How Aquinas confuses the First and Second way

[balto]

Right, but do you agree that this process can be over time? The way I understand it is that all that needs to be simultaneous is that the initial cause that starts the per se causal chain needs to be in existence as the source of the action that moves the entire instrumental chain. If that initial cause were to go out of existence, say half way through the execution of the causal chain, then the remainder of that uninstantiated causal chain would not be moved.

Yes, I think your analysis here is correct.

I would say that the immediate cause of the rock moving (or at least in the initial accelerating) is the stick. The stick (with an artificially imposed final cause of moving rocks) immediately moved the rock, but the motion of the stick was caused by a temporally earlier cause and effect transaction between the motion of the hand and the motion of the stick, that was cause by an earlier cause and effect transaction between the motor neurons that triggered the muscles to contract, which was caused by processes in the brain, etc…

What do yo think? The only thing that need be simulateous in this description, in terms of the entire sequence of actions and the end goal of moving the rock, is the existence of the initial mover, and all the instrumental causes in between, and the rock that moves, even though the events may be spread out over time.

God bless,
Ut

I agree with this also. This illustrates why quibbling over scientific details is missing the point. The whole point of the rock and staff example is to get someone to think of the series of instrumental causes and the existence of the unmoved first mover in this causal chain. We’re not trying to make a scientific point, but a metaphysical one. If the point we are making is wrong, then things can change themselves spontaneously for no reason. I don’t know of anyone who wants to accept that.

 

[Linusthe2nd]

"Or we could posit natural forces such as gravity"
Linus this is poor Physics, gravity can only ever cause acceleration, never uniform motion which you seem to be talking about here?

This “principle” is the problem which is causing all the above somersaults.
I see two problems with this “principle” and the way you are using it:
(i) you’ve put it very vaguely if we are talking about the First Way.
I think you mean to say “whatever is moving must be being moved by another.”
I think that is the most accurate rendering of Aristotle in Latin, or do you disagree?

(ii) If the First Way is truly aposteriori then the certainty of this principle must also be somehow derived from observation of the sensible world, presumably by induction from everybody’s consistent observation of motion in everyday life.

And here’s the logical problem. If this principle is true it must be true of local motion. And if true of local motion it must hold for all local motion.

Now Newton showed that all observed sensible motion is either due to continuously applied sensible force (resulting in ongoing acceleration) or temporarily applied force (resulting in initial acceleration terminating in uniform velocity) no exceptions.

Therefore the principle you enunciate above that is allegedly aposteriori is in need of a slight correction if we accept it’s truth is aposteriori rather than apriori.

Namely: “whatever is moving was put into motion by another” is the most we can consistently say. We cannot say “whatever is moving is being moved by another” because that is only true of an object demonstrating continuously accelerating motion (or constant velocity in the face of friction).

The problem is instead of questioning the truth of the principle you are questioning the truth of reality and positing a worldly “god of the gaps” explanation simply because “there must be one.”

This seems to be a logical flaw in your methodology if the truth of the First Way is truly aposteriori. If you believe your methodology is valid then in fact you seem forced to accept that your understanding of the First Way is in fact primarily apriori metaphysical.

Your principle of movement “whatever is moving is being moved by another” then becomes a metaphysical sacred cow that is non-falsifiable by empirical observations or experiments and Newton hasn’t gone far enough - there must be more for the Physicists to discover/understand in the sensible world.

However I believe this principle is aposteriori and Newton has fine tuned our understanding of local motion which means Aristotle’s principle of motion has to be amended from “whatever is moving is being moved by another” to “whatever is moving was put into motion by another.”

How this correction of Aristotle’s principle affects the First Way I don’t know.

It may have more serious implications for ontological principles of change perhaps.
If of sensible reality it cannot be said that “whatever is moving is being moved by another”
then from where does the truth of "“whatever is changing is being changed by another?”

Perhaps we can only say “whatever is changing began its change by another?”

The only efficient cause of pertinence wrt local motion is the fuel burning and expanding and providing the impetus. There is no prior chain of local motion beyond that from what I can see. Of course there are prior efficient causes to the liquid oxygen/hydrogen being there.

