Ok, I finally have a few minutes so I'll take a stab at addressing the main issues in the causeless cause argument (this version of it). Fundamentally there are a ton of hidden premises baked into any abstract argument like this - I call it abstract because almost by definition it's not an
empirical deduction based on observations, but an argument from axioms only. So we must look at these axioms in order to see not only whether the conclusions follow, but why these axioms should be accepted in the first place. Otherwise we have two possible situations:
1) The axioms are reasonable,
but ultimately inaccurate, and so the theory is
consistent but also false.
2) The axioms are unreasonable, or undefined, in which case the syllogism becomes immediately suspect.
Part of the issues raised starting in the late 19th century is that language is a barrier that needs crossing before we can be certain what we're saying. It's not enough to use a term, but it has to be clear that person A and person B not only *think* they mean the same thing by it, but in fact DO mean the same thing by it; and moreover, that they are both not merely inventing something that is merely a figment of their imaginations. I think Plato and the Peripatetics anticipated the major issues involved in tackling the definition of a term. You can have a dialogue like the Republic ostensibly about trying to define "justice", but in reality it ends up being a discourse on how problematic it is
to even frame an attempt on the definition.
So let's start with a few of the axioms that
are stated overtly in the above schema:
1. The universe exists and is intelligible. That is to say, things exist and we can see that there are reasons for why things exist. Things don't pop in and out of existence for no reason.
Clause 1 "the universe exists and is intelligible" is the axiom here; "things exist and we can see..." is apparently an explanation, or elaboration, of what this axiom is supposed to mean. But the problem arises inevitably: how to define a tricky axiom without resort to terms that require even more definitional apparatus than the axiom does. One huge example of this becomes immediately apparent: what does it mean to say that "we can see" that "there are reasons for why things exist"? Who is this "we"? Is this really an axiom with a baked in principle that the following applies to
everyone by definition? And that thing that "we" can see is that there are "reasons" for why things exist. I can explain trivially why this is too much to bite off: I personally couldn't even agree that "I see that there are reasons for why things exist." In fact I have no knowledge
at all about why things exist. To use Hume's argument, the only reason I can even say they exist at all is through experience; it just so happens this is how it always was when I was young, and still appears to be now; but nothing in this suggests either a law or an explanation; just the mere fact itself that these things are there and continue to be there each day. This is a huge issue, because there is a potential limitation built-in to things about what I can say about them sight unseen. Pure reason cannot tell me
why things exist, even though empirical experience can make me used to the fact that they do. Before I spend an eon taking on axiom 1, let's move on for a moment.
2. If this weren't true, science and philosophy wouldn't function, and we wouldn't be able to trust our cognitive and sensitive faculties. But science and philosophy do fuction, and we can use reason and our senses to learn about reality.
The axiom is here is that science and philosophy do function; and from this we can gather some corollaries. But what does it mean to say they do function? Now if we're being informal we can say that the reasoning process seems to bear fruits; that much we can agree on. Engineering models work, and so forth. But it's not enough to say they work; this axiom requires that they work
specifically in such a manner that axiom 1 is justified. Axiom 1 says that we know the reasons why things exist; and so for axiom 2 to support axiom 1, it requires that science and philosophy work
because we know why things exist. But this is in fact not necessarily true. It is entirely possible for things to work for reasons we do not understand at all. Animals, just by comparison, have instincts that generate productive impulses. For examples, beavers can build dams; but this does not mean they understand why dams work, or even that they work. They just do the thing they're programmed to do because it's their heuristic and it keeps their species going. A sort of selection process got them here (if we believe the Darwinian story) but certainly not a chain of reasoning. Why should be assume our logic and scientific success is a result of 'true understanding' as opposed to just a series of heuristics that get results but for reasons we know not why? Whis "why" is the connective tissue between axiom 1 and axiom 2. Without it, we can't really say we 'know' why things exist, and we would be restricted into saying, as in the pragmatic school, we can get things to work in certain ways and our unstanding stops around there.
3. The explanation of the existence of any thing is found either:
a. In an external cause (in which case, the thing's existence is contingent upon that external cause), or
b. In the nature of the thing itself (in which case, that thing necessarily exists).
I was being specific about term use before to illustrate a point, which becomes absolutely central here in axiom 3. To my satisfaction, we have not yet established that we
do have the capacity to explain why anything exists, but nevertheless we are trying to trackle the problem of assigning reasons for that existence. I understand the desire to ask how things can be, but as with Aristotle, I find it highly problematic to assume we have all the possibilities at hand to list them exahustively (and the Aristotealian reasoning breaks down if you can show the lists are not exhaustive, because often it is really quite essentially that they are airtight and allow for no other possibilities). In this case two possibilities are offered. I can't say what I think of them because I don't know how "causing" works as axiom 3 seems to employ the term. Without knowing the mechanics of "causing" it's hard to me to agree that these are the only two possibities. In fact it's hard for me to even agree that these two listed
are possibilities. For instance, what does (b) mean, in clear an definable terms? How can a thing's existence be explained in the 'nature of the thing itself'? Without an example of this it's hard to see how this clause is definable. Like, what does it really mean, and how can we know that we are not just using words improperly?
4. We see contingent things all around us and we ourselves are contingent things.
I think if I'm tracking the chain of arguments, axiom 4 is really foundational for axiom 3, rather than the other way around. It seems that the working definition of 'thing whose cause is in its own nature' must begin with a statement of what that
is not, which is to say, all the stuff and creatures we see every day. So in order to put forward a definition of a self-causing thing, we need to first define what a contingent thing is, since these we actually see (according to the argument). But here is a funny, if unintuitive question: how do we actually know that all of this stuff is contingent? Contingent on what, and in what manner? Certainly we could
suppose that nothing comes from nothing (another, major, axiom), and so if there is something then therefore it came from or is supported by something else (the contingency). But that supposition seems to also suffer from a definitional problem, again, of what it means to say something 'causes' these things. And I'm being quite honest when I say I don't know what this term means. I am very familiar with this type of argument, btw, but what I see in them is they always take for granted certain things as being obvious which I think are not obvious at all. In fact, they are devilishly tricky because we want to feel like they don't require explanation. But this is a formal argument, and must be mathematically tight. We can't make use of "well everyone knows X" type assumptions.
The remaining axioms all essentially rest on axioms 1-4 being agreed upon, so I can stop here for the moment. Obviously if we had a clear and consistent definition of "contingent" and "self-caused", and moreover knew these were in fact 'real things' and not just made-up terms, it wouldn't be very hard to show how the objects in our world obviously require this contingency to rest on something. Whether that 'something' must be omniscient, etc, is IMO a totally other paper topic. I've seen proofs of the existence of God before, and typically they are very careful to avoid making any sort of statements about that God which are just re-interations of an extent faith system. So they define God merely as "that thing we are talking about which is an uncaused cause", and insist they are not
necessarily talking about the God of any particular faith. Obviously they actually are, but the argument itself is not, which is the point.
These types of approaches are really tempting, but always require we make positive assertions that are IMO above our mental pay grade. We don't necessarily have the apparatus to define causes all the way to the bottom, nor to understand what it could even mean to say a thing self-causes (or doesn't). Actually in Catholicism that's one of the mysteries (the trinity, essentially), which is to say, it's a thing that should be pondered but never explained because it can't be explained by us (according to that faith system). So ironically it's often an atheistic notion that all things are explainable, whereas some faith systems maintain that human knowledge has limits and our reasoning cannot breach certain boundaries. Just for instance, Buddhism and Catholicism are completely incompatible on this particular point, since Buddhism suggests we can attain perfect true knowledge, whereas Catholicism says that this is impossible.