This is ridiculous. The universe doesn't create matter, the universe is matter. Not only that, matter and energy are neither created nor destroyed. Only 1 sentient species has the drive to comprehend the universe, that's humans. And even then, many humans have no interest in how the universe works.

If our will begins to exist, or changes, it must be "changed by another". That means it cannot be changed by itself, but another. If our will is changed by another, and whatever changed that is changed by another, and so on, you get a chain of causation going back way before we were born, and that is essentially the same thing as determinism, which is incompatible with libertarian free will. So Feser's traditional Catholic view requires libertarian free will in order to make sense, but it also denies it. Hence, his worldview is self-refuting.

I will make two final brief remarks.
First, that is part of the key question although less fundamental. I see the key question as "what is the source of the universe's existence?" or "why does it exist?" Each of these sort of branches off into "why not no universe?" and "why this universe rather than another one." To me, the only answer that I see as possible is in a being which cannot fail to exist or be any other way. That being is necessary and absolutely fundamental and completely intelligible. That being is what I call God.

Second, as for separate religions, at least as far as monotheists go, I think that they have the same answer to this question. The difference lies in what additional information God has revealed (e.g. in the Bible or Koran?)

Thanks for the discussion as well. It was very thought provoking!

The key question appears to be "Why is the universe the way it is and not another way?" My answer is that I don't know. Maybe I will never know. The question may be too big for the human brain.

Some people say God, some people say that there is no answer. I'll wait and see. Maybe one day more definitive evidence will be discovered. Maybe the Christians or the Muslims will be able to point out that they were right all along.

It's uncomfortable not knowing, but it's better to not know than to start with an answer before looking for one. I'm not saying you are doing that. I'm saying that, if I just decided to believe in God right now, I would be doing that. Just making up an answer without figuring it out first.

Thanks for the discussion.

(1) I don't see how a possible cosmos can make itself actual. To be a cause means to have the power to bring about an effect. Something merely possible has no causal power, except insofar as it is actualized. The reason is being possible just means logically coherent. If a physical reality is logically coherent, this alone can't explain why it is a reality. As Stephen Hawking put it* “[The unified theory] is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?" I think the point can be applied to anything at all- Standing alone, it is just a description (whether it be mathematical or otherwise). Isn't that what a possible world is after all? So a description can't make something real.

*I use his quote not to argue form his physics expertise, simply because I think the quote is a very good one.

(2) I don't know enough to say. However, anyone who does have an educated opinion on the matter and is not a physicist relies on what he knows from physicists rather than any amount of his own personal study. Second, whether or not God exists and whether or not string theory is true each have different implications. If God exists, obviously it is possible that we are morally accountable to Him. Even if the existence of God was primarily a question of academic investigation, even if few people actually cared, it would not be on par with string theory because if God exists, He might want something to do with us.

(4) My problem with circular explanations is not with the time element. I accept the eternalist philosophical stance when talking about time. So I admit that in theory some weird time-travel scenario might be possible (I can't say for sure, and definitely can't say if its physically possible). My issue is that as an explanation it doesn't explain much. Using ur Fur Elise example, the question of "what is the source for the idea of Fur Elise?" remains open and unanswered. This is related to the question of "why is it not a different melody?"

You can answer with another mind, its necessarily that way, etc. Those are all possible. What is not possible, and the reason we got on the discussion in the first place, is that the circular explanation is a complete explanation. That is what I would deny.

As it applies to the cosmos: even if the physical universe in some way can go back in time to start itself off, it cannot be the source or explanation of its own existence. This is part of what I was getting at in (1).

(1) There may be something internal to a possible cosmos that might make it more or less likely to be actualized, for example if our actual cosmos started itself.

(2) Do you think string theory is accurate? Must someone have a degree in physics in order to have an answer to that question? My own opinion is that, no, anyone can answer the question. But the question is largely academic. It won't change someone's life much whether they accept string theory or not. It doesn't seem to change my life much whether I accept that this kind of God exists or not.

(4) I agree that it's circular. I don't see a problem with that kind of explanation, so long as it's self-consistent. For example, maybe I go back in time and show Beethoven his Fur Elise composition. Then he copies it and claims it as his own. How did I get the composition? From Beethoven. How did Beethoven get it? From me. I see this as a completely satisfying causal explanation for Fur Elise, but most people wouldn't agree. Maybe it's different intuitions about how these things work. Time, as I imagine it is just like another dimension of space, but with some geometric properties that we interact with in different ways. If someone or something could go back in time, it's like explaining a circle versus a line. People are more satisfied with line-explanations (Beethoven wrote Fur Elise) than circle-explanations (no one wrote Fur Elise; Beethoven got it from me and I got it from him) because they live on lines.

Now, that doesn't satisfy why Fur Elise and not a different melody. I don't know that. But it might be that it had to be Fur Elise because there was no other possibility. Or it might be because of God or some extratemporal agent. Or there might be no answer at all. Or something else. Who knows?

(1) As for your first question, what I mean is that everything is either metaphysically possible or not. If it is, it exists in some possible world. If it is not, there are no possible worlds which contain that thing. The same applies to the cosmos. Given this truth, there is nothing inherent about any possible cosmos which could tell us why it is actualized, because qua possible cosmos, all are the same.
To your second question-we would have to start by determining what kind of thing could actualize a possible world yet not be part of that world.

(2) Yes they do have those discussions although I don't think people without the background in physics can make judgments on the matter.