The problem I see with this tortured “modification of nature” hypothesis is that a self-mover must have a different constituent “part” from which the internal agent act arises.
In living things this is the soul. A projectile does not have a soul - though it would be logical for you and Linus to posit one wouldn’t it? Afterall it is internal self-movement which defines “life” (the ability to move oneself).
But of course we today would not posit a soul in a projectile so the problem is how can the atoms being moved be moved by a “change in nature” of the same atoms? Whence the distinct “part” of the cannonball that causes act of the other part of the cannonball and makes it a self mover?

Will respond when I get time.

Linus2nd

 

[Richca]

Some thoughts on motion or change in Aquinas and Newton

 

[Richca]

Some thoughts on motion or change in Aquinas and Newton

 

[Richca]

Indeed, according to science, the entire body of the universe is expanding at an accelerating rate.

Incidentally, according to Newton’s first law of motion, this would require an external mover or force; the unmoved mover of Aristotle/Aquinas.

 

[Blue_Horizon]

omne quod movetur, ab alio movetur.
All that is moved, is moved by another. Movetur is the passive form of moveo. Movetur can be “He is moved, she is moved, it is moved, whatever is moved”. Your construction would be “omne quod movens, ab alio movetur”.

UUT the point is that this principle can mean at least 5 different things because it is highly ambiguous in the various translations I see given in these interminable discussions of the First Way. Yours and Linus’s are no exception here.

When Linus said “Motion must be caused by something” I was hoping he would respond rather than your good-self what sort of motion he means (continuous motion or merely set in motion).

You translate it as “All that is moved, is moved by another” (thanks for the Latin lesson). I was really more concerned for the grammatical aspect rather than the grammatical voice. Can you advise whether you believe we are talking present passive continuous or present passive simple/completed/perfect? (ie “whatever is being moved (ongoing) …” or “whatever has been moved (from rest)…”.

I believe both are implied by the Latin yet only one translation is compatible with Newton’s first law."

It is interesting that by using this construction, it leaves the cause of the motion indeterminate. It need not be an efficient cause. Thus the source of the motion can be anything. Any other, whether that be another physical object or caused by the object’s very nature. It is a very general metaphysical principle.

I believe this is mistaken UUT. At least wrt the First Way which is the topic under discussion here remember. We are talking chains of locomotive causality (amongst other things). In such chains, motion requires multiple agent causes. Sounds efficient causality to me.

Even Feser allows this (sequential causality) in the temporal order and, to my great surprise above, Linus too apparantly.

What defines life is no trivial matter and is still being debated today. See this link for an example of someone who denies that there is any such distinction between living and non living things and a response from Ed Feser.

Lets not get overly global on this but specific to the discussion at hand. Linus attempts to posit an alternative cause for const velocity motion (to be consistant with a distorted translation of the above principle) that essentially says, in Aristotle’s terms, that matter in motion has a soul (but simpler than vegetative life). Its interesting, consistant but, in this day and age, beyond the pale. Its also not necessary. I maintain this “logical imperative” to find such a cause is misguided. Aristotle’s principle does not really require we need to find a “cause” for uniform velocity from what I can see.

It is simpler to assume Aristotle’s principle has perhaps been misunderstood and mis-translated by hacks both Physic and Metaphysic.

…anything with mass [presumably in motion] can be analyzed … at the micro level where causation seems to be more apparent.

I really have no idea what you mean or how an agent cause of motion can be found that is not at the same time the moving mass in question? Aristotle says this is impossible.

There is no need to posit a soul in this discussion except with regard to living things.

Yes I agree, but if I understand Linus correctly one of his three alternatives, strictly speaking in an Aristotelian sense, essentially seems to do just that.

 

[Blue_Horizon]

As I’ve said above, “omne quod movetur, ab alio movetur.” is not restricted to efficient causes alone. You also have to factor in formal and final causation. The material and the formal causes are intrinsic to all physical things. The final and efficient causes are extrinsic. Is it so much of a stretch to postulate that an efficient cause can create a change in another in terms of velocity that is preserved in terms of constant motion by the material and formal causality?

But you seem to be doing exactly what this thread is criticising - mixing principles between different Ways of Aquinas.

In the First Way the focus is on more demonstrable experimental aposteriori arguments and chains of temporal causality involving visible motion. Sounds like efficient causality to me.

And its not like sustaining motion has no cause whatsoever in classical physics. It requires that objects have mass, right?

