Confused by The First Way

[Aristotle]

Unchanging changeable being ≠ self-moved being?

Correct (so it seems), as St. Thomas Aquinas (after demonstrating that self moved movers are reduced to an unmoved mover and a moved) concludes that we arrive at an absolutely unmoved mover, again without considering the case of an unmoved mover which is merely unmoved rather than immovable. Summa Contra Gentiles Book 1, Chapter 13, n.22:

Consequently, one part of the self-moved mover is solely moving, and the other part solely moved. We thus reach the same conclusion as before: there exists an unmoved mover.

[Geremia]

I don't understand how [what you're calling] an unchanging changeable being is not a self-moved being.

[Aristotle]

I don't understand how an unchanging changeable being is not a self-moved being

It's not a self moved being because both (a) it's not being moved and (b) it can be moved by externalities.

[Geremia]

(a) it's not being moved

A self-moved being can be stationary at a certain moment in time, too, though.

Wait, does "unchanging changeable being" even make sense? Isn't that a self-contradiction?

[Aristotle]

A self-moved being can be stationary at a certain moment in time, too, though.

True, but I suppose what I mean to say is that unchanging changeable being is a broader category than self moving being, because unchanging changeable things can encompass both self moving things and non-self moving things. It just requires that the the being in present (a) isn't going through motion and that (b) despite this it nonetheless could go through motion at some future period (whether by its own power or an eternal agent).

Wait, does "unchanging changeable being" even make sense? Isn't that a self-contradiction?

I think it could be if by change we mean that a things potentiality for existence is being actualized, because in that case everything is changing other than God, and God - on top of being unchanging - is also unchangeable. Outside of that, I'm not sure how it could be a contradiction.

Side note: I'm currently in the process of reading Joseph Kenny's "Philosophy of Nature", which is giving a very useful overview of St. Thomas Aquinas's commentary on Aristotle's Physics. I haven't gotten to the unmoved mover part yet, but when I do I'll be sure to illustrate where I go wrong in my thought process.

[Aristotle]

Well, I read through Joseph Kenny's "Philosophy of Nature" and it looks like him and I have come to the same conclusion: Aristotle and St. Thomas Aquinas's argument fails. Quotes from Joseph Kenny:

Aristotle's argument from motion failed to establish the existence of an immaterial first mover

Aristotle had no idea of impetus (or inertia), whereby an agent can communicate to a projectile a transient accidental form {resembling the permanent form of gravity} that keeps it in motion until this form is corrupted by resistance. Aristotle realized that no power could keep fuelling the sun, moon and the planets on their daily course around the earth for eternity unless it had infinite energy. Infinite energy cannot be contained in any body. Therefore the movers of these heavenly bodies must be spirits. These spirits carry out this task in service of the earth below out of love of the supreme principle of the universe, God himself.

But once we introduce the notion of impetus {to say that the heavenly bodies are no different from man-launched satellites kept in motion by the two vectors of gravity and an impetus perpendicular to gravity, which need no refuelling but require only their initial propulsion} then there is no need to postulate spiritual forces to push the moon and other heavenly bodies. Once they were initially set in motion, they go on by themselves, just like natural motion, which Aristotle and Thomas Aquinas said requires no efficient cause here and now.

The big problem I gather from Kenny's account as well as my own independent reading of the Physics is that the fundamental flaw of the First Way is that it presupposes that all motion on earth is in some way essentially dependent on the motion of the heavens (like the Sun and the stars and whatnot), and these heavenly bodies are of course in motion themselves. Thus, the only way they could be moving is if something is moving them, and particularly, something which is spiritual - and thus without potency - here and now. This is why St. Thomas didn't postulate the alternative "a mover which itself is unmoved but movable" because the heavens (although they might come to rest) are eternally (after the fact of creation) in motion and thus the question of it being at rest while moving is never something that pops up because... well the heavens are always in motion. This is the origin of the problem I initially came here to have solved. But in any case, the argument still doesn't work under these considerations because it fails to account for the fact that (1) motion on earth is not essentially dependent upon the heavens and (2) that inertia (or the reception of an impetus, as Kenny describes) could account for heavenly motion without the need of postulating a further mover (especially when we consider that the impetus could be natural - which both Aristotle and St. Thomas Aquinas consider earlier in the work but fail to account for in the development of the First Way).

