Aquinas' Third Way

[seeker_of_God]

I’ve been studying Aquinas’ third way for proving the existence of God, based on the contingency of things and the necessity of a being that exists necessarily.

I have studied it in as much detail as I could in the midst of other things, and the more I do, the weaker it seems to me.

Here are my issues. I would be very curious to see your refutations, or point out why my issues might not be problematic after all.

The first is more unstable, but still something. Why must there be only one being that exists necessarily? Aquinas says that there are contingent things, and in order for contingent things to exist, there must then be a necessary being. But he does not say that all other things besides this necessary being are contingent. Why can there only be one non-contingent being?

The second is more stable in my mind. The assumption is that the necessary being, viz. God, was never generated, and will never “corrupt” to use Aquinas’ terminology. He says, though, that there are things in the world that are possible not to be, because they are generated, or corrupt. He never says that all things must both be generated and corrupt. Indeed, if one believes in the soul, such is generated, but never corrupts. Why could there not be a being that was never generated, yet corrupts? This would satisfy the requirement of a being that was never created, yet it would not always have to exist.

Simply:
If A creates B, A only has to exist up to the time that it creates B. Then A’s existence has no affect on B at all. We see this in the natural world. When Michelangelo painted his paintings, they were not dependent on his existence in the natural world, or else they would have immediately ceased to exist upon his death. Obviously this is not the case.

Please note carefully that I do believe in God. But this is philosophy and I lay my assumptions aside to treat this argument fairly, and I hope everyone else can do the same.

 

[buffgbob]

Excuse me if I am simplifying this too much.

Basically, everything which is corruptible will cease to exist (if it relies on its own power). Now, a necessary being necessarily exists so it cannot possibly cease to exist. Hence, it cannot be corruptible.

Another way of looking at it is by applying a pseudo time to God. If we assume God is corruptible, then time applies to God for He can be an admixture of potentiality and actuality. Since God has no beginning, if He were corruptible it stands He would cease to exist before He was able to create anything (as there would be infinite time before the date of His creation and not an infinite power to sustain Him in His corruptible state).

 

[seeker_of_God]

Excuse me if I am simplifying this too much.

Basically, everything which is corruptible will cease to exist (if it relies on its own power). Now, a necessary being necessarily exists so it cannot possibly cease to exist. Hence, it cannot be corruptible.

Please define “relies on its own power.” How can a rock rely on its own power? Yet it continues to exist, and at some point corrupts and ceases to exist.

Well we haven’t yet proven a necessary being is actually, well, necessary, so to speak. I am saying that all that is required for things to exist is that there is a being who was never generated, yet at some point may cease to exist.

 

[seeker_of_God]

Another way of looking at it is by applying a pseudo time to God. If we assume God is corruptible, then time applies to God for He can be an admixture of potentiality and actuality. Since God has no beginning, if He were corruptible it stands He would cease to exist before He was able to create anything (as there would be infinite time before the date of His creation and not an infinite power to sustain Him in His corruptible state).

You edited your post while I was replying.

This point deserves consideration. You may have a point, but I will have to consider it.

Can you please clarify what you mean by there not being an infinite power to “sustain Him in his corruptable state”?

Edited to add: I’d also love if some atheists/agnostics would like to refute the points brought up in this thread just so I can see different sides to this.

 

[buffgbob]

You are correct in saying a rock has no power. It is corruptible and naturally will cease to exist. Such is true of all corruptible things. However, there is an obvious exception in Christian truth to this: we say we have immortal souls. However, we say we have immortal souls because of God’s infinite power to sustain our souls forever. That is the reason I discuss the necessity for a corruptible thing to have a power preventing it from becoming corrupt.

Now there are two scenarios here. If God does naturally becomes corrupted, he is corruptible and will be corrupted. In order to last an infinite time, he would need an infinite power to sustain Himself (and oppose nature) in a corruptible state. However, all things desire their own perfection. If God has an infinite power, he would use it to make Himself infinite. If he does not become naturally corrupted he is not corruptible and will not be corrupted. However these things are interdependent. The only way a thing can be not corruptible is if it were pure act (no potentiality). It also follows that this thing has infinite power.

