My bolds. I had read previously that 'mother' and 'matter' were etymologically related but never knew how. — Wayfarer

Plato described matter in Timaeus in sexist terms, coming from ancient myths. It is a passive principle which receives the form, like being impregnated. Notice also the duality in "conception". Plato plays with that duality in Theatetus, when Socrates refers to himself as a midwife.

The issue of the intellect receiving the form of the object, in conception, becomes a difficult question for Aquinas. In order to receive the form of an object, the intellect must have a passive aspect. The passive aspect is a potential, like matter, but Aquinas wants to maintain the immaterial essence of the intellect, and I think he refuses to refer to this passive aspect as material in nature. The way I understand this issue is that the intellect is essentially immaterial, but it has material accidentals. The accidentals are what individuate us as distinct, separate, and unique human beings.

Another point: that Aristotelian dualism comprised 'matter and form', not the Cartesian 'matter and mind'. — Wayfarer

What Aristotle does, which is not as evident in Plato (except perhaps Timaeus), is extend the duality of reality into all things, all objects, not just human beings. Notice that Descartes brings us back to the primitive form of dualism, similar to the dualism expressed by the myths described by Plato. Plato demonstrated how difficult it is to make sense of this dualism. From this position, where dualism is extremely difficult to make sense of, we have the choice of two distinct directions. We can dismiss dualism as simply incoherent (as is the modern trend), or we can follow a system like Aristotle's, which extends dualism into all aspects of reality. I find that the cosmological argument is very important because it demonstrates very forcefully, and decisively, that the only rational way to proceed is to extend dualism.

To those others discussing "prime matter", the cosmological argument denies the possibility that the concept of prime matter could refer to anything real.

I don’t understand the above though. Since matter isn’t composite, doesn’t that mean the same matter underlies every object? In which case the only way to distinguish between objects is by their forms; but why then do individual objects remain the same objects as their forms change? — AJJ

This is a good question, and I think that the best way to proceed is to understand "matter" as an assumption. Aristotle assumed "matter" as the principle of continuity of existence. Ultimately, it accounts for the fact that the world cannot be randomly different from one moment to the next. Newton characterized this as inertia. I understand matter as the continuity of time itself. Modern physics now uses "energy" (conservation of energy), to refer to that which remains, or persists, through change, this allows the principle of continuity to cross between one object and another, such that the continuity of an object is no longer assumed in physics, as it is in Aristotelian physics.

The issue of the intellect receiving the form of the object, in conception, becomes a difficult question for Aquinas. — Metaphysician Undercover

The quotes in this post are all exactly about that, and, I must confess, make perfect sense to me.

I understand matter as the continuity of time itself. — Metaphysician Undercover

Yeah, time is change and matter allows there to be change.

Aristotle assumed "matter" as the principle of continuity of existence. Ultimately, it accounts for the fact that the world cannot be randomly different from one moment to the next. — Metaphysician Undercover

I guess I don’t see why it does account for that; if matter is pure potentiality then it can be anything from one moment to the next. So this is where I like Platonism: the notion that there is an organising principle (Soul), which fashions the world after the Forms. That way it seems an object remains the same object throughout changes so long as it’s participating in the same Forms.

Therefore, to discuss what Aristotle meant by "matter" is a mug's game, because he did not mean any thing by it!
— tim wood

But in the second paragraph you shared he explicitly says what he means by it; Augustine and Aquinas appear to have gotten it right. — AJJ

Stanford.edu: "By “matter” I mean that which in itself is not called a substance nor a quantity nor anything else by which being is categorized. For it is something of which each of these things is predicated, whose being is different from each of its predicates (for the others are predicated of substance, and substance is predicated of matter). Therefore this last is in itself neither substance nor quantity nor anything else. Nor is it the denials of any of these; for even denials belong to things accidentally. (1029a20–26) — tim wood

Here's the second paragraph. Now read it again and tell me what Aristotle (according to Stanford.edu) says matter is. "Matter is...not...nor...nor...neither...nor...nor... Nor even not.