And, further than this, as Joseph Kenny goes on to explain, even operating under the assumptions of Aristotle and St. Thomas Aquinas, it still requires even further argumentation than is provided in the First Way for us to arrive at God, because it is just as possible that the mover of the heavens is merely an angel rather than God Himself - given that angels are both immobile and capable of moving others. Thus, all things considered, the First Way fails.

Now... at last, I can rest lol. I've been non-stop pouring over the Physics, Summa Contra Gentiles, Summa Theologica, and Joseph Kenny's writing for like a week or three straight. 

[Geremia]

That

the heavens are always in motion

follows from what you said:

everything is changing other than God

But does St. Thomas believe the latter?

[Geremia]

the First Way [...] presupposes that all motion on earth is in some way essentially dependent on the motion of the heavens

St. Thomas and Aristotle seem to side with Mach, not Newton, regarding what would happen if the heavens ceased moving.
Litt, O.C.S.O., Les corps célestes dans l'univers de saint Thomas d'Aquin:

• PDF p. 141:
  "9. De pot., 5, 8, c. Utrum cessante motu cæli, remaneat actio et passio in elementis."
  "Whether, the motion of the heavens ceasing, action and passion remains in the elements?"
• PDF p. 144:
  "9. De caelo, II, l. 4, n. 342. ...cessante motu caeli, omnis motus inferiorum corporum cessaret [...], quia virtutes inferiorum corporum sunt sicut materiales et instrumentales respectu cælestium virtutum, ita quod non movent nisi motæ."
  "if the motion of the heavens were to cease, so too would the motion of all lower bodies, [...]. For the powers of the lower bodies are as matter and instruments in relation to the heavenly powers, and hence do not move unless moved."
  

cf. Assis's Relational Mechanics EU2019 Dynamic Earth lecture, esp. 14:25ff., where he cites Mach's Science of Mechanics (slides 10ff.):

• "The principles of mechanics can be so conceived, that even for relative rotations centrifugal forces arise."
• "Try to fix Newton's bucket and rotate the heaven of fixed stars, and then prove the absence of centrifugal forces."

[Aristotle]

But does St. Thomas believe the latter?

From my readings, no. St. Thomas Aquinas does not believe that everything other than God is changing (at least in the sense discussed in the Physics). There is a genuine belief that somethings can simply be at rest. However, when there is motion, that motion is going to be essentially dependent on the heavens and therefore - since according the Ptolemaic system of cosmology everything is in motion around the earth - the terminus of movers is going to have to be something immaterial.

St. Thomas and Aristotle seem to side with Mach, not Newton, regarding what would happen if the heavens ceased moving.
Litt, O.C.S.O., Les corps célestes dans l'univers de saint Thomas d'Aquin:

I'll admit my ignorance, I don't know who the Mach fellow is, except the little I found on Wikipedia, so I'll refrain from comment on that. However, from the quotes you provided and translated below, it seems to confirm Kenny's conclusion above - as well as my own.

"if the motion of the heavens were to cease, so too would the motion of all lower bodies, [...]. For the powers of the lower bodies are as matter and instruments in relation to the heavenly powers, and hence do not move unless moved."

I can't speak to whether Kenny's interpretation of impetus is correct. I have a hard time understanding how motion can be a transient form communicated to another when I thought whatever is moved is moved by another. But, even setting that aside and assuming a mover is requires at every instant throughout the duration of a motion (which I am most certainly not against), it seems this idea is the most key to the arguments error. After all, we know it's not true because we now know what exactly the powers of the sun pertain to, and that if the sun and even every extraterrestrial thing were to cease being, all of earth would continue to be for quite a bit of time.

[Aristotle]

All things considered, I'm curious as to why the First Way hasn't been dropped by Thomists. Garrigou-Lagrange supports it in his "God, His Nature and His Existence" as well as Edward Feser in his book "Aquinas" which is odd because they take the argument for the First Way and strip it of its cosmological presuppositions (not without good reason, I'd suppose) without understanding that the resultant argument makes little sense in proving what they believe it proves. As, I hope, I have demonstrated in the OP. Here's the argument when we do add the cosmological theory into the mix:
1) Motion is real; 2) Motion is the actualization of potentiality; 3) All potentiality needs an actualizer to actualize it; 4) Therefore all motion requires a mover; 5) Something is in motion; 6) Thus, it requires a mover; 7) The movers of all things on earth are the heavens; 8 ) The heavens themselves are in motion; 9) Therefore something must move the heavens; 10) This mover cannot be material, for the heavens and earth exhaust all the material movers (i.e. there is no material mover except insofar as it is on earth or the heavens); 11) Therefore the mover must be immaterial and immobile.