Of course, though inertia and mass may not inherently be the same thing. Nevertheless even Newton agrees with Aristotle that “setting mass in motion” demands an instrumental/efficient cause and failing what we call a miracle (or a soul) that will be via another material entity.

However “continuing mass in constant motion” does not seem to require any sort of agent/instrumental cause whatsoever - unless we misunderstand Aristotle’s principle as I may be the case as already explained below.

If you can show that my translation of Aristotle’s principle cannot hold that would be more interesting than this chasing of a cause (of whatever mode) that need not be found anyway.

 

[Blue_Horizon]

(Continued from previous post)

Newton’s law of inertia does not nullify Aquinas’ first proof nor can it. The theoritical law of inertia is a physical law based on physics which is limited to the physical, quantifiable, and sense observable world. The first mover of Aquinas is metaphysical, trans-sensible, transcendent, separate from the world and known only by the intellect. To reach the metaphysical unmoved mover among a series of moved movers whether these moved movers are one or several or more, at some point, one has to transcend the physical, observable world. And this can be done rather swiftly, indeed, immediately as in the case where God immediately works in our souls as St Paul says “It is God who worketh in you both to will and to work for His good pleasure.”

If Aquinas starts to demonstrate a proof based on observations of the sensible world then, in theory, that proof is falsifiable by other observations that may show his observations (or his principles inducted from observation) to be mistaken in any way.

This is exactly the approach Aquinas appears to assert in the First Way.

 

[Blue_Horizon]

Well you seem to have defined cause and effect in such a way that it necessitates that causes and effects be temporally separated.

We’re going in circles.
Please supply a clear example of a chain of locomotion where cause and effect are not temporally separated. I don’t think any scientist since the enlightenment has found one which is why we today define cause and effect in this way.
I don’t think I have been brain-washed but it is possible.

That’s because Aquinas, you, and I are equivocating when we use the terms “cause” and “effect.” The conception I am trying to give to you and the one you are actually thinking of are not the same because we obviously are not agreeing on terminology. It is probably the case that I am right in my way and you are right in your way, but you are having difficulty understanding how I am right in my way because you are taking the words that I am using and taking them to mean something other than what I am meaning them to be.

At last agreement. Though (myself), Gilson and many others have been saying this about the First Way for ages. As was mentioned at least three times below in this discussion .

 

[utunumsint]

UUT the point is that this principle can mean at least 5 different things because it is highly ambiguous in the various translations I see given in these interminable discussions of the First Way. Yours and Linus’s are no exception here.

Yes, it is a very general rule. Feser, for one, offers at least three different formulations of it.

The Scholastic principle of causality states that any potential, if actualized, must be actualized by something already actual. (It is also sometimes formulated as the thesis that whatever is moved is moved by another or whatever is changed is changed by another. But the more technical way of stating it is less potentially misleading for readers unacquainted with Scholastic thinking, who are bound to read things into terms like “motion” or “change” that Scholastic writers do not intend.)

If you look at Aquinas’ chapter on the proofs for the existence of God in the summa contra gentiles, you will find his third way of proving the principle in question is precisely based on this discussion of active and passive potentialities:

dhspriory.org/thomas/ContraGentiles1.htm#13

[9] In the third way, Aristotle proves the proposition as follows [VIII, 5]. The same thing cannot be at once in act and in potency with respect to the same thing. But everything that is moved is, as such, in potency. For motion is the act of something that is in potency inasmuch as it is in potency. That which moves, however, is as such in act, for nothing acts except according as it is in act. Therefore, with respect to the same motion, nothing is both mover and moved. Thus, nothing moves itself.

Now in the previous paragraph 8, he already mentions that he considers motion inherent in the nature of a substance is still moved by another on account of its generation. So whether you like it or not, Aquinas did have a very broad view of the this concept of motion. And honestly, that is why this discussion is metaphysical rather than physical. It rests on generalized observations from a variety of sources.

When Linus said “Motion must be caused by something” I was hoping he would respond rather than your good-self what sort of motion he means (continuous motion or merely set in motion).

You are free to ignore my contributions. I am not an expert, but I do enjoy a dialogue with my peers on this forum. I may not convince you of my position, but I am certainly trying to engage your arguments, if not for you, then for myself and others.

You translate it as “All that is moved, is moved by another” (thanks for the Latin lesson). I was really more concerned for the grammatical aspect rather than the grammatical voice. Can you advise whether you believe we are talking present passive continuous or present passive simple/completed/perfect? (ie “whatever is being moved (ongoing) …” or “whatever has been moved (from rest)…”.

