Several people have in some way suggested to me that my problem with the cosmological arguments are easily resolved if I just accepted Aristotelianism, and after all, I should have if I was a Catholic at all to begin with. To the first point I would say, sure, cosmological arguments can be sound if the principles of Aristotelian metaphysics are accepted, but I have no good reason to think them all true. To the second, I disagree: despite comments from Popes defending the importance of Aristotelian-Thomistic philosophy in Catholic theology, nobody could possibly claim with intelligence that such comments are de fide. So their rejection is not heresy (cf. CIC. c.751). It is also manifest that such comments were not infallible acts of the papal magisterium, so canon 750 does not apply. What does seem to come into play is canon 752, which stipulates religious submission for papal exercises of the authentic magisterium (also those of the college of bishops, and c. 753 makes similar provisions for a bishop or collection thereof as such). But I have previously had such religious submission. This is giving the rather generous assumption that every time a Pope puts pen to paper in a teaching document, they are exercising this magisterium authentically.
I view Aristotle's metaphysics as one way of making a formalised view out of intuitions about the world. I have drawn the analogy in the past between his natural philosophy and metaphysics, and people have been quick to point out that they are distinct fields; that may be, but Aristotle employs the same approach to both, it is simply harder to falsify metaphysics. Once Galileo has the idea of putting to experiment Aristotle's doctrine that heavier objects fall faster than lighter ones (a pretty common sense notion) it becomes clear that it is false. Anybody can do the experiment. However something more philosophical such as Aristotle's direct realism is still defended by a tiny minority, even though it is pretty standard to refer to it as naive realism, owing precisely to its naivete.
As I think I have made sufficiently clear, I reject basing any justification of knowledge on intuition. Our intuitions about how the world works, as evidenced by both psychology and physics, are absolutely terrible. Humans see agency, meaning and patterns where there is none, we anthropomorphisise to no end, have a hard time believing things we strongly want to believe are false, are absolutely terrible with probabilities ... I could go on for a long time more with our rational defects and biases. Even if we lacked those, our brains think in such a mundane way that our only hope to understanding how the world fundamentally is physically is to fall back on mathematics (which proceeds by strict logic) and endure physicist's perpetual polite apologies for not being able to put four dimensions on a graph. Or not showing all of Hilbert space. I do not like to play the quantum weirdness card, but if there is one thing it illustrates is just how far reality is from our intuitions. Things do not work as we think they do. Things are not obvious. So principles which seem common sense and obvious cannot be justified on those grounds.
I reject Aristotelian metaphysics because its basis is intuition and not evidence. This is not a rejection of logic: if anybody can show that a metaphysical principle follows logically from a principle of logic, then it is logically true and I will believe it. But Aristotelian metaphysics is not an enterprise of pure logical argumentation, it smuggles in human intuitions all the time.
This might seem like a strawman to someone who finds Aristotle unituitive so I will offer an example of what I consider a major flaw with Aristotle's conception of the world, one which affects his cosmology, his physics and his metaphysics: Aristotle's view is teleological. Everything is about the endgame. Why do things fall? Because they want to get to the centre of the earth. Why do planets move in circles? They want to. And metaphysically, what is one of the four causes of things? What they are wanted to do, or its final cause. How do we know this is true? We do not. We just normally think of things in terms of it's purpose, so Aristotle made it into its own metaphysical principle.
If you think the world has final causes, prove it. If you think substance theory is the best way to think of the universe and its constituents, good for you, but don't expect me to believe arm-chair pontifications about them without demonstration. I do not even think Aristotle is necessarily wrong, but nothing is true because of Aristotle's fiat.