What I'm saying there is the fact that enables multiple possibilities. So why wouldn't that be an explanation? What other sort of thing would you be looking for as an explanation? — Terrapin Station

If I asked you for an explanation why it rains sometimes and you said “because there is a fact that enables there sometimes to be rain” then you’re not explaining anything - you’re just agreeing with me that there is indeed something called rain that happens sometimes.

I explain possibilities by positing abstract objects called possible worlds, with this world being a manifestation of some of them. Obviously you can’t offer the same explanation - yours must be grounded in the material world because you’ve stated you’re a nominalist and a materialist. So if there is a possible world where this planet doesn’t exist, you must appeal to something in the present world which materially contains that possibility - if there isn’t anything then it doesn’t appear you can coherently say on your terms that such a world is possible.

What else would we be doing if we're explaining what possibilities are/how they obtain? — Terrapin Station

So you’ve explained that possibilities are possibilities (how things could have been), but you haven’t as far as I can tell explained how, on your terms, they obtain.

As I mentioned above, I'm not a realist on laws of physics. — Terrapin Station

I know - I addressed this by inserting the “(however you understand them)”. I’m asking about a possible world where everything behaves very differently, and how on your terms that possible world obtains.

I can try another example: If for example there’s a possible world where this planet doesn’t exist, how on your terms does that possibility obtain? The answer to the effect that it’s there and we can talk about it has been covered already.

It seems to me what you’ve said there is to the effect that “possibilities obtain because there are possibilities.”

If for example there’s a possible world where the laws of physics (however you understand them) are radically different from the ones we have, how on your terms does that possibility obtain? That it’s there and we can talk about it isn’t a response I’m very willing to accept.

How on your terms do those possibilities obtain?

On my view, possible worlds are a way of talking about the simple fact that not everything about our world is strongly/causally deterministic. — Terrapin Station

So on your terms (as I understand them) a possible world would be a concrete abstraction in your brain, and so only a possibility so long as it existed there or in another person’s brain.

So we can't do possible worlds unless we buy platonism or god? — Terrapin Station

You can to an extent. But if you’re a nominalist about possible worlds then they must depend on the world around you and not be abstracted from it, which makes possible worlds such as one where the laws of physics are entirely different from ours impossible to have been.

If you’re a conceptualist then possible worlds can exist in the human mind, but then possible worlds where humans don’t exist become impossible, since if you rewound time to before the existence of humanity that possibility would disappear (as my own understanding has it).

So then, for one, in this context you'd be saying that possible worlds are objective thoughts or ideas? What would that amount to? — Terrapin Station

It would amount to there being either a Platonic third realm where those objects exist, or a divine intellect where they do.

“existing in thought or as an idea but not having a physical or concrete existence”

You'd have to explain how "discrete abstract" makes sense to you (unless you're simply using "abstract" as a synonym for "nonphysical," but I explained why that doesn't work). — Terrapin Station

I’d say possible worlds are abstract according to the definition I quoted, and they’re discrete because they can be differentiated.

They're abstract in terms of content, or in terms of semantics (meaning). Content-wise, they range of a number of particulars. That's the whole function of concepts. — Terrapin Station

Well I’d want to make a distinction then between an “abstraction” and an “abstract object”. The former being applied more generally to concepts that may actually be physical in nature, and the latter applying to those objects which fit the definition of abstract I quoted.

They do not necessarily reject abstracts as concepts. Hence we have conceptualist nominalists (which is what I am). — Terrapin Station

I’d say the definition in my OP recognises that.

Abstracts range over multiple instantiations of particulars, whether they're types/universals or concepts. — Terrapin Station

I don’t see how this applies to possible worlds, which I take to be discrete abstract objects.

if you believe that abstracts are concepts, you believe that concepts are events in a specific individual's mind, and you're a physicalist on mind. — Terrapin Station

In that case concepts wouldn’t be abstract, rather they’d be concrete.

(And likewise, "abstract" doesn't imply "not material.") — Terrapin Station

And I Googled abstract and this is the first definition given: “existing in thought or as an idea but not having a physical or concrete existence”.

I already explained the alternative. One can simply posit nonmaterial particulars. "Not abstract" doesn't imply "material." (And likewise, "abstract" doesn't imply "not material.") — Terrapin Station

If you edit your posts after I’ve replied to them I might not see the edit.

Can you tell me the difference between a nonmaterial particular and an abstract object such as a possible world?

What part of "nominalists DO NOT say that possibility must be grounded in the material world" don't you understand? — Terrapin Station

If possible worlds have been rejected as existing in the abstract then possibility must be grounded in the material world. So for example the possibility that it’s going to rain would instead be a description of the black clouds in the sky, say.

It says no such thing as "possibility must be grounded in the material world." — Terrapin Station

Your objection was that the definitions say nominalists are necessarily materialists. Being nominalist about possible worlds doesn’t mean being a materialist, it just means being one about possible worlds since they’ve been rejected as existing in the abstract.

The definitions, for example, say that nominalists are necessarily materialists. This is wrong. — Terrapin Station

Where does it say that?

