Aquinas' First Way and Principle of Sufficient Reason

[NowAgnostic]

Two questions on Aquinas’ First Way (argument from motion), spinning off from the PSR thread.

I accept the definition of motion as reduction of potentiality to act, and that nothing can move itself. I’ll tentatively accept that there cannot be an infinite regression in an essentially subordinated series of causes (I have not seen a logical proof of this though, if someone would like to furnish one please go ahead).

Let’s say B moves A from potency to act in some respect in which B is already in act. The argument (in the case of an essentially ordered series) is that B must be caused to move A by some other agent C. Then, C must be caused to move B to move A by agent D, and so on. This is to be distinguished from asking how B got into act in the relevant respect in the first place, saying it must have been brought there by C at some point in the past, C must have been brought there by D further in the past, and so on. This would only be an accidentally subordinated series (C’s action only causes B’s coming into act, but not A’s). This is not Aquinas’ argument for his is based upon an essentially ordered series (other versions of the Cosmological Argument argue against the possibility of an accidentally ordered infinite regress but this is not relevant here).

First question: doesn’t the argument use the Principle of Sufficient Reason, even if it isn’t stated explicitly as such? B moving A cannot be just a brute fact without explanation otherwise the argument never gets off the ground. Now perhaps it can be clarified that before B moves A, B is only potentially a mover of A, and after C’s action the potentiality is actualized, making B an actual mover of A. At least you need a form of the PSR which states that potentialities don’t actualize without explanation, and to me that IS the PSR (explaining why this potentiality rather than that is actualized is the same is explaining why this contingent fact rather than that is true). As will be seen, the PSR principle that “nothing exists without an explanation” is necessary as well.

Second question: How can it be concluded that the first mover in such a series is a purely actual being (God) acting contingently without special pleading or equivocation on the meaning of “act”? I’ll pose the second part of the question first. Now by definition if there must always be an external cause for one being moving another the series must go on to infinity. But the PSR does not demand a cause, only an explanation, and an epistemically possible explanation is that at the end of the chain Z is moving Y not because Z was moved by something else, but because it is logically necessary that Z move Y because of Z’s own nature, itself also logically necessary. And, obviously, what is logically necessary cannot change, so Z’s will to move Y is fixed in eternity. But this would make all motion logically necessary, a conclusion which proponents of the First Way won’t accept. However if the implicit premise “nothing moves another without a sufficient explanation” is abandoned only when an unpalatable conclusion is reached, that’s special pleading.

Now, it will be urged that the premise “nothing moves another without a sufficient explanation” only applies to those movers changed from potentially moving another to actually moving another, but in the case of God, He is pure act, from eternity, there never “was” any potentiality in Him. But then why does the first mover have to be purely actual, not just actual in the respect of what is being reduced from potentiality to act? I can postulate an eternally existent entity (or group of them for that matter), not purely actual in every respect, but actual in the necessary respect to produce the observed motion. Note that they were always in act in the necessary respect from eternity, there never “was” any potentiality in the relevant respect in them either. These are not logically impossible entities in this framework (Aquinas himself thought an eternal universe was possible). It will be asked what explanation can be given for their existence, though. And I will respond by asking what explanation can be given for God’s existence. If it is argued that He is logically necessary as “pure act” then that “act” is also being in act in the sense of being a mover, as argued above to avoid demanding an explanation for His being mover, and that this makes being a mover also logically necessary. There is an equivocation on “act” - “act” as being, or “act” as mover.

 

[Eucharisted]

God is motion itself, philosophically speaking. Motion moves itself. God is only called the First Mover because this title has two significent meanings: It notes that God is a being and not a thing and it notes that God is before all things and He moves Himself.

 

[James_S_Saint]

Perhaps for a different time and thread, but in reality, “things don’t move”. That probably sounds absurd, but with explanation, you can see the truth of it. Waves in water is a limited example in that they do not push each other, nor do they “move”. They get reformed in front of where they were and merely combine rather than push. They are merely the height of the average position of the water. They are not exactly “things”. All proposed “things” are in reality this same way (matter is but a specific arrangement of energy).

As long as you are thinking in terms of things moving and being moved, you will always be in confusion.

 

[punkforchrist]

There are a lot of questions here! I’ll stick to answering just a few. Others, I’m sure, will chime in.

NowAgnostic:

First question: doesn’t the argument use the Principle of Sufficient Reason, even if it isn’t stated explicitly as such? B moving A cannot be just a brute fact without explanation otherwise the argument never gets off the ground. Now perhaps it can be clarified that before B moves A, B is only potentially a mover of A, and after C’s action the potentiality is actualized, making B an actual mover of A. At least you need a form of the PSR which states that potentialities don’t actualize without explanation, and to me that IS the PSR (explaining why this potentiality rather than that is actualized is the same is explaining why this contingent fact rather than that is true).