Unfortunately, it only ever gets us to an angelic substance, not necessarily God. Even more reason to reject the First Way, in my opinion.

[Geremia]

I don't know who the Mach fellow is, except the little I found on Wikipedia, so I'll refrain from comment on that.

Watch Assis's lecture; it's only 32 min.:

Interestingly, there are experimental tests of which view, Mach's or Newton's, is correct (slide 25 of his lecture; Relational Mechanics and Implementation of Mach's Principle with Weber's Gravitational Force, §24.5 Experimental Tests of Relational Mechanics, pp. 460-74). The experiments require measuring lengths down to 1 part in 10²⁹, which is currently beyond today's technological capacities (cf. Planck length = 1.6×10^-33 m), but will be feasible in the future, with the development of more precise measurement apparatuses.

[Geremia]

I have a hard time understanding how motion can be a transient form communicated to another when I thought whatever is moved is moved by another.

A "transient form communicated to another" is not an instance of "whatever is moved is moved by another"?

[Geremia]

if the sun and even every extraterrestrial thing were to cease being, all of earth would continue to be for quite a bit of time.

How do you know that?

[Aristotle]

Watch Assis's lecture; it's only 32 min.:

Very interesting. I will give it a view.

A "transient form communicated to another" is not an instance of "whatever is moved is moved by another"?

After some consideration, I suppose it would be an instance of "moved by another" given that the form would be the mover and the substance would be moved.

How do you know that?

Well the sun does two main things (as well as a few others, but these two are the most important for life on earth): it heats and it brings energy. If the sun disappeared tomorrow, we would cease to have an addition of heat and energy. But we already have a lot of energy on earth, and heat. I'm not saying life would last long, but what I am saying is that motion in general would continue. But even if that weren't true and the motion of the heavens ceasing would mean an immediate ceasing of all motion on earth, given that impetus can be natural rather than imposed (such as the impetus of objects to fall toward one another), the fact that the heavens are in motion would not necessarily indicate a mover of the heavens.

[Aristotle]

Interestingly, there are experimental tests of which view, Mach's or Newton's, is correct (slide 25 of his lecture; Relational Mechanics and Implementation of Mach's Principle with Weber's Gravitational Force, §24.5 Experimental Tests of Relational Mechanics, pp. 460-74).

Really?! Incredible! I got to the end of the video and was getting worried I'd have to die with another mystery lingering in my mind.

The experiments require measuring lengths down to 1 part in 10²⁹, which is currently beyond today's technological capacities, but will be feasible in the future, with the development of more precise measurement apparatuses.

Very interesting... so if I'm apprehending things correctly, this experiment would allow us to know if space is absolute - as Newton postulated - or relative, or relational, yes? Now that's certainly exciting. I'm currently reading Edward Feser's Aristotle's Revenge and finished the section on space and time. It seems his opinion is strongly against both Newton's absolute space and a relational view of space. But he doesn't (in my opinion) develop his own opinion on what the nature of space really is - except that he noted that space requires relations but is not reducible to it. What is your opinion?

[Geremia]

I'm currently reading Edward Feser's Aristotle's Revenge and finished the section on space and time.

You'd like Universe without Space and Time: An Essay on Principles for Relational Cosmology Drawn from Catholic Tradition and Empirical Science by Fr. Victor Warkulwiz, M.S.S., Ph.D.; he's a proponent of Assis's relational mechanics.

[Aristotle]

You'd like Universe without Space and Time: An Essay on Principles for Relational Cosmology Drawn from Catholic Tradition and Empirical Science by Fr. Victor Warkulwiz, M.S.S., Ph.D.; he's a proponent of Assis's relational mechanics.

I'll certainly give it a read. Only problem is that it seems the book is no longer available.

[Geremia]

Only problem is that it seems the book is no longer available.

The EPUB of it is.

[Aristotle]

The EPUB of it is.

When I click the link it says "No epub format for the book 5028."

[Geremia]

When I click the link it says "No epub format for the book 5028."

Try this link.