I must have missed it. What is it he says explicitly matter is?

For it is something of which each of these things [that it is not] is predicated, whose being is different from each of its predicates (for the others are predicated of substance, and substance is predicated of matter).

In other words: pure potentiality.

In other words: pure potentiality. — AJJ

Whose words? And what is the being of "pure potentiality" if you trouble to make sure that it has no being?

Near as I can tell, for Aristotle, "matter" is a place holder for he-knows-that-he-knows-not-what-but-that-he-supposes-is. Nothing wrong with that, nor do I imagine that he was ever confused about the negative nature of his understanding. He specified what it wasn't, and was, if anyone ever was, smart to know that what it wasn't wasn't in any way what it was. A level of intellection for the rest of us to aspire to.

And he was wrong with respect to any modern sense or usage or understanding of matter. It belongs, then, to the history of ideas. Which Wayfarer reminds us is a valuable possession:

I think it is quite useful to trace how Aristotelian (and other classical) terms and ideas, like 'hyle', 'ousia', 'esse', and so on, have been translated and interpreted over time. — Wayfarer

Except that for "useful" I'd say interesting. Not to deny use, but rather to acknowledge that its use was particular to certain ideas and certain times, the way a touch-hole is particular to muzzle-loaded cannon, but itself of no use in modern artillery, the mention of which in modern context must be "quaint" - meaning odd - at best.

In other words: pure potentiality.
— AJJ

Whose words? — tim wood

From the first paragraph you quoted earlier:

The traditional interpretation of Aristotle, which goes back as far as Augustine (De Genesi contra Manichaeos i 5–7) and Simplicius (On Aristotle’s Physics i 7), and is accepted by Aquinas (De Principiis Naturae §13), holds that Aristotle believes in something called “prime matter”, which is the matter of the elements, where each element is, then, a compound of this matter and a form. This prime matter is usually described as pure potentiality

———

And what is the being of "pure potentiality" if you trouble to make sure that it has no being? — tim wood

It has no being; it’s rather the potential to be.

Or I guess that it has no actuality is the better way to put it.

it’s rather the potential to be. — AJJ

Well, no. This sounds good, but in the next paragraph

(Stanford.edu) Nor is it the denials of any of these; for even denials belong to things accidentally. — tim wood

And we're in Heideggerian territory where the nothing "noths." And that way madness lies, and nonsense, unless people take care - sometimes a lot of care. Reification is a real disease that modern knowledge is only a partial inoculation against- except in this case even reification doesn't work, because you can't reify an isn't.

My purpose is to (attempt) to apply rigour to the idea of Aristotle's matter - if I can, if I have. Aristotle had a theory with a hole in it. He manifestly knew that as well or better than anyone else. And apparently he was able to identify some of the boundaries beyond which lay his terra incognita, except that it wasn't merely unknown, but expressly unknowable.

For anyone then to claim to know it, then, is simply the fallacy of, "Because I do not know, I know." The Christians actually did not commit that fallacy. They simply reworked the idea to their own ends. But they left Aristotle's name on their ideas. Thus the history of ideas hauls behind a tail of the confusion of ideas.

If you mount a prefabricated fiberglass Porsche body over a Corvair frame, engine, and running gear, what do you have? Maybe someone's fantasy project of a Porsche, but nothing you'd want to put on the road.

Or I guess that it has no actuality is the better way to put it. — AJJ

But here I think you've got it, and said it shortest and best!

it’s rather the potential to be.
— AJJ
Well, no. This sounds good, but in the next paragraph
(Stanford.edu) Nor is it the denials of any of these; for even denials belong to things accidentally.
— tim wood — tim wood

I think that simply means you can’t say matter doesn’t have whatever properties for the same reason you can’t say it does: it’s pure potentiality - it can have or not have whatever properties you like, just not of itself.