The PSR demands that there be some logically necessary reason for some thing X. If, however, we substitute “motion” for X, and motion is not logically necessary (motion need not exist in every possible world), then it follows that a logically necessary explanation need not be given for motion. The only requirement is that there is a metaphysically necessary explanation (the First Mover) in every world in which motion exists. Given that motion exists in this world, it follows that a First Mover exists.

I accept the definition of motion as reduction of potentiality to act, and that nothing can move itself. I’ll tentatively accept that there cannot be an infinite regression in an essentially subordinated series of causes (I have not seen a logical proof of this though, if someone would like to furnish one please go ahead).

In several threads, I’ve offered the following analogy to illustrate the impossibility of an infinite regress of essentially ordered causes (movers). Imagine an eternally existent watch. No matter how many gears there are, even infinitely-many, none of them will move apart from the cause of motion found in the spring. What this demonstrates is that a first member of a series of essentially-ordered movers is necessary to bring about the cause of the set. Applied to the motion of the celestial bodies, or the laws of nature, we can therefore postulate the existence of a First Mover.

Your second question incorporates the assumption that the prima via relies upon the PSR. I maintain that it doesn’t.

Now, it will be urged that the premise “nothing moves another without a sufficient explanation” only applies to those movers changed from potentially moving another to actually moving another, but in the case of God, He is pure act, from eternity, there never “was” any potentiality in Him. But then why does the first mover have to be purely actual, not just actual in the respect of what is being reduced from potentiality to act?

This is a great question. Let’s make it a little more concrete. If there must be a First Mover with respect to some actuality, say intelligence, why does this First Mover have to be Pure Act with respect to every actuality (power, goodness, etc.)? The answer to this has to do with the First Mover’s existence and essence being identical.

What, for example, is the difference between a real unicorn and an imaginary one? The answer to this is that the former possesses existence, whereas the latter does not. If, then, each thing receives its existence from another, then there would be an infinite regress of movers, which is impossible. As a result, the First Mover must possess its existence essentially. Now, since every actuality is something existent (that what it means for something to be actual), each actualized potentiality must be moved by a First Mover that is Pure Act.

 

[NowAgnostic]

There are a lot of questions here! I’ll stick to answering just a few. Others, I’m sure, will chime in.

OK, yes I know I have a lot of questions.

The PSR demands that there be some logically necessary reason for some thing X.

No, then X would be logically necessary also. The PSR only demands some reason for some logically contingent thing X. A sufficient reason for rain is evaporation then condensation of water. The PSR does not say evaporation and condensation are logically necessary.

If, however, we substitute “motion” for X, and motion is not logically necessary (motion need not exist in every possible world), then it follows that a logically necessary explanation need not be given for motion.

See above. The PSR only demands some explanation for motion.

The only requirement is that there is a metaphysically necessary explanation (the First Mover) in every world in which motion exists. Given that motion exists in this world, it follows that a First Mover exists.

OK, now I’m getting really confused. Are you suggesting the First Mover is not a logically necessary being but merely a metaphysically necessary one?

In several threads, I’ve offered the following analogy to illustrate the impossibility of an infinite regress of essentially ordered causes (movers). Imagine an eternally existent watch. No matter how many gears there are, even infinitely-many, none of them will move apart from the cause of motion found in the spring. What this demonstrates is that a first member of a series of essentially-ordered movers is necessary to bring about the cause of the set. Applied to the motion of the celestial bodies, or the laws of nature, we can therefore postulate the existence of a First Mover.

I’m wondering if you could do better than attempting to argue from analogy and the laws of nature. Because, without friction, there needs to be no wound-up spring for the watch to move, and the infinite set of gears can be eternally in motion. Can you give a logical argument? That would help. I admit an infinite essentially subordinated regress seems weird, but is there a logical argument to be had?

Your second question incorporates the assumption that the prima via relies upon the PSR. I maintain that it doesn’t.

Then no explanation or reason need be given for a potentiality becoming actual, and the First Way falls apart. Why does A move from potency to act? It can just happen without explanation, if the PSR is false. If the PSR says “nothing happens without an explanation” then certainly motion demands one. Could you state your version of the PSR and why the First Way doesn’t need it?

This is a great question. Let’s make it a little more concrete. If there must be a First Mover with respect to some actuality, say intelligence, why does this First Mover have to be Pure Act with respect to every actuality (power, goodness, etc.)? The answer to this has to do with the First Mover’s existence and essence being identical.

And why must the First Mover’s existence and essence be identical? This must be proven.