Sure, I did a moment ago:

Nominalism comes in at least two varieties. In one of them it is the rejection of abstract objects; in the other it is the rejection of universals. Philosophers have often found it necessary to postulate either abstract objects or universals.

Like I said, I understand you can be nominalist about some things and realist about others. The definitions given in the OP are correct for the purpose of the point being made. I can at least concede that realism being true about possible worlds wouldn’t make it true about other abstract objects or universals, although it may as well be given the implications of that (the existence of a Platonic third realm or a divine intellect).

On Googling conceptualism you get this philosophical definition: “the theory that universals can be said to exist, but only as concepts in the mind.” Then from the Wikipedia page: “Conceptualism is anti-realist about abstract objects”.

On Googling nominalism you get this philosophical definition: “the doctrine that universals or general ideas are mere names without any corresponding reality.“

Those seem to me to match the ones I’ve given from Feser’s book, which seem fine for the point being made. I understand you can be a nominalist about certain things while being a realist about others, but nominalism or conceptualism about possible worlds appear to have the implications I described.

Hm, a square circle isn't nothing, rather it is an object that is both square and circular. Their existence seems to be impossible. But I think a truly omnipotent being would be able to create one, for nothing is impossible for a truly omnipotent being. — Bartricks

And I’d say something that isn’t a possible thing is no-thing: impossible thing = impossible to be a thing = no thing = nothing.

But I think that may be beside the point, since God is omnipotent by virtue of the fact that everything that exists derives its being/powers from him. If a burning torch was the only logically possible thing that could exist then its being (which entails the powers to give heat and light) would be derived from God, who would be able to create them infinitely and so be all powerful. Or, come to think, I guess he would be omnipotent even if only one burning torch was the only logically possible thing that could be created - since all the power in existence would all the same be derived from him.

Surely being unable to do the impossible is a restriction? — Bartricks

I think the problem with that is logical impossibilities such as square circles or whatever aren’t things - rather they’re “no-thing”. So what you’re really saying there is God is restricted by his inability to create nothing.

It seems the most powerful descriptions of God are those made by the Aristotelian argument from motion or the Neo-Platonic argument from composition, to give two examples. Both get you to a purely actual actualiser (the ultimate ongoing source of everything) to which you can add for logical reasons the divine attributes of immutability, eternality, immateriality, perfection, goodness, omnipotence, omniscience and intelligence. To be an atheist for intellectual (as opposed to purely emotional) reasons it appears to be those descriptions you’re (speaking generally) up against in providing refutations, or at least compelling rebuttals, of theism.

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.

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.

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.

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.

Sure :up:

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.

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

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.

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.

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.

Sure, it’s what allows there to be material objects in the first place and also what allows them to change.

So in his Physics, Aristotle wanted to be able to explain what we all observe, and say, that a thing remains being the same thing despite the fact that there are changes to it. Matter is the underlying thing which persists, and does not change when a change occurs, and assuming the reality of matter allows us to say that the same thing persists from one moment to the next, but it changes. — Metaphysician Undercover

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?

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.

The world isn't grounded in the active intellect for either Aristotle or Aquinas. — Andrew M

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

Thanks, that’s clarifying. Although it does still puzzle me why Aristotle would ground abstractions only in the world when the world is grounded in the active intellect - can you tell me where in particular Aquinas or others wrote about that?

The divine intellect is the ongoing source of everything I should say; that’s what the Aristotelian argument from motion establishes.

It’s both Aristotle’s and Plato’s idea. The divine intellect is the unmoved mover in Aristotle’s metaphysics, the beginning of everything. In Plato’s metaphysics, as interpreted by Plotinus anyway, the divine intellect emanates Soul, which creates and organises the world by reflecting on the divine intellect.

If the divine intellect creates the world then all the forms things have must come from it.

"prime" matter? Is prime matter different from matter? — tim wood

“Prime matter” is to my understanding the term for matter apart from an instantiating form.

That is, that matter, or prime matter - It - does not exist at all. And this is what I have seen represented as Aristotle's idea of matter - except that Aristotle apparently did not have a lot to say about matter, and such views are thus made up - inferred - from what he did say. — tim wood

That’s fine I’d say; it’s appropriate to refer to those interpretations that lend the clearest insights.

Is the Scholastic view similar? In a much as the Scholastics held that universals possessed an extra-mental reality, it seem likely that they probably held that matter existed. — tim wood

That definition I quoted is from a book on Aquinas, so I guess it is the Scholastic view.

Above as well we have the compatibility of The Forms, and form(s). If the forms are of the world, and The Forms are not, but are ideal and perfect, and the world is imperfect and imprecise, then how exactly are they compatible? — tim wood

Sure, but what I don’t understand is why the forms on Aristotle’s view shouldn’t also exist perfectly in the divine intellect, where it seems they must originate.

There is, however, a clear distinction between reading Aristotle and reading what other people say about Aristotle. — Fooloso4

This is the distinction I was describing, where what other people say about Aristotle is interpretation in an attempt to gain the best insight.

Or perhaps their interpretation lends the clearest insight.
— AJJ

That is possible but how do you know it is the clearest insight without reading Aristotle? — Fooloso4

I didn’t say I knew.