Or I guess that it has no actuality is the better way to put it.
— AJJ
But here I think you've got it, and said it shortest and best! — tim wood

Well there you go; that’s just another way of saying it’s pure potentiality.

*grumble* Ok. That is to say that what it is, is pure 200-proof isn'tness. I yield the playpen.

Sure :up:

You are right to point to the problems with what Aristotle says about matter. But I think he was smart enough to recognize that it is problematic. In fact, I think that is exactly where he leads the thoughtful reader. He, like Plato and Socrates, is a zetetic skeptic (not to be confused with modern versions of skepticism). We simply do not know and so cannot say what 'is' at the most fundamental level.

Of course, this does not stop people from making such claims. So, it is better he tell his own stories, reasonable stories, beneficial stories.

The quotes in this post are all exactly about that, and, I must confess, make perfect sense to me. — Wayfarer

I mostly agree with what's in those quotes, except this:

The individuality of the object cannot be due to any of those abstractions, which are universals, and so must be due to something else. To Aristotle that was the "matter" of the object. "Matter" confers individuality, "form" universality. — Kelly Ross

Aristotle actually distinguishes two primary senses of "form", the form which we grasp, the universal, or the essence of the thing, and the form of the particular. The form of the particular includes all the accidentals, which are left out from the essence. We do not grasp the entirety of the thing's form. So it is not matter which confers individuality, it is form, but it is the property of a material thing, to be an individual. We have in Aristotle a distinction between form as essence, abstraction, or universal, and the form of the particular, material thing.

It is in understanding that each individual object has a distinct, and unique form, that you may come to realize that the form of a particular object is necessarily prior to the material existence of that particular object. This is one way that we come to see that form is prior to material existence. Material objects come into being. When a thing comes into being, it must be the thing which it is, and not something else. It is impossible that a thing is other than itself, by the law of identity. Further, a thing is an ordered unity, it is not random. By these two premises, it is necessary to conclude that what the thing is (its form) precedes its material existence.

I guess I don’t see why it does account for that; if matter is pure potentiality then it can be anything from one moment to the next. — AJJ

Sure, but for Aristotle prime matter, or pure potentiality, is incoherent, unintelligible, a logical impossibility by the cosmological argument. Simply put, a potentiality requires an actuality to be actualized. If there ever was a time when there was pure potential, there would be no actuality at that time, and therefore the potential could not ever be actualized, so there would always be pure potential with no actuality. However, we observe that there is actuality, so it is impossible that there ever was pure potentiality.

So this is where I like Platonism: the notion that there is an organising principle (Soul), which fashions the world after the Forms. That way it seems an object remains the same object throughout changes so long as it’s participating in the same Forms. — AJJ

The problem with the theory of participation, which Plato uncovered, and becomes evident from The Republic on, into his later work, is that the thing which is participated in is passive, as the thing participating is active. What Plato discovered, and this constitutes his proposal of "the good", is that in order for the Forms to have any real participation in the real world, they must be active, actual. He found this principle of action in "the good". We act for what we perceive as the good, and the Ideas, or Forms are directed towards the good, such that they receive actuality in this way, from the good.

This is why the philosopher in the cave turns things around, realizing that what the people in the cave see as reality, the material objects, are really reflections, representations of the Forms, which are actively causing the existence of material objects, which the cave people take as the totality of reality. So a material object does not participate in the Forms, the Forms actively cause the existence of the thing by informing the matter. This makes matter the passive aspect of reality, while Forms may participate in passivity by remaining the same, and having the potential to change.

What is it he says explicitly matter is? — tim wood

Is this a trick question? The whatness of a thing is the thing's form. Matter is distinct from form. So it makes not sense to ask "what is matter", because asking "what", is asking for a form. If someone tried to tell you what matter is, they'd be handing you a form, saying "this is matter".

However, we observe that there is actuality, so it is impossible that there ever was pure potentiality. — Metaphysician Undercover

I assume that’s where the unmoved mover figures. Besides, whether formless matter ever was doesn’t change the fact that pure potentiality is the what prime matter is conceptualised as; and being so means it must be whatever is actualising it that prevents the world from being drastically different from one moment to the next, which is what I was quibbling about.