What, for example, is the difference between a real unicorn and an imaginary one? The answer to this is that the former possesses existence, whereas the latter does not. If, then, each thing receives its existence from another, then there would be an infinite regress of movers, which is impossible.

Are you applying this argument to an accidentally subordinated regress or an essentially subordinated one? Many, including Aquinas himself, thought an infinite accidentally subordinated regress was possible. He could imagine, for instance, a sequence of parents going on to infinity, because a man does not generate a son just because he is the son of a man. And I can imagine the earth going around the sun forever. But in an essentially subordinated series it means that B is formerly in potentiality with respect to moving A but is moved to act (actually moving A) by C. Do you agree with this?

As a result, the First Mover must possess its existence essentially.

Now, since every actuality is something existent (that what it means for something to be actual), each actualized potentiality must be moved by a First Mover that is Pure Act.

This does not follow. The fact that something did not receive its existence from another does not imply it must necessarily exist (or exist essentially as you say). I’m confused again here BTW, because we are now talking about logically (not merely metaphysically) necessary existence. Unless you use the PSR and deny its existence can be an unexplained brute fact. Let me explain the horns of the dilemma.

1. Deny that any actuality can be an unexplained brute fact. But then when you get to the First Mover, it is in act with respect to moving the next entity. Every actuality is something existent, and in the case of the Prime Mover, is necessary. And you can’t distinguish “act” in the sense of existence from “act” in the sense of being a mover, in the case of a being which is pure act. Even if you could, you could still not have the act of being a mover as an unexplained brute fact, which means it must be logically necessary, as there is no other mover to move God, just like there’s no other creator to create God.
2. Admit that an actuality can be an unexplained brute fact, but then the existence of a first mover can be an unexplained brute fact also.

 

[Areopagite]

(Responding to: The PSR demands that there be some logically necessary reason for some thing X.)

No, then X would be logically necessary also. The PSR only demands some reason for some logically contingent thing X. A sufficient reason for rain is evaporation then condensation of water. The PSR does not say evaporation and condensation are logically necessary.

I’m sorry to bring this up again, especially if I’m wrong … but you seem to be mixing up absolute necessity and necessity by suppositum. You see, if someone is sitting on a chair, then logical necessity demands (by suppositum) that the chair exist. But this is not the same as saying that it was absolutely necessary that one sit on the chair. That is the kind of thing you seem to be mixing up. But I may be misinterpreting the matter. I mentioned some of this on a previous post, with some Aquinas quotes here:

forums.catholic-questions.org/showpost.php?p=5730189&postcount=35

Why does A move from potency to act? It can just happen without explanation, if the PSR is false. If the PSR says “nothing happens without an explanation” then certainly motion demands one.

I may be taking this out of context too much, but … if things can happen without explanation … then anything’s fair game, right? Why stop at possibly eternally existing things … what about (hypothetically) things that just pop into existence for no reason? If the PSR is false, there would be no problem with that. What if the laws of physics stop working or change drastically … for no reason! Since the PSR is vacant from its throne, such things are not illegal … or rather, they are not irrational. Things could exist and happen for no reason, and no one can complain.

Am I out in left field here? I might be.

And why must the First Mover’s existence and essence be identical? This must be proven.

If indeed an absolute necessary being exists that brings contingent things into existence, the only way a thing could be absolutely necessary is that if it exists by nature … that is, if existence was part of everything that made up that necessary being. Something like this, I believe. Because if something doesn’t exist by its very essence, it’s contingent.

1. Deny that any actuality can be an unexplained brute fact. But then when you get to the First Mover, it is in act with respect to moving the next entity. Every actuality is something existent, and in the case of the Prime Mover, is necessary. And you can’t distinguish “act” in the sense of existence from “act” in the sense of being a mover, in the case of a being which is pure act. Even if you could, you could still not have the act of being a mover as an unexplained brute fact, which means it must be logically necessary, as there is no other mover to move God, just like there’s no other creator to create God.
2. Admit that an actuality can be an unexplained brute fact, but then the existence of a first mover can be an unexplained brute fact also.

This problem, I think, is not a problem if God’s essence and existence are the same. I may be wrong, though. This is because God’s existence would be not be an unexplained brute fact but explained by His essence being identical to His existence.

 

[punkforchrist]

NowAgnostic:

OK, yes I know I have a lot of questions.

Nothing wrong with that!

No, then X would be logically necessary also. The PSR only demands some reason for some logically contingent thing X. A sufficient reason for rain is evaporation then condensation of water. The PSR does not say evaporation and condensation are logically necessary.

The PSR applies to a necessary being, too. I’ll define the PSR below.

See above. The PSR only demands some explanation for motion.

