannot occur absolutely (by itself) as something determinative to the existence of things, since it is no object at all but only the form of possible objects.” What he writes here he says also holds for time. Assuming this is true, one could posit the idea of both “empty time” and “empty space” since they are only representations of the actual things rather than things in themselves. Yet, this proposition shows equivocation. One cannot argue for a temporal sequence of time in itself and present an antithesis of time as a form of a possibility. Additionally, Kant does not consider a third alternative, which is one that Aquinas proposes, “God brought into being both the creature and time together.” This puts an eternal God, being the logical necessity of cause, outside of time and the world, thus proving the first antinomy is not the contradiction Kant hoped for in order to invalidate any metaphysical claims concerning the beginning of space and time.

Friday, I will wrap up this series with the discussion on the law of causality and Kant’s 3rd antinomy.

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