The problem with the theory of participation, which Plato uncovered, and becomes evident from The Republic on, into his later work, is that the thing which is participated in is passive, as the thing participating is active. — Metaphysician Undercover

That’s fine. From reading a bit about Plotinus I take participation to mean being fashioned by Soul in imitation of whatever Forms.

Aristotle actually distinguishes two primary senses of "form", the form which we grasp, the universal, or the essence of the thing, and the form of the particular. — Metaphysician Undercover

Those quotes I referred to make a very clear point: the material senses (eyes, ears) perceive the particular being, the intellect perceives the form. The material thing must always, of necessity, be apart from us - in modern terms, an object to us, something outside of us. But 'the form' is known directly by nous, as the form is basically an idea, not a thing. That is the 'rational intellect' in operation.

(2) I think it's a common mistake to equate 'form' with 'shape'. The 'form' is not 'the shape' (or even 'what something appears to be'). The form is 'the type of thing it is'. We recognise a [chair/apple/tree/triangle] because we know the meaning of the concepts, what it is that gives the object its identity. It's partially shape or appearance, but it's something much more than that.

What do you think?

Aristotle actually distinguishes two primary senses of "form", the form which we grasp, the universal, or the essence of the thing, and the form of the particular. The form of the particular includes all the accidentals, which are left out from the essence. We do not grasp the entirety of the thing's form. So it is not matter which confers individuality, it is form, but it is the property of a material thing, to be an individual. — Metaphysician Undercover

I think you're mistaken, but at least here, we can be very clear about the confusion, which should be instructive.

My thought is that there is no 'form of the particular' because 'forms' by definition are *not* particular but universal. Read this passage again: 'The proper knowledge of the senses is of accidents, through forms that are individualized; the proper knowledge of intellect is of essences, through forms that are universalized.' And 'a particular being' is precisely a combination of accidents and universals, of (individualised) matter and (universal) form. Hence, hylomorphic, matter-form, dualism.

Socrates is of the [form or type] Man, but happens to have flat nose, etc, which pertain to him as an individual. It is 'the accidents' which confer individuality. But insofar as Socrates is a man, he is a form, or a universal.

Besides, whether formless matter ever was doesn’t change the fact that pure potentiality is the what prime matter is conceptualised as; and being so means it must be whatever is actualising it that prevents the world from being drastically different from one moment to the next, which is what I was quibbling about. — AJJ

The point though, is that it is impossible to conceptualize something which is logically impossible. You can say it "prime matter", but you cannot conceptualize it.

That’s fine. From reading a bit about Plotinus I take participation to mean being fashioned by Soul in imitation of whatever Forms. — AJJ

The Neo-Platonists, like Plotinus use a different conception of participation than the one Plato described derived from the Pythagoreans. This follows the difficulties with the original theory of participation revealed by Plato and Aristotle. I believe Plotinus uses a system of "emanation", and some other Neo-Platonists refer to a "procession". But this is a participation of Forms, strictly, and I don't think material existence is even necessitated in Plotinus' system.

Those quotes I referred to make a very clear point: the material senses (eyes, ears) perceive the particular being, the intellect perceives the form. The material thing must always, of necessity, be apart from us - in modern terms, an object to us, something outside of us. But 'the form' is known directly by nous, as the form is basically an idea, not a thing. That is the 'rational intellect' in operation. — Wayfarer

The senses, and the intellect are both powers of the soul. They both perceive a form. "Form" refers to what a thing is. The senses perceive the form of the particular (though this perception is deficient), while the intellect may apprehend the essence, which is the universal form. So for instance, through my senses I perceive the form of the particular object in front of me, my laptop, but this perception of the object is deficient, because I am only actually perceiving certain aspects of the form, its shape, colour, etc.. At the same time, my intellect apprehends the form of the thing in the sense of "laptop", recognizing the essence of the thing as a laptop.