Motion isn’t logically necessary, so whatever explains motion need not be logically necessary.

OK, now I’m getting really confused. Are you suggesting the First Mover is not a logically necessary being but merely a metaphysically necessary one?

The First Way concludes that the First Mover is metaphysically necessary, but is silent on whether it is logically necessary. One would have to supplement the First Way with the PSR, or the Ontological Argument, or something else in order to conclude that a logically necessary being (God) exists.

I’m wondering if you could do better than attempting to argue from analogy and the laws of nature. Because, without friction, there needs to be no wound-up spring for the watch to move, and the infinite set of gears can be eternally in motion.

We would also have to get rid of gravity, since moving objects attract each other. In any case, I’m suggesting neither that friction nor the First Mover are logically necessary. The analogy I have provides inductive support for the existence of a First Mover. Our observations tells us that a first member of a set of efficiently-ordered causes is required in order for the set to cause anything at all.

Can you give a logical argument? That would help. I admit an infinite essentially subordinated regress seems weird, but is there a logical argument to be had?

Thomas does provide two additional arguments, however. I’ll present one of them here. If there were an infinite series of movers, then they would be moving something within a finite period of time. However, it would take infinite time for an infinite series to move anything all. Therefore, the series (or hierarchy) of movers must be finite and be grounded in a First Mover.

Then no explanation or reason need be given for a potentiality becoming actual, and the First Way falls apart. Why does A move from potency to act? It can just happen without explanation, if the PSR is false. If the PSR says “nothing happens without an explanation” then certainly motion demands one. Could you state your version of the PSR and why the First Way doesn’t need it?

I think the best formation of the PSR is this:

“Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.”

Given that motion is logically contingent, in those worlds without motion there would be nothing that the First Mover is moving. No First Mover is required where no motion exists. A necessary being on the PSR, on the other hand, is logically necessary. So, if the First Mover is logically contingent (but metaphysically necessary in worlds with motion), then it must be distinct from a logically necessary being.

And why must the First Mover’s existence and essence be identical? This must be proven.

If the First Mover’s existence and essence were distinct, it would derive its existence from some other essence. A thing that is not of its very essence to exist need not exist (tautology), in which case it must be actualized. But, the First Mover has no potentiality to be actualized, given that it is changeless.

Are you applying this argument to an accidentally subordinated regress or an essentially subordinated one? Many, including Aquinas himself, thought an infinite accidentally subordinated regress was possible. He could imagine, for instance, a sequence of parents going on to infinity, because a man does not generate a son just because he is the son of a man. And I can imagine the earth going around the sun forever. But in an essentially subordinated series it means that B is formerly in potentiality with respect to moving A but is moved to act (actually moving A) by C. Do you agree with this?

I disagree with Thomas that an accidentally-ordered regress could be infinite, but I’m assuming for the sake of argument that it can be. I, too, can at least envisage the earth revolving around the sun from all eternity (much like an eternal watch), but the sun’s mass is still moving the earth in order for the latter to revolve around the former.

This does not follow. The fact that something did not receive its existence from another does not imply it must necessarily exist (or exist essentially as you say). I’m confused again here BTW, because we are now talking about logically (not merely metaphysically) necessary existence.

No, I’m only saying that Pure Act must exist in those worlds where potentialities are actualized (i.e. motion). The actual world contains things in motion. These moving things derive their existence from some other essence. We can apply this until we end the regress at the First Mover, which receives its existence from no other essence. If it received its existence from another essence, it would be actualized, as I mentioned above.

Per the dilemma:

1. Deny that any actuality can be an unexplained brute fact. But then when you get to the First Mover, it is in act with respect to moving the next entity. Every actuality is something existent, and in the case of the Prime Mover, is necessary.

Right, but this necessity need only be metaphysical.

1. Admit that an actuality can be an unexplained brute fact, but then the existence of a first mover can be an unexplained brute fact also.

That’s Swinburne’s position. He reasons that a simple being is more likely to be uncaused than a complex being.

 

[NowAgnostic]

I’m sorry to bring this up again, especially if I’m wrong … but you seem to be mixing up absolute necessity and necessity by suppositum…

I don’t see where you get this from. Logical necessity is absolute necessity not necessity by suppositum.

I may be taking this out of context too much, but … if things can happen without explanation … then anything’s fair game, right? Why stop at possibly eternally existing things … what about (hypothetically) things that just pop into existence for no reason? If the PSR is false, there would be no problem with that. What if the laws of physics stop working or change drastically … for no reason! Since the PSR is vacant from its throne, such things are not illegal … or rather, they are not irrational. Things could exist and happen for no reason, and no one can complain.