I believe both are implied by the Latin yet only one translation is compatible with Newton’s first law."

Again, if I am to go on my learning of Latin, I would simply use the passive voice as I’ve written it as the most literal translation. If something more precise was intended, then Aquinas would have elaborated on the principle using additional words, as you have done. And he does elaborate, throughout his chapter on the summa contra gentiles in his three ways of proving the principle. You can read into how he understood the principle using those three ways. Context really matters when doing translations.

I’ll respond to the rest of the post later on today.

God bless,
Ut

 

[balto]

We’re going in circles.
Please supply a clear example of a chain of locomotion where cause and effect are not temporally separated. I don’t think any scientist since the enlightenment has found one which is why we today define cause and effect in this way.
I don’t think I have been brain-washed but it is possible.

I believe I have already explained how constant velocity local motion is not an instance of real change numerous times in this thread already. How the character string “cause” and “effect” are defined by scientists is not interesting to me. You evaded my question:
"balto:

At this frozen instant, is there a reason that the rock is accelerating? And if so, what is that reason? No appeals to prior moments are allowed.

Methinks the reason you avoided answering it is because answering in the affirmative places you in agreement with Aquinas and answering it in the negative puts you at odds with sanity.

At last agreement. Though (myself), Gilson and many others have been saying this about the First Way for ages. As was mentioned at least three times below in this discussion .

What are we in agreement over? That language can be ambiguous? Everybody knows that. I think what we should be in agreement over is that it is not sufficient to refute someone else’s argument by constantly redefining all their terms. You need to refute them on their own terms instead of simply saying “well I don’t think those terms should mean those things.” It seems to me based on your earlier comments that you essentially agree with what we are saying but just don’t want to call it a cause and effect.

 

[utunumsint]

I believe this is mistaken UUT. At least wrt the First Way which is the topic under discussion here remember. We are talking chains of locomotive causality (amongst other things). In such chains, motion requires multiple agent causes. Sounds efficient causality to me.

Right - So this conversation is jumping all over the place. I wonder if folks could simply focus on the chapter in summa contra gentiles so that we can agree on the source material for our discussion. This also happens to be the chapter that thinkandmull wants us to respond to, so it is the most on topic.

dhspriory.org/thomas/ContraGentiles1.htm#13

I propose a phased approach.

In phase 1, lets try to define the arguments that Aquinas makes from motion, as best we can.

If we can come to a consensus on phase 1, without regard to modern or classical physics, then we can move on to establish how the principles may be violating the canons of modern or classical physics in phase 2.

What say you all?

God Bless,
Ut

 

[balto]

Right - So this conversation is jumping all over the place. I wonder if folks could simply focus on the chapter in summa contra gentiles so that we can agree on the source material for our discussion. This also happens to be the chapter that thinkandmull wants us to respond to, so it is the most on topic.

dhspriory.org/thomas/ContraGentiles1.htm#13

I propose a phased approach.

In phase 1, lets try to define the arguments that Aquinas makes from motion, as best we can.

If we can come to a consensus on phase 1, without regard to modern or classical physics, then we can move on to establish how the principles may be violating the canons of modern or classical physics in phase 2.

What say you all?

God Bless,
Ut

Yes, I think this is a good idea. Sorry, I didn’t mean to sound cranky in my last post and apologize to you and Blue Horizon if that is how it came across . But I still suspect the real disagreement is over semantics and not content.

 

[utunumsint]

Perfect. I think we could start with paragraph 5, which is where he starts the first way he proves the principle that that all things that are moved are moved by another. Here he sets out the principles of his first proof that he goes on to use in paragraphs 6 and 7.

Paragraph 5 -The first way is as follows.

i.e., the first way to prove the principle that everything that is moved is moved by another.

Point 5.1 If something moves itself, it must have within itself the principle of its own motion; otherwise, it is clearly moved by another.

I guess this means that whatever is self moved or moving must by nature be able to do so. So a bullet does not naturally accellerate and move through space. I think I can agree with this. Any objections?

Point 5.2 Furthermore, it must be primarily moved.
Point 5.2.1 This means that it must be moved by reason of itself, and not by reason of a part of itself, as happens when an animal is moved by the motion of its foot. For, in this sense, a whole would not be moved by itself, but a part, and one part would be moved by another.

