Help Please with Aristotle's Definition of Motion

[Geremia]

Aristotle defines motion in III, 1Phys. as “The fulfilment of what exists potentially, in so far as it exists potentially.” Expanding on this in III, 2In Phys., St. Thomas says:

1. As to the first, one must understand that some have defined motion by saying that motion is “a going-out from potency to act which is not sudden.” But they are found to be in error, because they have placed in the definition certain elements that are posterior to motion: for a “going-out” is a species of motion; “sudden,” likewise, involves time in its definition—the “sudden” is that which occurs in the indivisible of time *; time, however, is defined in terms of motion.
2. Consequently it is entirely impossible to define motion in terms of what is prior and better known otherwise than the Philosopher here does. For it has been pointed out already that every genus is divided by potency and act*. Now potency and act, since they are among the first differences of being, are naturally prior to motion, and it is these that the Philosopher uses to define motion.

Consider, therefore, that something is in act only, something is in potency only, something else is midway between potency and act. What is in potency only is not yet being moved; what is already in perfect act is not being moved but has already been moved. Consequently, that is being moved which is midway between pure potency and act, which is partly in potency and partly in act—as is evident in alteration. [or when water is only potentially hot, it is not being moved; when it has now been heated, the motion of heating is finished; but when it possesses “ some heat, through imperfectly, then it is being moved—for whatever is being heated gradually acquires heat step by step. Therefore this imperfect act of heat existing in a heatable object is motion—not, indeed, by reason of what the heatable object has already become, but inasmuch as, being already in act, it has an order to a further act. For should this order to a further act be taken away, the act already present, however, imperfect, would be the term of motion and not motion itself—as happens when something becomes half-heated. This order to a further act belongs to the thing that is in potency to it.

Similarly, if the imperfect act were considered solely as ordered to a further act, under its aspect of potency, it would not have the nature of motion but of a principle of motion—for heating can begin from either a cold or a lukewarm object.
The imperfect act, therefore, has the character of motion both insofar as is compared, as potency, to a further act, and insofar as it is compared, as act, to something more imperfect.

Hence, motion is neither the potency of a thing existing in potency, nor the act of a thing in act, but it is the act of a thing in potency; where the word “act” designates its relation to a prior potency, and the words “of a thing in potency” designates its relation to a further act.

Whence the Philosopher most aptly defines motion as the *entelechy, i.e., the act, of a thing existing in potency insofar as it is in potency.

My question is how can what I have underlined in the St. Thomas quote be reconciled with one another? Also, how can motion be conceived atemporally? E.g., what does God, being atemporal, “see” when something in undergoing motion, e.g., water being heated from cold to hot? Are things in motion a superposition of potency and act when viewed atemporally? I seem to think motion is a subjective thing experienced by those bound to time, but why would an observer being temporally bound or not affect whether something objective is in potency or act or, as I don’t quite see as possible, somewhere in between potency and act? From God’s perspective is Parmenides right to think there is no motion? Thanks for the help

 

[Ghosty]

I’ll do my best to answer your questions.

My question is how can what I have underlined in the St. Thomas quote be reconciled with one another?

All that is being said is that act and potency are divided in that something must either be in potency to something, or in act. This doesn’t mean that a thing can’t be in potency in a certain way, and in act in another. When I am moving to the next room I am in potency towards being in that room, but I am actually here right now, and when I am in that room and stopped I will be perfectly “in act” of being in that room. Aquinas explains this a bit after the second underlined portion when he says:

Therefore this imperfect act of heat existing in a heatable object is motion—not, indeed, by reason of what the heatable object has already become, but inasmuch as, being already in act, it has an order to a further act.

…

Hence, motion is neither the potency of a thing existing in potency, nor the act of a thing in act, but it is the act of a thing in potency; where the word “act” designates its relation to a prior potency, and the words “of a thing in potency” designates its relation to a further act.

So while the object is indeed in act, it is also in potency and is taking “step by step” acts towards a final act. This is why Aristotle adds “in so far as it exists potentially”, because the final act still exists potentially in the object, and once the final act is actual and not potential, motion has stopped.

Are things in motion a superposition of potency and act when viewed atemporally? I seem to think motion is a subjective thing experienced by those bound to time, but why would an observer being temporally bound or not affect whether something objective is in potency or act or, as I don’t quite see as possible, somewhere in between potency and act? From God’s perspective is Parmenides right to think there is no motion? Thanks for the help

From God’s perspective there is no motion, not because the things themselves don’t move, but because God’s gaze covers all points of motion at once. So it’s not so much that there is no motion per se, but rather that God’s vision transcends motion, because God transcends time itself (which, according to Aristotle, is simply the measure of motion).

So when God sees a pot of water, for example, God sees all the states of temperature at once. This doesn’t mean that God doesn’t see motion in the strict sense, however, because God sees that one step leads to the next, even though those steps are not seperated by time in God’s view. This is something beyond our comprehension, but an analogy might help a little bit. If you look at a flow-chart of events, each event occurs in sequence, according to the flow of the chart from beginning to end, but in another sense all events occur at the same time, being as they all exist at once in the chart itself. When looking at the chart you are both looking at a sequence of “time”, and a single event (the chart). This is analogous to God seeing each creature and action acting/occuring step by step, and also seeing all time as a single eternal moment. This also helps to illustrate how a timeless being can interact with time, as someone looking at the flow chart can write in information between events, and such notes exist “at once” with the rest of the chart, but also in sequence within the chart.

Hope that helps!