Exactly, so take your pick, deny the PSR at some point, which means there is something that is unexplained, or uphold the PSR altogether, which leads to modal collapse.

If indeed an absolute necessary being exists that brings contingent things into existence, the only way a thing could be absolutely necessary is that if it exists by nature … that is, if existence was part of everything that made up that necessary being. Something like this, I believe. Because if something doesn’t exist by its very essence, it’s contingent.

This I don’t understand. An absolutely necessary being is a logically necessary being.

This problem, I think, is not a problem if God’s essence and existence are the same. I may be wrong, though. This is because God’s existence would be not be an unexplained brute fact but explained by His essence being identical to His existence.

And it would also be identical to his being First Mover, which would mean motion would be logically necessary.

 

[NowAgnostic]

Motion isn’t logically necessary, so whatever explains motion need not be logically necessary.

I’ll agree with that.

The First Way concludes that the First Mover is metaphysically necessary, but is silent on whether it is logically necessary. One would have to supplement the First Way with the PSR, or the Ontological Argument, or something else in order to conclude that a logically necessary being (God) exists.

OK. Then the First Way can’t prove God exists.

We would also have to get rid of gravity, since moving objects attract each other. In any case, I’m suggesting neither that friction nor the First Mover are logically necessary. The analogy I have provides inductive support for the existence of a First Mover. Our observations tells us that a first member of a set of efficiently-ordered causes is required in order for the set to cause anything at all.

I’m all for inductive support, and it’s what science is based on, but the First Way claims to be a metaphysical proof, not merely inductive evidence.

Thomas does provide two additional arguments, however. I’ll present one of them here. If there were an infinite series of movers, then they would be moving something within a finite period of time. However, it would take infinite time for an infinite series to move anything all. Therefore, the series (or hierarchy) of movers must be finite and be grounded in a First Mover.

Not necessarily if all the motion is occurring simultaneously. Infinity times zero is undefined. It could take infinite time, it could take finite time, it could take zero time.

I think the best formation of the PSR is this:

“Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.”

Is “necessity of its own nature” equivalent to logically necessary? If not, there is not an explanation of its existence - nothing logically entails it.

Given that motion is logically contingent, in those worlds without motion there would be nothing that the First Mover is moving. No First Mover is required where no motion exists. A necessary being on the PSR, on the other hand, is logically necessary. So, if the First Mover is logically contingent (but metaphysically necessary in worlds with motion), then it must be distinct from a logically necessary being.

A logically contingent, but uncaused, unentailed being has no explanation for its existence. It could not exist.

If the First Mover’s existence and essence were distinct, it would derive its existence from some other essence. A thing that is not of its very essence to exist need not exist (tautology), in which case it must be actualized. But, the First Mover has no potentiality to be actualized, given that it is changeless.

An entity whose essence is identical to existence must exist, assuming such an entity is logically possible. But, if the First Mover’s existence and essence are distinct, it need not exist logically speaking. I’m with you up to this point. But you’ve said that motion need not exist logically. Therefore, the First Mover need not exist logically. So, from this obviously the First Mover need not be a logically necessary being, so you cannot conclude its existence and essence are identical from the existence of motion alone.

Now, if we don’t have an infinite regress, not every actual entity can be an actualized potentiality. I’m sure you’ll agree with this. So there must be actual entities which exist either as brute fact, or by logical necessity.

No, I’m only saying that Pure Act must exist in those worlds where potentialities are actualized (i.e. motion). The actual world contains things in motion. These moving things derive their existence from some other essence. We can apply this until we end the regress at the First Mover, which receives its existence from no other essence. If it received its existence from another essence, it would be actualized, as I mentioned above.

Yes, and when you end it there, you end up with motion becoming logically necessary. The First Mover is in act with respect to its moving everything else, and this act did not come from any other essence, and this is the same act as its existence and essence. If the First Mover’s existence is logically necessary, so is its being the first mover and there being things in motion.

Right, but this necessity need only be metaphysical.

Yes, but when the metaphysically necessary being is Pure Act, essence identical to existence, it is also a logically necessary being. Because, the ontological proofs (the modal version being the simplest) show that if it is possible that a logically necessary being exists, it exists (necessarily). If you show that this being exists in our world, then you have proved its possibility and thus it exists necessarily.

 

[sillyfrog]

Thanks. I learned a lot from your responses.http://www.photosnag.com/img/4713/n09x0302vnsn/clear.gif

 

[punkforchrist]

NowAgnostic:

OK. Then the First Way can’t prove God exists.

It does state that in every world where motion exists, a First Mover must exist. So, given that motion exists in the actual world, there must be a First Mover in the actual world. None of this depends on the PSR and logical necessity.

I’m all for inductive support, and it’s what science is based on, but the First Way claims to be a metaphysical proof, not merely inductive evidence.