The form is 'the type of thing it is'. — Wayfarer

Aristotle is very clear on this point, form refers to whatness, (I think it's called quiddity) what a thing a thing is. He starts with "form" as the type of thing, but proceeds to examine "form" in the sense of the individuality of a thing. This is made necessary by his law of identity which he proposed as a law against sophism. The sophist could claim that two things which are the same type, are actually the same thing. So the law of identity designates that two distinct things which appear to be the same (are the same type) cannot actually be the same thing. Since they are in fact distinct, there must be some formal aspects which distinguish one from the other. Remember, the intellect only apprehends form, so the distinction between two things must be formal if the intellect is to be able to grasp it.

Individual particular objects have a form proper to themselves. You'll see that this is one of the main topics Aristotle investigates in his Metaphysics, where he investigates being qua being. He dismisses the commonly quoted "why is there something rather than nothing", and poses instead, the question of "why is there what there is instead of something else". So this question becomes why is a particular object what it is, and not something else. This is because it is given a particular form. He's very specific on this point, a particular thing has a form unique to itself.

My thought is that there is no 'form of the particular' because 'forms' by definition are *not* particular but universal. Read this passage again: 'The proper knowledge of the senses is of accidents, through forms that are individualized; the proper knowledge of intellect is of essences, through forms that are universalized.' And 'a particular being' is precisely a combination of accidents and universals, of (individualised) matter and (universal) form. Hence, hylomorphic, matter-form, dualism. — Wayfarer

I think if you read more you'll find it very clear that Aristotle proposed a form of the particular. "Accidents" are formal, part of a thing's form, they are just not part of a things essence.

The senses, and the intellect are both powers of the soul. — Metaphysician Undercover

Nope. One is material, the other intellectual. Otherwise, why is it ‘dualism’? And why doesn’t the soul simply die with the body?

The point though, is that it is impossible to conceptualize something which is logically impossible. You can say it "prime matter", but you cannot conceptualize it. — Metaphysician Undercover

I guess I just don’t see why conceiving of prime matter as pure potentiality is problematic. The concept seems fairly straightforward to me; I mean whatever exists materially must have the potential to do so, right? So that potential is prime matter.

I believe Plotinus uses a system of "emanation", and some other Neo-Platonists refer to a "procession". But this is a participation of Forms, strictly, and I don't think material existence is even necessitated in Plotinus' system. — Metaphysician Undercover

Plotinus characterises bodies as being ‘in’ Soul, in a relationship of dependence. So I take participation to be that: a relationship of dependence. Plotinus has it that the One, being beyond the constraint of ignorance, creates freely and not of some necessity beyond its control; an important distinction I guess, although it seems to me it amounts to the same thing - since to not create would presumably then be an error made in ignorance, and so not free, and so impossible.

What is it he says explicitly matter is?
— tim wood

Is this a trick question? The whatness of a thing is the thing's form. Matter is distinct from form. So it makes not sense to ask "what is matter", because asking "what", is asking for a form. If someone tried to tell you what matter is, they'd be handing you a form, saying "this is matter". — Metaphysician Undercover

Egads! It's worse than I thought! It's not just that matter in Aristotle's thinking is problematic, but that you cannot even ask about it!

And btw, the "what" referred to what Aristotle says about matter. It's right there above: "What is it he says...? So the question stands: what does he say about it? Please before opinionating, please consult citations above in this thread and https://plato.stanford.edu/entries/form-matter/ . What Aristotle said is a matter of fact, not opinion.

Now I make a claim about Aristotle. He was operating with wrong presuppositions, and his efforts at science were therefore and thereby infected with error. As a matter of the history of ideas, his conclusions are interesting. But they're not modern science. As noted above, his "matter" is that which not only isn't, but isn't even an isn't, and cannot even be asked about. it's a plug-placeholder for a problem that Aristotle encountered in giving an account that he did not solve and that he knew perfectly well that he did not solve. It's up to us to acknowledge his wisdom and to not give it, "matter," status as a substance or solution that it not only is not entitled to, but that Aristotle himself would have disqualified. He knew it for an unsolved problem. In his thinking it must remain so. We do him best by understanding him in and on his terms, which is to say that matter, as he conceives it, is a bit of smoke and mirrors. Pretty good smoke and mirrors, but them just the same.

