Defending Aquinas’ Theistic Proofs, Part 3

Last Friday I introduced a series on faith and reason through the lens of Thomas Aquinas. Monday and Wednesday, I pitted Aquinas’ arguments against Kant’s antinomies to show the fallacy in Kant’s reasoning and the logic in Aquinas’ theistic proofs. Today, I am wrapping up this series by showing how the law of causality refutes Kant’s 3rd antinomy.

Kant’s 3rd Antinomy

To review all of Kant’s antinomies, go here. But for the ease of this discussion, his 3rd antinomy states:

Thesis: Appearances of causes are not necessarily determined, instead free agency can will a cause. Antithesis: Every effect must have a cause.

Law of Causality

Wednesday, I mentioned two fundamental axioms. The first, law of noncontradiction, was explained in the last blog post. The second axiom, the law of causality, stands in relation to the law of noncontradiction’s formal test. Causality concerns the quality of motion we call change, and its logical sequencing points to a relationship between temporal events.

Example: event A causes event B. There are objections to this temporal sequencing, which I will address later. For now, I will focus on what causality is, how it is a first principle, and how it is supported by the law of noncontradiction. In a practical scientific way, causality can be shown in a series of events. For example, putting water on a hot stove will cause the water to boil, which will cause the water molecules to expand and vaporize into air.

For causality to be established as an axiomatic corollary of the law of noncontradiction, we must recognize it as a formal principle that is necessarily true. To do that, I will start with the definition: something that gives rise to an effect. The term effect denotes the notion of cause. This is more clearly seen when we say, “Every effect must have a cause.”

While we cannot prove the law of causality through sense perception, it is a logically prior supposition necessary to understanding the phenomena we observe. Thus, it is a self-evident principle. Like the law of noncontradiction, it must be true for the world and humanity to function. It is a universal necessity because if we could not rely on the law as valid, then the absence of the law would violate the law of noncontradiction. It is contradictory for water to boil and its molecules to expand and vaporize into air one time and then turn to ice another time. A clever person might point out A cannot be A and ~A at the same time and in the same relationship; therefore, water applied to heat could boil at one time and turn to ice at a different time. My response to that would be to point out that the law of causality cannot contradict itself.

Logical Errors with Causality

I will admit that logical errors can sometimes occur when applying the law of causality. Faulty causal generalization and post hoc are such examples. Post hoc ergo propter hoc, which translates as, “after this, therefore because of this,” concludes that since A happened before B, A must have caused B. A friend joked that buying his kids an Elf on the Shelf caused unusual occurrences in his house, even though there are more likely explanations than a sentient toy. However, logical fallacies do not negate a true causal sequence of events. Further, it is important to distinguish between necessary condition and sufficient condition. A necessary condition is a circumstance that must be present for an event to occur. A sufficient condition is a circumstance that must produce the event. The presence of oxygen is necessary but not sufficient for combustion, for example.

Aquinas’ 2nd Theistic Proof

With this understanding of causality, I will compare Kant’s third antinomy with St. Thomas’ efficient cause, which states that efficient cause is the primary source of change, like the knowledge a carpenter has when creating a table. Just like a table is unable to be its own cause, the world came into existence through a primary efficient cause.

Kant argues that the law of nature and freedom are at odds by proving on the one hand that “no absolutely first beginning of any series is possible during the course of the world” and makes a separation between temporal sequencing and change. (Odd that he did not do so with his first antinomy).

However, he comments on his antithesis that because we experience change, then we know a priori “such an unceasing sequence of being and non-being is possible.” Since these two propositions are contradictory, both cannot be correct. This is, of course, Kant’s point in that since both the thesis and antithesis can be proven, then human knowledge of such matters is unattainable.

False Contingency

Yet, only one of his premises is valid according to the two axioms of noncontradiction and causality because what Kant presents is a false contingency when he writes, “We must assume an absolute spontaneity of causes whereby they can begin on their own a series of appearances that runs according to natural laws” because spontaneity of cause is contradictory to the axioms established above. To that, Aquinas would say, “A false impossibility does not follow from a false contingency.”

Aquinas, however, recognizes that “if mover and moved be united together in some subject accidentally, and it be found that a certain thing is moved without its being a mover, it is probable that a mover is to be found that is not moved.”

What he is saying is that everything that moves must have a cause for its motion. If a pool player hit the cue ball with a pool stick, and the cue ball hits another ball which hits another ball, it would be recognized that each object that moved was caused to move by another. The movement of the stick caused the cue ball to move, but the stick also had to be moved by a primary causal agent.

Aquinas gives a few other examples with regards to a healer needing to be healed and a teacher needing to be taught. If we continue to go backwards to find the causal agent of each thing moved or healer healed, we find another agent that must be moved until we are either in infinite regress or until we reach the single primary cause of all that there is, and that the primary cause, by definition of primary, cannot have been moved by anything other than itself.

Because of the flaws, Kant’s antinomies do not do the damage to Aquinas’ theistic proofs that some claim that it does. Instead, when the two philosophical systems are exposed to the light of natural law and human reason, Aquinas’ proofs fair more favorably as it is logically consistent according to the two axioms I discussed, and it is more consistent with our natural sensual understanding of the world. I conclude, therefore, that Aquinas’ theistic proofs are logically consistent with natural human reason.

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