This thread has all three - critiques, dismissals and ridicule, as well as a spirited defence of Aristotle's position put up by some of the worthy resident Aristotelians. If you don't mind having to sift out the critiques from the Ds and Rs, you may find it helpful.

My impression was that the key differences of opinion were over what constitutes a 'definition', and what constitutes a 'proof'.

My impression that the key differences of opinion were over what constitutes a 'definition', and what constitutes a 'proof'. — andrewk

No wonder philosophy discussions on forums never get anywhere. It always turns into a semantic dispute over terms people normally have no trouble understanding.

I am more optimistic. I have learned a great deal from discussions on this forum and its predecessor. Even in that discussion, while no agreement was reached, I emerged from it feeling I had a better understanding of the Aristotelian worldview and why some people are very dedicated to it.

Non do I find the arising of such disputes surprising. You and I would both agree what 'big' means when we are talking about a cat, as it is in the context of things like cats that we learned to use the word 'big'. Why should we be surprised that we have different interpretations of 'big' when it is applied to things like universes or multiverses, that are completely removed from the scope in which we learned those words and in which they are applicable. I would be astonished if such disputes did not arise.

Thanks andrewk. I posted my issue there, but will do so here as well.

I have several problems with Feser's argument.
1. His Principle of (Aristotelian) Causality: Every change is a change from potentiality to actuality brought about by something with the actuality in question.
2. His Principle of (Hierarchical) Sustaining Causality
3. His claim that the existence of anything is the result of the actualizing of the potential to exist by something already actualized as existent.
4. His claim that anything that already existing cannot continue to exist with out something sustaining that existence, continually actualizing the (so-called) potential for existing.
5. His claim that while there may be an infinite chain of (temporally extended) initiating causes, there can not be an infinite chain of simultaneous sustaining causes.

What I would like to know is whether there are any good arguments against these theses, especially #1 and #3. #3 seems to treat existence as a property that something may have as either potentially or actually, similar to the potential for hotness. And that just as something that is actually hot "activates" the potential for hotness in another object, so to something that exists activates the potential for existence in another.

The problem I have is with Feser's (Aristotle's and Aquinas's) view of causality. I'd like to think that it is not just a disagreement about the meaning of the term 'cause', but rather about what account we can give of the causal relation, viz., what makes the proposition ^A causes B^ to be true?

I don't find their notion of causality to be coherent. The notion of a simultaneous cause (item 5) goes against the common understanding of what a cause is, as well as all coherent philosophical definitions I have seen. I have seen an attempted defence of the notion of 'simultaneous cause' using terms like 'logically prior, rather than temporally prior'. But Logically Prior is usually left undefined and when one tries to nail it down it evaporates.

There are attempted examples out there of 'simultaneous causes' (eg the dent in a pillow from a rock that is sitting on it) but they generally rely on failing to understand physics.

I don't have a problem with the notion of a sustaining cause, whose activity would be simultaneous, What I question is the notion of a hierarchy of such causes. In addition, both his notion of initiating cue and sustaining cause relies on this Potentiality/Actuality model, which is what I am questioning. The example that comes to mind is a microwave oven. Microwaves cause something to go from cold to hot. On his model of causality, this is because the microwaves are actually hot!

The notion of a simultaneous cause (item 5) goes against the common understanding of what a cause is, as well as all coherent philosophical definitions I have seen. — andrewk

I do not think that "simultaneous cause" is Aristotelian. In my understanding of Aristotle's four ways that "cause" is used, cause is always temporally prior. Some people interpret final cause (and this is probably a more common interpretation) as posterior. This is because they apprehend the existence of the material object caused, as the cause, and do not acknowledge the immaterial form which is prior to the object's material existence, as the actual cause.

I believe it is this ambiguity in meaning of final cause, which leads to the idea of a simultaneous cause. When the final cause, as the cause of existence of an object, cannot be properly located, as prior to the material existence of the object, and the need to assume it only arises after the material existence of the object, then it is positioned as simultaneous with the object (as a type of compromise).