Peace and God bless!

 

[greylorn]

Aristotle defines motion in Phys. III, 1 as “The fulfilment of what exists potentially, in so far as it exists potentially.” Expanding on this in In Phys. III, 2, St. Thomas says:My question is how can what I have underlined in the St. Thomas quote be reconciled with one another? Also, how can motion be conceived atemporally? E.g., what does God, being atemporal, “see” when something in undergoing motion, e.g., water being heated from cold to hot? Are things in motion a superposition of potency and act when viewed atemporally? I seem to think motion is a subjective thing experienced by those bound to time, but why would an observer being temporally bound or not affect whether something objective is in potency or act or, as I don’t quite see as possible, somewhere in between potency and act? From God’s perspective is Parmenides right to think there is no motion? Thanks for the help

When my children asked me why the sky was blue, I did not invent some obfuscating answer. I said that when you grow up, if you choose to study physics, you will learn the science of optics. It will explain these things, as well as questions you have yet to ask, such as the origin of rainbows, or how my camera takes your cute photos.

No potentials or actualities, and I did not even use the words “diffraction,” or “atmospheric absorption,” which would have been meaningless obfuscations (to children, or to Discovery Channel viewers), much like the obfuscations of Aristotle and Aquinas, who could not generate legitimate answers to any questions relating to physics, and so made up some garbage.

As a result of telling my offspring the truth, they all graduated from some college or university.

Why am I posting you? The subject of motion is interesting, but I was sorely disappointed by the direction of this thread. If you have a genuine interest in the nature of motion (which is indeed still a mystery), why look to philosophers or religionists for elucidation? Study physics. The science was founded by Galileo, who studied motion. His papers are all in the public domain, and require only grade school mathematics to understand. Then, graduate to Newton, who will teach you calculus while explaining motion. In time, Max Planck will take the puzzle of motion one step further.

If your curiosity is genuine, you can satisfy it. But there is no easy, simple minded way to do so.

 

[Ghosty]

Why am I posting you? The subject of motion is interesting, but I was sorely disappointed by the direction of this thread. If you have a genuine interest in the nature of motion (which is indeed still a mystery), why look to philosophers or religionists for elucidation?

If you understood what is actually being discussed you would understand that a ) this definition of motion goes WAY beyond physics, and b ) this definition is still applicable to modern physics. The point of the philosophical question is to find a definition of motion that applies to all kinds of movement (including non-physical, like movements of the will), not a calculation of physical forces which is what the people you mentioned do.

If you don’t intend to understand the philosophical definition of motion, why even post in the Philosophy forum?

Peace and God bless!

 

[Ace_of_Spades]

When my children asked me why the sky was blue, I did not invent some obfuscating answer. I said that when you grow up, if you choose to study physics, you will learn the science of optics. It will explain these things, as well as questions you have yet to ask, such as the origin of rainbows, or how my camera takes your cute photos.

No potentials or actualities, and I did not even use the words “diffraction,” or “atmospheric absorption,” which would have been meaningless obfuscations (to children, or to Discovery Channel viewers), much like the obfuscations of Aristotle and Aquinas, who could not generate legitimate answers to any questions relating to physics, and so made up some garbage.

As a result of telling my offspring the truth, they all graduated from some college or university.

Why am I posting you? The subject of motion is interesting, but I was sorely disappointed by the direction of this thread. If you have a genuine interest in the nature of motion (which is indeed still a mystery), why look to philosophers or religionists for elucidation? Study physics. The science was founded by Galileo, who studied motion. His papers are all in the public domain, and require only grade school mathematics to understand. Then, graduate to Newton, who will teach you calculus while explaining motion. In time, Max Planck will take the puzzle of motion one step further.

If your curiosity is genuine, you can satisfy it. But there is no easy, simple minded way to do so.

I was enjoying this thread please don’t pollute it with hysterical ravings. Thanks.

 

[Geremia]

All that is being said is that act and potency are divided in that something must either be in potency to something, or in act. This doesn’t mean that a thing can’t be in potency in a certain way, and in act in another.

I think this is exactly with what I was struggling. Thank you!

 

[Geremia]

If you understood what is actually being discussed you would understand that a ) this definition of motion goes WAY beyond physics, and b ) this definition is still applicable to modern physics.

What makes you think I am just talking about this definition restricted to modern physics? Was it because I used the water heating example?

The point of the philosophical question is to find a definition of motion that applies to all kinds of movement (including non-physical, like movements of the will), not a calculation of physical forces which is what the people you mentioned do.

What people did I mention? Parmenides?

If you don’t intend to understand the philosophical definition of motion, why even post in the Philosophy forum?

I am intending to understand it philosophically. What makes you think otherwise?

 

[greylorn]

I was enjoying this thread please don’t pollute it with hysterical ravings. Thanks.

I sure won’t do that anymore, now that I realize that before posting to this thread I need to register with the local thought police. Is there a Chief of Police I should have queried first, or are you the LieuteNit in Charge? Are there other threads you are policing for which I should request your pre-post approval? Do let me know.

And I apologize for waking you up, if you can tell the difference.

 

[Ace_of_Spades]

I sure won’t do that anymore, now that I realize that before posting to this thread I need to register with the local thought police. Is there a Chief of Police I should have queried first, or are you the LieuteNit in Charge? Are there other threads you are policing for which I should request your pre-post approval? Do let me know.

And I apologize for waking you up, if you can tell the difference.

My suggestion is you grow up and don’t act like a prat. Thanks