I think I can agree with this, but I’m not sure. Basically, I take him to mean that anything that has parts that would have to work together to move illustrates the principle that everything that is moved is moved by another. Because composite being is only moved because a part of it is moving, like its feet. But wouldn’t this motion all be self contained, and have its ultimate origination in the person or animal deciding to move one way or another? Perhaps he will unpack this point later on. Maybe in itself, it is enough that any animal has parts that ultimately depend on one another for their motion.

Point 5.3 - It is also necessary that a self-moving being be divisible and have parts, since, as it is proved in the Physics [VI, 4], whatever is moved is divisible.

Hmmm. I think by this, he is making a comparison between an immaterial reality, such as an angel or God, and a material reality. Basically between composite and non composite entities. Here, I think he would bring in the idea of material cause and formal cause as the most fundamental form of such divisibility.

Anyway, I’d like to hear your thoughts on these points. I’ll move on to paragraph 6 next where he starts to use points 5.2 and 5.2.1 in a proof.

God bless,
Ut

 

[utunumsint]

Paragraph 6 [6] On the basis of these suppositions Aristotle argues as follows.

Right, so points 5.1, 5.2, 5.2.1 and 5.3 are going to be deployed here and in the next paragraph 7. Seems that 5.2 and 5.2.1 are his starting point

That which is held to be moved by itself is primarily moved. [Point 5.2]
Hence, when one of its parts is at rest, the whole is then at rest. For if, while one part was at rest, another part in it were moved, then the whole itself would not be primarily moved; it would be that part in it which is moved while another part is at rest.

I think this is helping me understand what he means in 5.2. By primarily moved, he means altogether, not in a dependent sequence.

But nothing that is at rest because something else is at rest is moved by itself; for that being whose rest follows upon the rest of another must have its motion follow upon the motion of another. It is thus not moved by itself. [Point 5.2.1]

Ugg… seems fairly self evident. It a self mover cannot have parts, and its motion must occur together, then it can’t be moved by a resting part of itself, but must be moved by a moving part of itself. But then there were be a division in the entity. You could restate this that there would be a part of the entity that actualizes another part of the entity that is in potential.

Therefore, that which was posited as being moved by itself is not moved by itself. Consequently, everything that is moved must be moved by another. [Point 5.2.1]

OK. Well, he deals with some objects in paragraph 7 where perhaps he will help us unpack these statements and conclusions.

God bless,
Ut

 

[Blue_Horizon]

At this frozen instant, is there a reason that the rock is accelerating? And if so, what is that reason? No appeals to prior moments are allowed.

I am not pursuing this line with you Balto because it is inherently logically contradictory as I have prev stated. “At a frozen instant” there is no observable motion, no locomotive causality to be inferred and no agent to be seen." These things are only observed and inferred by comparing successive instants which you have disallowed. You are simply trying to square the circle, turn Physics into Metaphysics and essentially are asking me a “have you stopped beating your wife” type question which forces me to acknowledge an assumption whatever response I give .

Well you seem to have defined cause and effect in such a way that it necessitates that causes and effects be temporally separated.

I am simply trying to communicate what I see observed Physical Reality doing.

Do you accept that even in the hand ball example start time and end time differ wrt the chain of locomotive cause/effects? Even Linus accepts this. Even Feser seems open to this where he states such chains need not be simultaneous.
Why don’t you?

And if a chain of locomotive causality has a starting time and a finishing time that differ then that conclusion follows as a matter of logic that chains of locomotive cause and effect are time sequential.

Originally Posted by Blue Horizon View Post
Please supply a clear example of a chain of locomotion where cause and effect are not temporally separated.

Then we have nothing further to discuss on this particular thread though its an interesting position you take here. Aristotle and Aquinas obviously believe this is change.

It doesn’t matter if it is accidental or substantial change, both are real and worthy of the single name “change” in their systems. If you cannot accept this then you must accept that you do not accept the coherence of their philosophic systems.
If that is the case on what basis do you argue using their philosophic concepts and terminology?

You need to refute them on their own terms.

If you don’t accept that uniform velocity is valid change maybe this applies to you more than me?

