EAllusion wrote:It's dated philosophy, but you can grant scholastic casual reasoning to accept that a first cause exists without thinking that a case has been made that this first cause is a deity. All of Aquinas's five ways involve a conclusion that says "and this is what we call God." None of those cases effectively establish that what he set out to prove has to be god-like in its attributes.
This is not the case at all. Aquinas makes it pretty clear in
Summa Theologiae the purpose of these 5 ways is
not to show God exists, he does this because the
Summa Theologiae is meant to be a textbook for men studying for the priesthood. Aquinas doesn’t even get to showing that the 5 ways prove just 1 thing exists and not 5 things until much later in the text ( Part 1, third article of Question 11). He has a whole other bevy of arguments that attempt to demonstrate why the thing proved in the 5 ways must be eternal, powerful, immutable, and wholly good. In his
Summa Contra Gentiles he mentions that one shouldn’t use arguments to prove the “unique” truths of Christianity because they will always fall short against “The Fool” (Book 1, 9th chapter).
Aquinas has much longer and detailed arguments for traditional theism in his other works outside the
Summa Theologiae, the 5 ways are simply not an effort to prove classical theism, nor does is represent his better arguments.
EAllusion wrote:Here's a good reading of what those arguments entail
Those readings don’t show the steps of the argument and why it works or doesn‘t work, which sort of takes away from their force. Here is a deductively valid reconstruction of the 1st way from the actual text:
(P1) Some things are moved.
(P2) If something is moved to being X, then it is potentially but not actually X.
(P3) If something moves a thing to be X, then it (the mover) is in a state of actuality relevant to X.
(C1) If something were to move itself to be X, then it would both potentially but not actually X and also in a state of actuality relevant to X.
(Proof for C1) Conjunction and Modus Ponens of P1, P2, P3
(P4) But it is not possible for something to both potentially but not actually X and also in a state of actuality relevant to X
(C2) It is not possible for something to move itself to be X
(Proof for C2) Modus tollens, C1, P4
(P5) If it is not possible for something to move itself to be X, then if something is moved, it is moved by something else.
(C3) If something is moved, it is moved by something else
(Proof for C3) Modus Ponens, C2, P5.
~Fun fact here, Aquinas actually spend about three times the amount of text for the entire 5 ways on just defending C3 in
Summa Contra Gentiles (Part 1, chapter 13)~
(P6) If the series of movers were to go on infinitely, then there would be no first mover.
(P7) If there were no first mover, then there would be no motion.
(C4) There is a first mover
(Proof for C4) Modus tollens, P1, P7
Money Shot: That first mover is the thing that everyone takes to be God
So taking into account the actual fact that this isn’t an argument for classical theism, what makes it so terrible? My biggest objection is to (P6) because it fails to take into a account the distinction between an actual regress (which doesn’t prove there is no “first mover”) and the impossibility of achieving an infinite collection by single addition. ETA- And this wasn't really shown until the
Principia Mathematica in the 20th century.