Thomist analogical predication - problems

[ficino]

I have various "issues" with Thomism and am not sure whether I'm right when I suspect errors in that system. I post one "issue" here, in case anyone would like to discuss, and I'll make a separate thread for another one.

Aquinas’ doctrine of analogical predication does not seem to escape the difficulty that Thomas himself recognizes for equivocal predication, viz. that demonstrations about God will be vitiated by fallacies of equivocation (cf. ST 1a Q. 13 Art. 5). If some creatures are F, but of God we can predicate F only analogously—let’s call it F~ --how will a deduction go through? The slide from F to F~ will exclude a middle term. Therefore, Aquinas’ natural theology seems unable to “demonstrate” the truth of propositions like “God exists,” although he claims that it can demonstrate such truths.

Thomas had already noted the problem of a missing middle term in Q. 2 Art. 2, and tried to solve it by saying that, though we don't know the cause, we can make a demonstration from the effect, which we know: "however from any effect it can be demonstrated that the cause proper to it exists ... because, since effects depend on a cause, when we posit the effect, it is necessary that the cause preexist." Then to the 2nd objection about a missing middle term he replies that in such demonstrations it's necessary to use the effect in place of the definition of the cause. That's because in proving that something exists, it is necessary to take as a middle term "what the term means" and not the essence, because the question "what is it" follows the question, "does it exist."

The above seems to fail for at least two reasons.
1. Thomas has not solved the problem that in analogical predication, not all that is true of one analogate is true of the other. So F is not identical to F~ and an argument will not go through.
2. When we don't know the nature of the cause, we do not know that it is in fact "propriam", proper/belonging to, a given effect. We don't know that the effect is an effect of the cause whose existence we seek to demonstrate. Isn't Thomas' procedure consistent with arguing from fires that phlogiston must exist, or from light that ether must exist?

Aristotle BTW says that we have to have univocal predication for a demonstration to yield knowledge.

[Bill Wiltrack]

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Could you consolidate your post to make it a bit clearer?

Not quite clear as to what specifically you are asking about?






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[PhilosopherFromDixie]

Have you read Cajetan's Analogy of Names?