Until you are willing to accept this postulate of Aristotle I simply cannot discuss this thread topic further with you because you are inherently involved in a contradiction if you want to use some of their philosophic vocab but not others. Its a coherent vocab, if you do not accept their definition of “change” then there is going to be something implicitly misleading in your application of their four causes and hence cause/effect.

Which does seem to be the case.

 

[Blue_Horizon]

Right, but do you agree that this process can be over time? The way I understand it is that all that needs to be simultaneous is that the initial cause that starts the per se causal chain needs to be in existence as the source of the action that moves the entire instrumental chain. If that initial cause were to go out of existence, say half way through the execution of the causal chain, then the remainder of that uninstantiated causal chain would not be moved.

Using the example you mentioned to Blue:

I would say that the immediate cause of the rock moving (or at least in the initial accelerating) is the stick. The stick (with an artificially imposed final cause of moving rocks) immediately moved the rock, but the motion of the stick was caused by a temporally earlier cause and effect transaction between the motion of the hand and the motion of the stick, that was cause by an earlier cause and effect transaction between the motor neurons that triggered the muscles to contract, which was caused by processes in the brain, etc…

What do yo think? The only thing that need be simulateous in this description, in terms of the entire sequence of actions and the end goal of moving the rock, is the existence of the initial mover, and all the instrumental causes in between, and the rock that moves, even though the events may be spread out over time.

God bless,
Ut

This sounds fair to me.
And the initial agent must always be of a different order (eg one with a soul) than the remaining chain of agents involved in local motion.

 

[Blue_Horizon]

I agree with this also. This illustrates why quibbling over scientific details is missing the point. The whole point of the rock and staff example is to get someone to think of the series of instrumental causes and the existence of the unmoved first mover in this causal chain. We’re not trying to make a scientific point, but a metaphysical one. If the point we are making is wrong, then things can change themselves spontaneously for no reason. I don’t know of anyone who wants to accept that.

The point is that some philosopher’s here have been trying to say that chains of locomotive causality are “simultaneous.”

This to me is a palpable nonsense. If that is so either our scientific instruments are wrong or the metaphysic principle is wrong or it has been misapplied to the case in question.

It is pretty obvious to me, and it appears, to UUS, Linus and even Feser, that such is not the case with chains of locomotive causality despite appearances.

It is a case of a misapplication of a valid metaphysic principle to physical reality.

 

[utunumsint]

I was just thinking, would principle 5.1 immediately rule out locomotion and an instance of an entity that is self moved?

Point 5.1 If something moves itself, it must have within itself the principle of its own motion; otherwise, it is clearly moved by another.

I mean, we may say that an entity has by nature the tendency to remain at rest or in motion after it has been put in rest or in motion, but that in no way implies it being self moved.

God bless,
Ut

 

[Blue_Horizon]

Some thoughts on motion or change in Aquinas and Newton

One source I see here between the apparent contradiction which has been a part of the discussion of this thread between Newton’s first law of motion and motion as defined by Aristotle and followed by Aquinas is that according to Newton’s law of inertia a body in motion will persist in uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it. Fundamentally, such a body in uniform motion in a straight line is not changing and as such this is equivalent for Aristotle/Aquinas I believe that it is not in motion.

I like the logical approach Richca but I don’t think this is the solution to the conundrum.
I don’t see how Aristotle would ever say that any sort of locomotion (uniform or otherwise) could not be demonstrating change. Because for him its really about place not locomotion.

Even uniform motion inherently involves a change of place.
That’s an accidental change, there’s no way around it.

I believe the solution, wrt the First Way, is to correctly identify whether “change in place” always requires an efficient mover according to Aristotle?

I believe it doesn’t if we translate his quid movetur principle appropriately to context.
His principle, I believe, only applies to “setting something in motion” and not to its “continuing in motion” - UNLESS that continuance be acceleration.

This understanding is fully reconcilable with Newton’s 1st Law.

Both Newton and Aristotle/Aquinas agree that a change requires an external mover for whatever is changing is changed by another.

No. Your interpretation of this principle is problematic.
As explained above only “what is set in motion” requires another, the ongoing change of place consequent may not require the continuing presence of another in the same way.
That is how I read Aristotle, I don’t know enough about Newton’s terminology to know how he understands Aristotle on this principle.

A body in motion such as a heavenly body is of course a case of local motion.

But what sort of local motion are you assuming … uniform velocity or not? It makes a big difference for understanding Newton on this point.