Our discussion on point 3 did illustrate that there is a philosophical side to the issue that can get deeper. I never denied that. What my initial point was that learning about the arguments for God's existence and making judgments about them was not only an academic pursuit in other words, they could be explained and understood to a degree even if one hasn't studied philosophy extensively. (This does not necessarily apply to all arguments. Maybe less so in the case of the argument I was referencing here. The main idea behind this one though is that something composed of parts is not the most fundamental type of thing that exists. Just like a cell is a more fundamental unit of life than the nervous system or an entire human being. This would consequently rule out the cosmos as the fundamental type of thing).

(4) Well going back to my example about being tired from a few comments above: does that work?
I would say it wouldn't because its circular. Would you disagree?

I think this post will simplify our discussion somewhat. If you disagree, you can choose one of the elements of our discussion, and we can talk about that. We've gone from (5) points to (4), and I hope this response will bring (4) points to (3).

(1a) You wrote:

the important thing with asking why this possible world rather than another is actualized is that since every possible world in itself is equal in its ontological standing as a possible world

What do you mean by "ontological standing"? Why are all possible worlds equal in "ontological standing"?

Since we don't know to begin with how our cosmos is set (or even much about what our cosmos is like), it doesn't seem as though we can be sure that the answer doesn't lie in the cosmos.

(1b) You wrote:

if there is any explanation at all why one is actualized and not another, it must lie in something external to the possible world.

Maybe the explanation is outside the cosmos. In that case, how will we determine what the possible explanations are, and which explanation is the best explanation?

(2) People without scientific backgrounds have discussions on string theory all the time. And I think (3) illustrates this point. I did not understand anything of your answers to (3a), (3b) and (3c). We can talk about God's existence, sure, but any real understanding requires a lot of work and study. Assuming that you understand what these answers mean, and I'm happy to think you do, it doesn't help me much unless I put in the effort to, say, try to find out how you know that God's nature and will are distinct, how they are distinguished, why his will doesn't also have to be the same, and how all of this fits with the idea of a fundamental entity (it doesn't seem very simple or fundamental to me).

(4) This is an interesting point, and may suggest our intuition diverges. The circle exists because A causes B and C, and B goes back and causes A. I've never thought that there need be any further explanation for A and B, except that it doesn't answer the question of why this way and not another. It's possible that God is the answer, or that some other external entity or principle is the answer, or that there is no answer, or that the answer actually lies in the circle itself: maybe it's the only logically possible way things can be, for reasons that would become obvious to us if we knew everything.

(1) the important thing with asking why this possible world rather than another is actualized is that since every possible world in itself is equal in its ontological standing as a possible world, if there is any explanation at all why one is actualized and not another, it must lie in something external to the possible world.

(2) the idea is that people without philosophical background can have intelligent and meaningful views and conversations about the arguments for God's existence without necessarily having found definitive proofs or answered every objection. "Trinity" etc. are certainly not common sense questions. My initial claim was that the arguments for God's existence had an intuitive dimension to them and were not only interesting as academic pursuits.

(3) back again to the initial point- it was not to defend every aspect of the argument based on the unconditioned and conditioned realities. Fr. Spitzer takes a number of chapters to do so. The initial point was just to recognize that things which are composed of parts are less fundamental than their parts. Hence, something composed of parts can't be the most fundamental thing.

As for each of your questions, I can give a short answer.
3a- A fundamental entity, being not composed of parts, would not be distinguishable from another one hence there could in principle be only one. If by asking "why could that only be God?" I am not sure what you are saying. I would say that God by definition is the most fundamental being. What other attributes God must have besides being fundamental are the next question.

3b- Fundamental entities would be by definition the most fundamental kind of thing and therefore, self-explanatory. As it relates specifically to this argument, the fundamental things have "unconditioned being." This means that no conditions must be fulfilled in order for the thing to exist. This entails that it exists by necessity. So the explanation lies in its own nature.

3c- If you are talking about God as understood by classical theists (and thus Catholics), then you are correct in holding that God could not have been other than He is. However, God could have chosen to not create the world or to create another. The reason lies in the fact that the immediate object of God's willing (e.g. creating this universe) is distinct from His ability to will and thus from the Divine Nature. I must qualify this statement by adding that traditionally, the ultimate object of His will which is the manifestation of His goodness is in fact willed by necessity. That's not terribly important however for the discussion at hand.

(4) Each member of the circle is explained individually in the sense that asking "why?" for each member of the series has an answer. However, as a whole, the circle remains unexplained. I think that my example given in my last response illustrates the problem with an explanatory circle. Put another way, while each member of the circle is explained, why there should be a circle to begin with is left unexplained given that there is no source of explanatory or causal power in the circle.

(1) I agree that explanation is better to ask about than cause, or at least it's a more natural word to us at present.

Then you ask:

Since only our possible world is actualized, this raises the question as to why this possible world rather than another?

I don't know.

(2) I don't think common sense has much to do with "existence", "essence" and "divine simplicity", let alone "Trinity" and "hypostatic union".

(3a) Maybe there are several fundamental entities, a bunch of atoms, say, and none of them has a cause? Even if there is only one fundamental entity, why think that it is God?

(3b) Do you think fundamental entities require no explanation?

(3c) If a fundamental entity is such that it cannot be other than it is, is God really a fundamental entity? Could God have made different choices than he in fact did?

(4) I fail to see why the circle isn't well explained in terms of efficient causes (if you simply ask "what caused x?" I can always give an answer). But maybe you are talking about answering the question Why A B -> C and not something different? If this is the question you are asking, see my answer to (1).

(5) You say:

...in many cases maybe that is correct that people who ask that question don't misunderstand the argument. However, in many other cases I think that they do.

I agree.