Microwaves cause something to go from cold to hot. On his model of causality, this is because the microwaves are actually hot! — Mitchell

I believe I explained this in the other thread where you posted. To go from cold to hot, a potential to an actuality requires an actuality, but the actuality is not the same actuality as that achieved. So the microwaves are an actuality, but they are not necessarily actually hot.

We have the potential for something, say the potential for the food to be hot. The food is not actually hot, and there is no necessity that the food will become hot. That is the key to understanding potential, the lack of necessity, contingency. So with potential, that particular potential may or may not be fulfilled. And, there are countless other possibilities, potentials which may be fulfilled beside that one. The food might become warm, it might get burnt, it might not get heated at all. This is contingency.

What happens to the food, which potential gets actualized, depends on the efficient causes applied. This is why an actuality, an activity, is required to actualize any potential. So the argument is that if anything actually exists, then prior to that existence was the potential for that thing which exists. However, a further actuality (activity if you like) is required, to bring that actual thing from the potential for that thing to the actual existence of that thing.

I'm sorry, but I must be dense. I see two issues here. First issue is that any change requires an existing (actual) cause, for something cannot come from nothing. Thus the cause of the food going from cold to hot is something actual, the microwaves. OK. But, second, according to Feser, not only must the cause of the change from cold to hot exist prior to the change, and bring about the change, but it also must have in actuality hotness: what causes hotness must itself be hot. Based on your remarks, either I have misunderstood Feser or Feser is confused about Aristotelian causality.

OK. But, second, according to Feser, not only must the cause of the change from cold to hot exist prior to the change, and bring about the change, but it also must have in actuality hotness: what causes hotness must itself be hot. — Mitchell

I see in #3, that the cause must be "actualized as existent":

3. His claim that the existence of anything is the result of the actualizing of the potential to exist by something already actualized as existent. — Mitchell

How do you infer that the cause must be a particular type of actuality "itself be hot"?

His example of the coffee getting cold because of the cold air from the air conditioner. Also, his interpretation of "Formal Causality" seems to suggest a "transfer" of Form, in this case the form coldness. If all he is saying is that the cause of hotness or coldness must be some existing characteristic of the cause, but not specifically actual hotness or coldness, this account of qualitative change seems to be so vague as to be uninformative.

I would be astonished if such disputes did not arise. — andrewk

But when I go and read on SEP, or a layman's philosophy book, it doesn't get bogged down with semantics. Things are defined as needed to setup the argument or examine the different positions, and that's that.

What really brings the issue to mind was a discussion on here a while back concerning whether color irrealism was a threat to direct realism. That went about 31 pages until the discussion was completely derailed by arguments over what "direct" and "realism" meant.

His example of the coffee getting cold because of the cold air from the air conditioner. Also, his interpretation of "Formal Causality" seems to suggest a "transfer" of Form, in this case the form coldness. If all he is saying is that the cause of hotness or coldness must be some existing characteristic of the cause, but not specifically actual hotness or coldness, this account of qualitative change seems to be so vague as to be uninformative. — Mitchell

I'm not familiar with the examples, I'm only going on what #3 says, along with my understanding of the Aristotelian explanation of causation. It may seem uninformative, but it becomes important in the context of the cosmological argument.

If we look at all material things as temporal, meaning that they come into existence, and contingent, meaning that the potential for them precedes the actual existence of them, then to avoid an infinite regress of material things we must assume a first material thing. By the description, or definition of "material thing", it is necessary that the potential for that thing existed prior to the thing itself. Now we need an actuality to account for that potential being actualized, so we must conclude that there is an actuality which is other than a material thing.

Isn't that because books and SEP articles are monologues, and disputes only arise if there are two or more people communicating?

I do not think that "simultaneous cause" is Aristotelian. — Metaphysician Undercover

Now that you mention it, that sounds right. , do you recall where that statement about 'simultaneous causes' came from?