 

[seeker_of_God]

You are correct in saying a rock has no power. It is corruptible and naturally will cease to exist. Such is true of all corruptible things. However, there is an obvious exception in Christian truth to this: we say we have immortal souls. However, we say we have immortal souls because of God’s infinite power to sustain our souls forever. That is the reason I discuss the necessity for a corruptible thing to have a power preventing it from becoming corrupt.

Now there are two scenarios here. If God does naturally becomes corrupted, he is corruptible and will be corrupted. In order to last an infinite time, he would need an infinite power to sustain Himself (and oppose nature) in a corruptible state. However, all things desire their own perfection. If God has an infinite power, he would use it to make Himself infinite. If he does not become naturally corrupted he is not corruptible and will not be corrupted. However these things are interdependent. The only way a thing can be not corruptible is if it were pure act (no potentiality). It also follows that this thing has infinite power.

Thank you. This really makes me think. Is this about infinite power sustaining our soul knowable through reason, or is it a matter of faith? It certainly makes logical sense at least.

So through this we come to see that God is changeless (no potentiality, as you say), and necessarily infinite in power. This makes things more clear for me.

Because He is changeless, it would also reveal to me the reason He is outside time.

And it clarifies part of the meaning of the Prime Mover. If God is pure actuality, then it could be said that He is the first to bring a thing from potentiality into actuality? He does not change, but can cause change, namely creation, to occur.

Anyway this greatly clarifies things for me on this matter, and I thank you.

 

[buffgbob]

If you want to look at Aquinas proof of God’s existence, I recommend reading the Summa Contra Gentiles instead. It can be found here:

op-stjoseph.org/Students/study/thomas/ContraGentiles.htm

Particularly on his “Five Ways” they are clarified more fully.

 

[Betterave]

Why must there be only one being that exists necessarily? Aquinas says that there are contingent things, and in order for contingent things to exist, there must then be a necessary being. But he does not say that all other things besides this necessary being are contingent. Why can there only be one non-contingent being?

But Aquinas does not say that there can be only one non-contingent (necessary) being. He says that every necessary being must have its necessity caused by another, or not [caused by another]. And not all necessary beings can fall into the first category, so there must be a necessary being whose necessity is uncaused.

The second is more stable in my mind. The assumption is that the necessary being, viz. God, was never generated, and will never “corrupt” to use Aquinas’ terminology. He says, though, that there are things in the world that are possible not to be, because they are generated, or corrupt. He never says that all things must both be generated and corrupt. Indeed, if one believes in the soul, such is generated, but never corrupts. Why could there not be a being that was never generated, yet corrupts? This would satisfy the requirement of a being that was never created, yet it would not always have to exist.

Simply:
If A creates B, A only has to exist up to the time that it creates B. Then A’s existence has no affect on B at all. We see this in the natural world. When Michelangelo painted his paintings, they were not dependent on his existence in the natural world, or else they would have immediately ceased to exist upon his death. Obviously this is not the case.

One way of understanding this is to understand that if A creates B out of nothing, B is made of nothing except what it receives from A, so its subsistence never ceases to depend on A (there is nothing else it can depend on). If M paints P out of pre-existing materials, P is made of pre-existing materials, with their own power of subsisting independently of M, and which receive a particular form from M, also with its own power of subsisting materially, independently of M.

 

[Kamalayka]

The first is more unstable, but still something. Why must there be only one being that exists necessarily? Aquinas says that there are contingent things, and in order for contingent things to exist, there must then be a necessary being. But he does not say that all other things besides this necessary being are contingent. Why can there only be one non-contingent being?
.

(First we have to remember that God is eternally beyond our comprehension)

After thinking about it for several years, it just seems to make sense that only One God would exist.

I am not very good with explaining concepts, but the best way I can think of to word it is like this:

An attribute of God is the NECESSITY TO EXIST.

