Few people are raised atheists, but I get the impression that many convert to atheism when they are teenagers or young adults (before they begin their careers), which could lead them to choose philosophy as their career, accounting for their overrepresentation as philosophers.
Is philosophy really that informed by science? Science is the study of the physical world. Philosophy is the study of the nature of existence. Because one person does two jobs does not mean they are related.
You said, "The historical pattern we observe is one of various mysteries being attributed to God, and then science providing a naturalistic explanation for a given mystery, and so God retreats to more distant mysteries. By our present day, God has retreated so far that he is beyond the bounds of the universe, where he is safe from examination by science." I'm unsure where you see this historical pattern. Perhaps in pagan religions, but certainly not in Christianity. You think too little of the philosophers and scientists of the past. God being defined as incorporeal and beyond the bounds of the universe is hardly new.
Thomas Aquinas way back in the 13th century taught that God was not within our physical universe, but rather incorporeal and omnipresent through holding everything in existence: "First, as [God] is in all things giving them being, power and operation; so He is in every place as giving it existence and locative power. Again, things placed are in place, inasmuch as they fill place; and God fills every place; not, indeed, like a body, for a body is said to fill place inasmuch as it excludes the co-presence of another body; whereas by God being in a place, others are not thereby excluded from it; indeed, by the very fact that He gives being to the things that fill every place, He Himself fills every place. . . . Incorporeal things are in place not by contact of dimensive quantity, as bodies are but by contact of power."
-https://www.newadvent.org/summa/1002.htm#article1
Certainly, according to the science of the day, some things seemed most likely to be moved by miracles, since there was no satisfactory physical explanation for them - like the stars being moved by the power of angels. But this is science, not philosophy, concerned with physical things, not metaphysical things. It was the science that seemed most reasonable at that time. As we have learned more about science, we see miracles are not necessary for the movements of the stars, but this has no philosophical consequences at all. The philosophy taught by the Catholic Church has never changed, only been more revealed over time - and we have not made many advancements since Thomas Aquinas.
If the experts in philosophical arguments who found the first cause argument unpersuasive had persuasive arguments to back their view up, then I might be convinced. Just now, I searched Google for disproofs of the First Cause argument, but found nothing that we have not addressed, and nothing that seemed to be written by a professional philosopher. This makes me think that these experts, despite their education and numbers, are, for whatever reason, not paying this argument the due attention necessary for them to see the truth of the matter. Even smart people, even in great numbers, often make decisions based on emotion instead of logic. That is unfortunately what all people tend to do. I'm glad you, on the contrary, are pursuing logic in this matter so earnestly.
You asked if I would lower my confidence in God's existence if the First Cause argument does not hold up. If you saw 100 roads leading to Rome, with signposts clearly marked, and then you find proof that one road leads to the desert instead, would you stop believing in Rome? Or lower your confidence at all? 1 road surely is not enough. Wouldn't you not first investigate about more roads? But I think this road too does lead to Rome.
Here is the crux of the argument: saying something is eternal is not the same as saying it exists by its very nature. Anything can logically be eternal. Only the First Cause exists by its very nature (since its existence alone depends not on anything other than itself). But why does something that exists by its very nature have to be logically necessary? Why is something being eternal not enough to explain it existing by its very nature?
(Remember, causality does not require time at all. In the argument that the simple fact that something exists for eternity means it doesn't need to have a cause, you are assuming that "eternity" means simply being in time forever, and that causality is strictly temporal. But we have discussed how eternity is outside of time entirely, and how even if we freeze and look at one moment of time divorced from all the rest of time (which is the best way to think of eternity), we still need a First Cause to hold everything in existence. For the existence of everything in frozen time still depends on the existence of the fundamental matter and energy that makes up the universe, which must either be the first cause or depend on something else for its existence.
And another clarification: below, when I am talking about logically possible omniverses, I am not talking about alternate universes in a multiverse - if that existed, then it would all be part of one omniverse, the sum of all things that exist. A logically possible omniverse is another way that all of existence could have been.)
Suppose a first cause exists by its very nature, in eternity. Suppose, also, that it is not logically necessary. This means that it is logically possible that this first cause could have not existed. Now let's imagine we are in this alternate possible omniverse where the first cause does not exist. But this causes a logical contradiction, for now we are saying that this first cause, which exists by its very nature, does not exist. How could it not exist if it exists by its very nature? Could it be that its existence explains its existence, and its nonexistence explains its nonexistence? By no means! For unless the first cause's nature suddenly changes; it cannot both exist by its very nature and not exist by its very nature. And if its nature changes, then it is a totally different first cause, and proves nothing about the original first cause. Then we would be saying that the original first cause exists by its very nature in one possible omniverse, and a different first cause does not exist by its very nature in the second omniverse. But how can something not exist by its very nature? Something that does not exist does not have a nature at all!
We have to realize the full extent of what it means for something to be the First Cause, to exist by its very nature. This means that its existence is not dependent upon anything - its existence is wholly independent, and must be so, for it is upon the First Cause that the existence of the entire omniverse rests. But if its existence is wholly independent, then that means that it exists no matter what, for its existence is not dependent upon anything. It's existence cannot be dependent upon whether we happen to live in the right possible omniverse - no matter what logically possible omniverse we might have lived in, the same First Cause must exist.