How do you infer that the cause must be a particular type of actuality "itself be hot"? — Metaphysician Undercover

His example of the coffee getting cold because of the cold air from the air conditioner. Also, his interpretation of "Formal Causality" seems to suggest a "transfer" of Form, in this case the form coldness. If all he is saying is that the cause of hotness or coldness must be some existing characteristic of the cause, but not specifically actual hotness or coldness, this account of qualitative change seems to be so vague as to be uninformative. — Mitchell

Science recognizes two different modes of heating; conduction (or convection) and radiation. In the former heat is conducted from something hotter (air, water, a metal container and so on) to something less hot. On the other hand, an example of radiation is the sunlight heating a brick wall or your body. The light itself is not hot, just as the microwaves that heat the coffee are not themselves hot. In both cases the theory is that the radiation agitates the molecules to move faster and this faster movement manifests as heat.

Pages 60-63 is the discussion of "simultaneous causes"

Yes! And I think that heat by radiation provides an example where the Aristotelian account of change fails. But then, some think I misunderstand that account of causation. Again, my understanding of that account of causation is that object A can cause object B to go from being potentially X to being actually X only if object A is itself actually X.

I can't find the text on the internet. But I saw the page on Amazon and was interested to see that the first user review says:

'The purpose of the book is to prove the existence of God, and Aristotle's arguments are just a tool to that end, and a tool that Feser has no qualms about changing and adapting to fit his needs.'

If that's correct then I imagine that in the proof that Feser describes as Aristotelian, the 'simultaneous cause' bits were added by him, not present in Aristotle's (or Aquinas's) original version. He would have done better to have presented the Aristotle or Aquinas version.

On the other hand, an example of radiation is the sunlight heating a brick wall or your body. The light itself is not hot, just as the microwaves that heat the coffee are not themselves hot. In both cases the theory is that the radiation agitates the molecules to move faster and this faster movement manifests as heat. — Janus

I had a thread once where I asked about the nature of heat radiation. There is a curious thing about the radiation of heat. In the way it is described, it appears like in order for an object to radiate heat, there must be an object to receive that radiation, just like in conduction, there must be a colder object to receive heat from the warmer. But many argued that an object may radiate heat into nothing, vacuum space, or something like that.

I think the issue is in the definition of "heat". Heat is a measurement of energy transferred from one object to another. Therefore radiation, as the medium between one object and another, is not actually heat until it is received by the other object. So for heat to be radiated requires that it be received by another object. And although we say that heat is what is transferred from one object to the other, the radiation itself, which is what exists between the objects, is not actually heat, it is the means by which heat is transferred.

Again, my understanding of that account of causation is that object A can cause object B to go from being potentially X to being actually X only if object A is itself actually X. — Mitchell

I think that this is very clearly a misunderstanding. According to Aristotle's law of identity, an object is the same as itself. No two objects may have the same identity. So if an object becomes actually X, it is impossible that the object which caused it to be actually X, could itself be actually X, as that would defy the law of identity. Two distinct objects would be actually X.

He would have done better to have presented the Aristotle or Aquinas version. — andrewk

I think that's probably right. Feser's argument seems to be long and convoluted. Aquinas' is less so, but still quite complicated. Aristotle's cosmological argument is the most simple, and easy to understand. As I explained in a post above, it leads to the conclusion of an actuality which is prior to temporal, contingent things, so long as we deny an infinite regress of things.

The problem is that "time" in its general conception, is defined by the activities of those contingent things. This puts that actuality, outside of time, therefore eternal. So Aristotle proposed eternal circular motion, a circle so perfect that there could be no beginning or end. This is similar in conception to the modern Hartle-Hawking no-boundaries proposal. The theists take Aristotle's cosmological argument and adapt it for their purposes. But this increases the complexity by adding principles to adapt this pre-temporal actuality to God.