I disagree. Thomas explicitly mentions “induction” (Summa Contra Gentiles, ch. 13, paragraph 8) in support of the First Way.

Not necessarily if all the motion is occurring simultaneously. Infinity times zero is undefined. It could take infinite time, it could take finite time, it could take zero time.

Technically, it’s “infinity divided by zero is undefined”. You can multiply anything and get zero. In any case, the fact that motion could move simultaneously is not evidence that there could be an infinite regress of simultaneously moving movers.

Is “necessity of its own nature” equivalent to logically necessary? If not, there is not an explanation of its existence - nothing logically entails it.

Yes, the PSR entails the logical necessity of a necessary being.

A logically contingent, but uncaused, unentailed being has no explanation for its existence. It could not exist.

Yes, and the First Mover could be logically contingent via the First Way (the argument considered in and of itself).

An entity whose essence is identical to existence must exist, assuming such an entity is logically possible.

We could talk about the Ontological Argument at some point. For now, though, the First Way (all by itself) doesn’t mention an entity whose existence is identical with its essence. I agree that there is such a being, but that is an additional argument.

But, if the First Mover’s existence and essence are distinct, it need not exist logically speaking. I’m with you up to this point. But you’ve said that motion need not exist logically. Therefore, the First Mover need not exist logically. So, from this obviously the First Mover need not be a logically necessary being, so you cannot conclude its existence and essence are identical from the existence of motion alone.

Indeed, and I was talking about an additional argument at that point. Sorry for the confusion.

Now, if we don’t have an infinite regress, not every actual entity can be an actualized potentiality. I’m sure you’ll agree with this. So there must be actual entities which exist either as brute fact, or by logical necessity.

With possible worlds semantics, that must be the case. Of course, I don’t believe in brute facts (about things), but I don’t see how that entails that the First Way is dependent on the PSR.

Yes, and when you end it there, you end up with motion becoming logically necessary. The First Mover is in act with respect to its moving everything else, and this act did not come from any other essence, and this is the same act as its existence and essence. If the First Mover’s existence is logically necessary, so is its being the first mover and there being things in motion.

Consider a possible world without motion. I believe we can still argue that God exists in such a world; but, we cannot appeal to the First Way. The fact that the First Mover exists in all possible worlds implies neither that there is motion in all possible worlds, nor that the First Way attempts to demonstrate the existence of a logically necessary being.

Assuming that one essence is dependent on another, and this without motion, an additional argument must be used (the Ontological Argument, the Leibnizian Cosmological Argument, the Conceptualist Argument, etc.).

Yes, but when the metaphysically necessary being is Pure Act, essence identical to existence, it is also a logically necessary being. Because, the ontological proofs (the modal version being the simplest) show that if it is possible that a logically necessary being exists, it exists (necessarily). If you show that this being exists in our world, then you have proved its possibility and thus it exists necessarily.

I agree with that, but notice how this is an additional argument to the First Way.

 

[James_S_Saint]

Motion isn’t logically necessary, so whatever explains motion need not be logically necessary.

Actually motion truly is logically necessary in any world.

You cannot construct any 3 dimensional form wherein all free-to-move objects have a balance of force being applied to them. Nor can you have existence without imbalance of force.

Both of these conditions demand motion.

God is the logically necessary imbalance of force that brings about all existence.

 

[punkforchrist]

Hi James,

Aren’t you now assuming that space must be three-dimensional in every possible world? Why couldn’t there be a possible world with no physical entities - only God and abstract objects?
James S Saint:

God is the logically necessary imbalance of force that brings about all existence.

I’m not sure what an imbalance of force is, or why God is associated with it, but I agree that God is logically necessary to make sense of existence. God is logically necessary, but the First Way doesn’t attempt to establish that.

 

[NowAgnostic]

It does state that in every world where motion exists, a First Mover must exist. So, given that motion exists in the actual world, there must be a First Mover in the actual world. None of this depends on the PSR and logical necessity.

Fine, how do you get from the existence of a First Mover to the First Mover being God, or even that there is only one first mover for each chain of motion for that matter, without appealing at some point to the PSR. Don’t you demand an explanation for the motion or the existence of the movers?

I disagree. Thomas explicitly mentions “induction” (Summa Contra Gentiles, ch. 13, paragraph 8) in support of the First Way.

Yes, but there are other deductive proofs for what Aristotle is attempting to prove there.

Technically, it’s “infinity divided by zero is undefined”. You can multiply anything and get zero.

Been a while since you took calculus? (It’s OK.) But the limit of a times b as a goes to infinity and b goes to zero is undefined, depends on how you take the limits.