Therefore, the First Cause must be logically necessary, such that we cannot logically imagine the omniverse without it.
But why can the First Cause not be multiple different things? Why must it be such that we cannot logically imagine it to be different than it is?
Imagine that X is the First Cause in our omniverse. Now, if X could have been different then there exists in the realm of logical possibility an omniverse where Y is the First Cause instead. Since X and Y are both first causes, they both exist by their very nature. But this means that they hold themselves in existence, so they always exist in every logically possible omniverse, else their existence-by-nature would cause a logical contradiction. So X and Y both exist in both possible omniverses. But if each omniverse has two first causes, that means that only one of the first causes is logically necessary - the omniverse could easily be held in existence by only one first cause. Okay, so we have a necessary first cause, X, and an unnecessary first cause, Y, that both hold themselves in existence. But if one first cause, Y, is unnecessary, then there exists a logically possible universe where Y does not exist. But then Y cannot exist by its very nature, else it would exist in all universes. We have reached a logical contradiction - now Y must both exist by its very nature and cannot exist by its very nature. So Y must not be a first cause.
This proves that there can only be one First Cause, and that that First Cause must be such that we could never logically imagine that it could have been any different. This means that it has no potential to have been different. So it must be entirely without potential and entirely the opposite of potential - actual (as all humans have the potential to learn French but only some have actually learned it - only some have learned it in actuality). We can describe this First Cause that is entirely actual as Pure Actuality, Pure Being, or Pure Existence. This makes a lot of sense - what else other than Pure Being could hold in existence both itself and everything else in the omniverse?
Again, the argument from logical necessity proves that the laws of physics cannot be the First Cause, for they could logically be different.
Another disproof of the laws of physics as the First Cause -
How would the existence of the fundamental matter-energy that makes up the universe depend on the laws of physics (the First Cause must hold everything in existence always - so those fundamental particles cannot hold themselves in existence, for they exist in time)? The laws of physics aren't an actual thing that exists, they are simply descriptions of how things that exist interact. They have no existence to allow anything to depend on them. How something exists cannot possibly be the cause of its existence.
Now, it's time to move on to the First Cause's other attributes.
We can learn the rest of the First Cause's attributes from the First Cause's lack of potentiality. The First Cause must also be perfect. For if the First Cause lacked anything, the First Cause would be partly potential, not wholly actual. Evil is the absence of the good, not something that actually exists itself. This means the First Cause must be fully good.
Because the First Cause must be Pure Actuality or Pure Being with no potentiality and therefore no lack, the First Cause' every attribute must be perfect (wholly actualized), wholly complete and fulfilled. It must be personal, for we know a person is better than an inanimate object or force. It must be true, good, beautiful, omnipotent, omniscient, etc. - in short, it must be God.
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I apologize for the semantic confusion about simplicity. Let's try to end it. I propose "simple" = composed of less parts; and "complex" = composed of more parts. Do you agree?
So an amoeba is simpler than a human, and a human is more complex than an amoeba. I never meant to contradict this. Nota bene: however, an elephant is not more complex than a human just because it has more molecules. This is because these molecules work together to form parts, like organs, which are bigger than those of humans but not themselves composed of more parts than those of humans (an elephant's brain is not composed of more "brain-parts" than a human's brain).
I was saying that the "I" is composed of only one part. The reason why will become clear below:
There is some semantic confusion with "mind" I think as well. I propose "mind" = the "I" itself, or a self-reflective observer. A "brain" = the physical thing in our heads which allows the mind to operate a body in time and space.
You seem to be asking if I think the "I" is separate from a brain, or is an emergent property of a sufficiently complex brain. I most definitely think the "I" is separate from a brain, and I'm certain you think the "I" is only an emergent property of a sufficiently complex brain. Since you believe an "I" can emerge naturally from matter itself if the matter becomes complex enough through evolution, you believe that if a computer became complex enough it could potentially gain an "I". I don't believe an "I" can ever possibly come from matter.
A computer, even a self-learning one, can only ever make decisions based on how it was programmed to respond to external stimulus from its environment. This will never change, no matter how advanced computers get. How could this ever create an "I"? It has no free will; it makes choices according to variables and previous instructions.
We see that humans do have a free will. How could this ever come about from matter?
You said, "As we move back in time, we see capabilities becoming more and more primitive. But once we get all the way back to the ultimate beginning, suddenly we jump to the most advanced capabilities of anything ever?" This jump does not exist - remember that God is outside of time. There is no time before the creation of the universe where God was there alone. Time began with the creation of the universe. So God always exists in eternity outside of time and space - the chain of simplicity you outlined ends in the big bang, which presumably started with a very simple "point" of matter and energy. God, infinitely capable, exists outside of time and space, which is entirely logical with the scale of increasing capabilities you outlined.
You said, "I believe in the concept of justice, I just don't think it's objective, any more than the rest of morality is."
Wonderful! So if objective morality exists, then Justice exists and the idea of hell makes sense morally? So our discussion is already aimed at the answer!
(I want to add about hell - one does not necessarily have to philosophically run through systematic steps of reasoning to earnestly seek the truth. There are other legitimate ways to seek the truth.)
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