First, as Christians, we assume God exists. We also assume that God cannot “not” exist. He is the only absolute “Necessity.”

He is all-knowing, all-present, all-powerful, and all-loving, and because He is these things, **there would be no “need” for 2 or more Gods. **

One God “suffices” in other words (if that makes sense).

I am not good with words, and I have a hard time communicating concepts in my head. This is the best way I can explain my view on this. Hope it helps. ​

If God is all that is absolutely necessary and that has to exist, there would be no need for two or more of Him;
a second All-Powerful God would be beyond “necessity” so to speak.

Why?

Because anything that is beyond what is necessary is not necessary, which is an attribute of God.​

Another angle to look at this:

Why a theoretical “Second God” could not be God:

Imagine that there is a second all-powerful God. This second God would automatically be a “non-God,” by virtue of the fact that He exists along side God (that already is).

He would be lacking in the attribute of necessity, making Him not a God anyways!

 

[seeker_of_God]

(First we have to remember that God is eternally beyond our comprehension)

After thinking about it for several years, it just seems to make sense that only One God would exist.

I am not very good with explaining concepts, but the best way I can think of to word it is like this:

An attribute of God is the NECESSITY TO EXIST.

First, as Christians, we assume God exists. We also assume that God cannot “not” exist. He is the only absolute “Necessity.”

He is all-knowing, all-present, all-powerful, and all-loving, and because He is these things, **there would be no “need” for 2 or more Gods. **

One God “suffices” in other words (if that makes sense).

I am not good with words, and I have a hard time communicating concepts in my head. This is the best way I can explain my view on this. Hope it helps. ​

If God is all that is absolutely necessary and that has to exist, there would be no need for two or more of Him;
a second All-Powerful God would be beyond “necessity” so to speak.

Why?

Because anything that is beyond what is necessary is not necessary, which is an attribute of God.​

Another angle to look at this:

Why a theoretical “Second God” could not be God:

Imagine that there is a second all-powerful God. This second God would automatically be a “non-God,” by virtue of the fact that He exists along side God (that already is).

He would be lacking in the attribute of necessity, making Him not a God anyways!

Kamalayka,

While I might agree with you theologically, given we are discussing philosophy, we cannot take this as an assumption. “Make sense” doesn’t really work in philosophy.

This proof says nothing about God being all-powerful, all-knowing, all-loving, etc, so that doesn’t suffice as a philosophical reason for there only being one. Actually the fourth argument might say something about Him being absolute perfection, but that’s about as far as it goes. These arguments discuss Him as the Prime Mover, First Efficient Cause, Necessary Being, the Cause of all being and perfection, and
Intelligent Being that leads non-intelligent beings to their ends.

In studying philosophy, I don’t want my theological beliefs to bias me in my reasoning in philosophy.

By necessity, all that is meant is that it is in God’s nature to exist, but doesn’t say anything about that existence.

The point brought up earlier about needing infinite power to exist infinitely could be a reason why there cannot be two beings that exist necessarily, though, I think. Or the fact that God is pure actuality.

 

[buffgbob]

Yes, the proper order of understanding is first that unmoved mover(s) must exist necessarily. Then he discusses why an unmoved mover must exist in a certain way. Aquinas doesn’t prove God is “one” until much later, after all.

(Your question earlier was why can’t something be corruptible and be the unmoved mover, which is really not something discussed in this proof. In this proof he discusses why there must be an unmoved mover, later he discusses why this thing must be pure act.)

 

[seeker_of_God]

Yes, the proper order of understanding is first that unmoved mover(s) must exist necessarily. Then he discusses why an unmoved mover must exist in a certain way. Aquinas doesn’t prove God is “one” until much later, after all.

(Your question earlier was why can’t something be corruptible and be the unmoved mover, which is really not something discussed in this proof. In this proof he discusses why there must be an unmoved mover, later he discusses why this thing must be pure act.)

That is a fair point. Aquinas only says that there must be a being who does not receive its necessity from another, but causes others to have necessity.