First Way, Part IV: The Cascades

Previous episodes in this exciting series, now drawing toward its thrilling climax:

• Background lays out the history of the Argument from Motion and the impatience of those who demand that it prove more than it asserts to prove (e.g., that it prove that Jesus is Lord or some such thing, as if the objector were genuinely concerned about this shortfall).
• Part I A Moving Tale discusses the concept of "motion" used in the Argument from Motion, and how this is persistently misunderstood today. 
• Part II Two Lemmas demonstrate that 

1. Whatever is being actualized right now is being actualized by another. 
2. There cannot be an infinite regress of instrumental changers,

• Part III: The Big Kahuna combined the two Lemmas into the first theorem and its corollaries

A number of objections and misunderstandings were also addressed in these prior posts.

We are now ready for Thomas' throwaway teaser: "and this [the unmoved mover] is what all men call God." Folks who have never read any further (if they have even read that far) are often puzzled. How do you get God out of that? TOF hears them cry in bewilderment.

The answer lies in the several hundred further Questions and Articles in which these points are developed. In the interests of brevity, a few subsequent proofs will now be stated without extensive arguments, but ought to be intelligible in the light of what has already been said.

First Way, Part III: The Big Kahuna

Previous episodes in this exciting series, now drawing toward its thrilling climax:

• Background lays out the history of the Argument from Motion and the impatience of those who demand that it prove more than it asserts to prove (e.g., that it prove that Jesus is Lord or some such thing, as if the objector were genuinely concerned about this shortfall). The initial proposition in Euclid does not prove every conclusion in Euclid, and the same is true in other sciences as well.
• Part I A Moving Tale discusses the concept of "motion" used in the Argument from Motion, and how this is persistently misunderstood today. Kinesis means the actualization of a potential, so "change" is a better summation of the concept than the modern term "motion," which to the our ears sounds like local motion only.
  

  Recall that we are using "motion," "change," "actualization [of a potential]," and "kinesis" as synonyms.

• Part II Two Lemmas demonstrate that 

1. Whatever is being actualized right now is being actualized by another. In many cases, a thing is changing as a whole because it is being changed by one of its parts. The cat crosses the room to the milk dish because its legs are moving it; its legs are being moved by its muscles, etc. This is because the changer must be actual while the changee must be in potency and what is in potency cannot make something else actual.
2. There cannot be an infinite regress of instrumental changers, since an instrumental actualizer has no power to actualize diddly squat unless it is concurrently being actualized itself. Obvious instrumental changers include... well, instruments: golf clubs, clarinets, et al., which have no power to strike balls, make music, etc. unless they are concurrently being employed by a golfer or musician. Not all instruments are obvious: e.g., the muscles are used instrumentally by the nerves to move the arms. But not all changers are instrumental, either, and such "accidental" series can in principle (if not in fact) regress without limit.

A number of objections and misunderstandings were also dealt with in these prior posts.

We are now ready for the Big Kahuna:

First Way, Part I: A Moving Tale

OK, TOF has finished "In Panic Town, On the Backward Moon" and is ready to resume what he joshingly refers to as "real life."

Back to the Argument from Motion (See Preface)

Getting 'Motional

[T]he arguments require the appreciation of certain metaphysical principles that are unfamiliar or seem archaic to the contemporary philosophical mind...  In particular, the notion of causation employed by Aquinas in the arguments has a decidedly obscure ring to modern ears.
-Oderberg, ‘Whatever is Changing is Being Changed by Something Else’

Part of TOF's herculean effort here will be to translate, as much as he is able, those original items into more modern lingo. This is not always quite possible and not always well-advised, because words in different languages in different eras do not always divide thought into the same categories. But, Excelsior!¹

Clarifications
1. Excelsior. As all men know, this is a packing material used as dunnage.

First Way, Some Background

Sr. M. Amelia, IHM
explicator of logical thought,
or else.

Sr. Amelia: And so, class, as we see from Postulate 9 and Axioms 6 and 2, supplements of the same angle are equal. Yes, Billy?
Billy: But, Sister, I don't see how this proves that a point equidistant from the endpoints of a line segment lies on the perpendicular bisector of the line segment!
Sr. Amelia: It doesn't, Billy. That comes later. Now class, let us proceed to showing that the vertical angles of two intersecting lines are equal.
Billy: But, Sister! How will that show that a point equidistant from the endpoints of a line segment lies on the perpendicular bisector of the line segment!
Sr. Amelia: You must have patience, Billy. You can't prove everything all at once, so you must prove something first.

Over on Briggs' place a discussion of the so-called Argument from Motion is being served up piecemeal, literally a paragraph at a time. Thus, by the time the esteemed Statistician to the Stars completes his Herculean labors, the final proof will be obvious, inasmuch as the Second Coming (and/or Heat Death of the Universe) will have taken place and all will see clearly and not as through a glass, darkly.