Instructive fact-based correction invited.

↪Fooloso4 What do you think? — Wayfarer

Aristotle's use of common words always maintain that usage even when he extends the meaning. The term 'eidos' means the look or kind or essence or species of a thing. Form is also the term used to translate 'morphe'.

I do not think that Aristotle's aim is to provide a consistent definition of the term but to examine what is said and observed. That is why he typically begins by discussing earlier philosophers. He is not building arguments that lead to clear unambiguous conclusions and knowledge. He is leading the reader to think about these matters, to recognize that they are problematic, aporetic.

Those quotes I referred to make a very clear point: the material senses (eyes, ears) perceive the particular being, the intellect perceives the form. — Wayfarer

Computers can recognize forms (patterns).

Nope. One is material, the other intellectual. Otherwise, why is it ‘dualism’? And why doesn’t the soul simply die with the body? — Wayfarer

Have you not read Aristotle's On the Soul? He's explicit, sensation is a power (potency) of the soul.

I guess I just don’t see why conceiving of prime matter as pure potentiality is problematic. The concept seems fairly straightforward to me; I mean whatever exists materially must have the potential to do so, right? So that potential is prime matter. — AJJ

Prior to the existence of a thing, is the potential for that thing. But the potential for that thing exists as something actual, so this potential is not "pure", it is restricted by what actually exists. Pure potential would be infinite, and this is what is impossible to conceive of as being real. It can't be real, because as I said this would mean that at this time, when there was infinite potential there would be nothing actual. And if there was nothing actual, there would be nothing to actualize anything out of that potential, so there would always be nothing actual. But this is inconsistent with our observations that there is something actual. That's why it's impossible to conceive of, because it requires that nothing is actual.

Plotinus has it that the One, being beyond the constraint of ignorance, creates freely and not of some necessity beyond its control; an important distinction I guess, although it seems to me it amounts to the same thing - since to not create would presumably then be an error made in ignorance, and so not free, and so impossible. — AJJ

That's right, there is no principle which we can say "necessitates" material existence. One Form necessitates another Form, through a logical process (logical necessity), but no Form can necessitate material existence. This is an indication that material existence is caused by an act of free will, the love of God, or because God thought it was good.

And btw, the "what" referred to what Aristotle says about matter. It's right there above: "What is it he says...? So the question stands: what does he say about it? — tim wood

Actually tim, you said: "What is it he says explicitly matter is". This is asking what Aristotle said matter "is". AJJ answered that very well, with "potential". Potential neither is (being) nor is not (not being), that's why it is proposed as a means of accounting for the reality of becoming And since "potential" is other than "actual", and this is what "is" refers to, what is actual, it really doesn't make any sense to ask what matter is. Now you've changed the question to what Aristotle says "about" matter, and this is a whole lot of different things, in a whole lot of different places, and that's why your quotes from Stanford show such a variance. When we say "what" a thing is, we generally state some sort of definition. But when we talk "about" something we tend to say many different things about it, and it is not necessary that "what it is" is one of the things that we say about it. So we might entertain the possibility that there could be something (like matter), which has no "what it is".

Now I make a claim about Aristotle. He was operating with wrong presuppositions... — tim wood

OK, if this is the case, then you ought to be able to state these presuppositions which you believe Aristotle was operating with, and we can discuss whether he actual was or not, and if he was, we can determine whether your judgement that it is wrong is justified.