In any case, the fact that motion could move simultaneously is not evidence that there could be an infinite regress of simultaneously moving movers.

No, but it undercuts the argument that an infinite regress would take an infinite time.

Yes, the PSR entails the logical necessity of a necessary being.

Yes. It also entails however that that being’s actions are also logically necessary.

Yes, and the First Mover could be logically contingent via the First Way (the argument considered in and of itself).

Then if it could be logically contingent, it doesn’t need to be God. The first way is entirely consistent with a first mover being in act on one respect from eternity, but not in all. Its actuality was never in potency, it was in act from eternity, just like a purely actual first mover.

We could talk about the Ontological Argument at some point. For now, though, the First Way (all by itself) doesn’t mention an entity whose existence is identical with its essence. I agree that there is such a being, but that is an additional argument.

OK. If the First Way isn’t able to conclude that the first mover is purely actual, or an entity whose existence is identical to essence (philosophically speaking the two are equivalent) then it fails to show the existence of God. All it shows is that every chain of motion stops somewhere.

Indeed, and I was talking about an additional argument at that point. Sorry for the confusion.

No problem. This can be confusing stuff!

Consider a possible world without motion. I believe we can still argue that God exists in such a world; but, we cannot appeal to the First Way. The fact that the First Mover exists in all possible worlds implies neither that there is motion in all possible worlds, nor that the First Way attempts to demonstrate the existence of a logically necessary being.

Assuming that one essence is dependent on another, and this without motion, an additional argument must be used (the Ontological Argument, the Leibnizian Cosmological Argument, the Conceptualist Argument, etc.).

I do not see how you get to the first mover’s being God without using one of these arguments. You have to argue against a possible universe containing eternal contingent beings without a necessary being; for, if that universe is possible, motion can exist without God. Which would mean that the First Way is entirely irrelevant if it must be supplemented with an argument which would work (if it were sound) even without the existence of motion.

 

[punkforchrist]

NowAgnostic:

Fine, how do you get from the existence of a First Mover to the First Mover being God, or even that there is only one first mover for each chain of motion for that matter, without appealing at some point to the PSR.

The unity of the First Mover is usually addressed by any inference from First Mover to God. We could point to the “effects reflect their cause” maxim, in which case all power and knowledge that arises can be due only to the First Mover. As for whether it’s one or many, that too requires additional argumentation. One that doesn’t make use of “Pure Act” is our observation that whenever diverse things are ordered to one another, their order to one another results from something one. The order of an army is reducible to its general; and likewise, the order of moving entities is reducible to a single First Mover. If the unity of moving things came from diversity, they would have to intend one order insofar as they are diverse among themselves, which is impossible. After all, have you ever wondered how each moving entity participates in the singular attribute of intelligibility?

Don’t you demand an explanation for the motion or the existence of the movers?

I do, but that’s because I accept the PSR. However, that still doesn’t require any use of the PSR as we analyze the First Way in and of itself.

Yes, but there are other deductive proofs for what Aristotle is attempting to prove there.

That’s correct, but even if the deductive arguments fail (I believe they are sound), the inductive arguments may still hold up.

Been a while since you took calculus? (It’s OK.) But the limit of a times b as a goes to infinity and b goes to zero is undefined, depends on how you take the limits.

My understanding is that infinity times zero is zero, but I have heard others say it’s either “1” (this would imply a completed infinite, which is consistent under Cantorian axioms), or else “indeterminate”. We might say: given that 2 x 1/2 = 1, it follows that infinity x 1/infinity = 1. I think this is mistaken, though, given that infinity is a set, rather than an integer.

As far as limits go (via calculus), it is true that as n approaches infinity, then given 1/n, we get zero, and hence infinity times zero equals 1. Notice, though, that even given the multiplication of each fraction between 0 and 1, 0 and 1 are still the respective beginning and end of the set. So if there is any analogy, an infinite series of movers is still grounded in a First Mover.

Yes. It also entails however that that being’s actions are also logically necessary.

The S-PSR does, but if we allow for brute facts about states of affairs, the actions of a necessary being need not be necessary.

In sum, the First Way isn’t so ambitious that it attempts to demonstrate the divine attributes or the logical necessity of a First Mover. We can, however, argue that there is a First Mover, and that it possesses certain divine attributes without appealing to its logical necessity. My own attempt is in my first paragraph above.

 

[James_S_Saint]

Aren’t you now assuming that space must be three-dimensional in every possible world?

No. The 3D was just an “expression” from a particular example.

Why couldn’t there be a possible world with no physical entities - only God and abstract objects?

Because God IS the creator of the physical existence. If you have God, you have the physical creation instantly, just as pointed out in the “Before God??” thread. You cannot have one without instantly having the other.

