Thanks Linus. I am not sure why you think I am pushing some modern philosopher in particular simply because I seek clarification on points re Aquinas that naturally arise in the mind of a non medieval thinking person. Yes, I am here to understand Aquinas better, if you are the person you speak of then I am all ears! Unfotunately the link you’ve offered doesnt seem wholly relevent to my main concern here re Aquinass understanding of induction though other contributions have.
I thought my Aquinas commentator was faiirly well respected - he did a 1905 translation of SCG afterall ( Joseph Rickaby SJ ). He was quite certain that the First Way of Aquinas was based on that of Aristotle and the local motion of the planets. He was clear that this example from local motion was problematic. I am not sure of the implications for the First Way as a whole. Anyways, this post is more about the certainty that attaches to Aquinass demonstrations from effects.
What I have realised by this discussion is that demos from effects provide certainty re the existence of a cause but apparantly not re a comprehensive understanding of the character of the cause.
Not familiar with Rickaby. However, there was a revival of Thomism beginning in the late 1800’s and continuing to this day. And of course there are various explanations of exactly what the Five Ways were all about. That is why I referred you to Feser, his works and his blog. I’m surprised that you didn’t find what you needed in the link. Of course, if you are only interested in a discussion of " a posteriori " and " induction, " then your best resource is our own ( he would smile at that ) Hicetnunc. He is very obliging. He is worth listening to.
As far as Thomas’ use of Aristotle’s Clestial Movements is concerned, I refer you to page 39 of Feser’s " Aquinas " where he cites Rickaby ( how could I have forgotten that ) at p. 67 of his " Scholasticism " ( cf S.T. 1. 32. 1 ). Quoting Rickaby, Feser says, " …As Aquinas says with respect to the Ptolemaic astronomy accepted in his day, ’ the suppositions that those astronomers have invented need not necessarily be true; for perhaps the phenomena of the stars are explicable on some other plan not yet discovered by men…’ "
The Five Ways as discussed in the S.T. do not refer to the " Celestial Movements. " Each begins in some easily observable movement and then moves on to the underlying metaphysical causes ( the act and potency principles of being ) which account for their existence and the fact that they are effects whose cause is God.
It is only in the S.C.G. ( Book 1, ch 13, paras 27-28 ) that Thomas refers to the " spheres."
" 27] Nor is it against this argument that the movers of the lower spheres produce an everlasting motion and yet are said to be moved by accident. For they are said to be moved by accident, not on their own account, but on account of their movable subjects, which follow the motion of the higher sphere.
[28] Now, God is not part of any self-moving mover. In his Metaphysics [XII, 7], therefore, Aristotle goes on from the mover who is a part of the self-moved mover to seek another mover—God—who is absolutely separate. For, since everything moving itself is moved through appetite, the mover who is part of the self-moving being moves because of the appetite of some appetible object. This object is higher, in the order of motion, than the mover desiring it; for the one desiring is in a manner a moved mover, whereas an appetible object is an absolutely unmoved mover. There must, therefore, be an absolutely unmoved separate first mover. This is God. "
And this has nothing to do with the validity of the proof as should be evident. I call it, " covering all conceiveable bases. " He does the same thing in first three of the Five Ways in the S.T.
Nor should you think that motion in Aristotle or in Thomas is limited to local motion. Rather it meant any type of movement or change, even thought. His arguments are valid then for every type of movement imaginable, including local motion.
Now as far as " induction " concerned, Feser discusses this on pg 43 of Aquinas, but you should begin reading at the top of pg 42 to get the full flavor.
Linus2nd