As a matter of the history of ideas, his conclusions are interesting. But they're not modern science. As noted above, his "matter" is that which not only isn't, but isn't even an isn't, and cannot even be asked about. it's a plug-placeholder for a problem that Aristotle encountered in giving an account that he did not solve and that he knew perfectly well that he did not solve. — tim wood

Of course he knew perfectly well that he didn't solve that problem (the problem of becoming), he proposed some principles, and a direction to move in. I don't see the point in your comparison to modern science. Physicists know perfectly well that they have not solved this problem either. Modern physics points us in a direction slightly different from that proposed by Aristotle. The fundamental particle "isn't", but this isn't isn't even an isn't, because the fundamental particle is something, it's a wave. OK, I see the point to your comparison. But since neither solves the problem, on what basis would you claim that one is wrong?

I’ve been confusing terms - I thought the active intellect was another way of describing the unmoved mover. — AJJ

While they are given independent accounts in Aristotle's writings, some commentators do consider them to be equivalent and that is one of the interpretive controversies.

So it seems to me on Aristotle’s view that universals must be ultimately grounded in the unmoved mover, rather, which is why I don’t fully understand the rejection of Plato’s Forms. — AJJ

Aristotle rejected Plato's theory of forms and replaced it with his own hylomorphic theory. But per Aristotle's description, the unmoved mover doesn't seem to be a hylomorphic or natural being. Which puts the unmoved mover in apparent tension with Aristotle's otherwise consistent hylomorphism and naturalism. So interpretation here is also controversial with different commentators providing a range of Platonic and naturalist accounts.

My own view is that the unmoved mover should be understood in terms of Aristotle's hylomorphism and naturalism and not in Platonic terms. That would be consistent with his rejection of Plato's forms.

My own view is that the unmoved mover should be understood in terms of Aristotle's hylomorphism and naturalism and not in Platonic terms. — Andrew M

Aristotle was a student of Plato, he was not educated in modern naturalism. And, he clearly refers to the difference between artificial things and natural things which was the convention of his day. In the attempt to establish principles for resolving this difference (which was a chasm of misunderstanding), he employed the concept of "final cause", "that for the sake of which", "the good", which is clearly Platonic.

I think the question would have to be asked, then, why Aristotelian philosophy is not nominalist. Because nominalism denies that 'forms' or 'types' have any reality outside the things which instantiate them; — Wayfarer

No, it is Aristotle's immanent realism that denies that 'forms' and 'types' exist in separation from particulars (though they can be considered separately).

Whereas nominalism denies that 'forms' or 'types' have any reality outside the people that name them. Ockham wrote, "I maintain that a universal is not something real that exists in a subject ... but that it has a being only as a thought-object in the mind".

Pure potential would be infinite, and this is what is impossible to conceive of as being real. It can't be real, because as I said this would mean that at this time, when there was infinite potential there would be nothing actual. — Metaphysician Undercover

Yeah, I see what you’re saying now and agree. To conceive of prime matter is to conceive of non-existence existing, which of course you can’t.

Aristotle was a student of Plato, he was not educated in modern naturalism. — Metaphysician Undercover

For Aristotle, knowledge comes from experience in the natural world.

Aristotle's immanent realism means his epistemology is based on the study of things that exist or happen in the world, and rises to knowledge of the universal, whereas for Plato epistemology begins with knowledge of universal Forms (or ideas) and descends to knowledge of particular imitations of these. — Aristotle - Wikipedia

My own view is that the unmoved mover should be understood in terms of Aristotle's hylomorphism and naturalism and not in Platonic terms. That would be consistent with his rejection of Plato's forms. — Andrew M

Interesting to consider how that might work.

Aristotle's immanent realism means his epistemology is based on the study of things that exist or happen in the world, and rises to knowledge of the universal, whereas for Plato epistemology begins with knowledge of universal Forms (or ideas) and descends to knowledge of particular imitations of these. — Aristotle - Wikipedia

I like the Aristotelian emphasis on the material, as opposed to the Platonic notion of the world being something we must ascend from; but I’m inclined also to think the world is an imitation of things higher than it - seems there’s enough ambiguity to hold to both approaches.