I’m not sure what an imbalance of force is, or why God is associated with it,

Imbalance of force is what creates all motion and physical existence, also called “God”. Other than that, there is not a lot of direct association.

But continue as you were. I just popped in to point out a particular erroneous assumption being made, not to interrupt.

 

[Areopagite]

I don’t see where you get this from. Logical necessity is absolute necessity not necessity by suppositum.

Logical necessity includes both absolute necessity and necessity by suppositum. There isn’t just one kind of logical necessity. What is illogical about necessity by suppositum?

This I don’t understand. An absolutely necessary being is a logically necessary being.

Was I denying that? (maybe I was)

And it would also be identical to his being First Mover, which would mean motion would be logically necessary.

Just read Aquinas: newadvent.org/summa/1019.htm#article3

He discusses the issue “whether whatever God wills He wills necessarily” … maybe he’ll lay it down better than us non-angelic minds.

 

[itinerant1]

God is motion itself, philosophically speaking. Motion moves itself. God is only called the First Mover because this title has two significent meanings: It notes that God is a being and not a thing and it notes that God is before all things and He moves Himself.

How can the Unmoved Mover be “motion itself”? God is the immovable being. He is pure actuality and unchangeable; but motion involves change. James says, “Every good endowment and every perfect gift is from above, coming down from the Father of lights with whom there is no variation or shadow to change (1:17).” Clarify.

 

[itinerant1]

Perhaps for a different time and thread, but in reality, “things don’t move”. That probably sounds absurd, but with explanation, you can see the truth of it. Waves in water is a limited example in that they do not push each other, nor do they “move”. They get reformed in front of where they were and merely combine rather than push. They are merely the height of the average position of the water. They are not exactly “things”. All proposed “things” are in reality this same way (matter is but a specific arrangement of energy).

As long as you are thinking in terms of things moving and being moved, you will always be in confusion.

Well, it does sound absurd, just as you said. . “They get reformed”: reformation is a change and change necessarily involves movement or motion of some type. Water is a physical thing. So there are “things”, otherwise there would be nothing to talk about. Since water is a liquid it changes density, boundaries, and so on according to various physical influences.

Water is so subject to motion Heraclitus said, “You could not step twice into the same river; for other waters are ever flowing on to you.”

 

[itinerant1]

Now, it will be urged that the premise “nothing moves another without a sufficient explanation” only applies to those movers changed from potentially moving another to actually moving another, but in the case of God, He is pure act, from eternity, there never “was” any potentiality in Him. But then why does the first mover have to be purely actual, not just actual in the respect of what is being reduced from potentiality to act? I can postulate an eternally existent entity (or group of them for that matter), not purely actual in every respect, but actual in the necessary respect to produce the observed motion. Note that they were always in act in the necessary respect from eternity, there never “was” any potentiality in the relevant respect in them either. These are not logically impossible entities in this framework (Aquinas himself thought an eternal universe was possible). It will be asked what explanation can be given for their existence, though. And I will respond by asking what explanation can be given for God’s existence. If it is argued that He is logically necessary as “pure act” then that “act” is also being in act in the sense of being a mover, as argued above to avoid demanding an explanation for His being mover, and that this makes being a mover also logically necessary. There is an equivocation on “act” - “act” as being, or “act” as mover.

If a mover is just actual in what is being reduced from potency to act, that mover is not pure act and therefore has an admixture of potency in its being. Any being with an admixture of potency is a contingent being and does not exist of necessity. Hence the mover in this case must have its being from another. So, your scenario involves an infinite regress, which is impossible because there would then be no ultimate explanation for motion.

That is why a being who is pure act and moves without being moved is necessary to explain motion. This is true whether the universe is eternal or finite because we are not talking about a chain of movers extending back in time. Supposing the universe was eternal, always existed, it would still require an unmoved mover whose existence was necessary and outside of the universe to account for motion.

Typically, people misconstrue Aquinas’ argument by thinking if the universe is eternal there could be an infinite regress back in time and so his argument does not prove the existence of a necessary being or unmoved mover. However, this is to look at causality on a horizontal level, so to speak. Aquinas is speaking of causality in a vertical direction at each moment in time.

There is no equivocation on “act” when properly understood. A thing can move another only insofar as it is in act. A being cannot move itself in the same respect to that in which it is in act. One part, in act, must move another that is in potency to being moved. For example, an animal’s legs do not move themselves. The animal, rather, moves itself by means of its legs. God, on the other hand, who is pure actuality, can communicate being and motion to the universe of creatures without change or movement in himself. Our concept of God’s actuality is not univocal with the actuality of created things. It is analogical, and not equivocal. So we are talking about the analogy of being.