A possible loophole is a causal loop - but I would see that as an example of an infinite regress, which also asserts a finite number of events. Worst of both worlds.
Casual loops have never been a problem. It’s not like we just discovered them
You are speaking here of accidental and temporal causes, but there are also ‘per se’ cuases.
While accidental causes might ‘loop’ essential causes cannot and a loop of accidental causes still needs an ‘outside cause’, since it still is a contingent system which cannot be its own cause.
The laws of logic, far more than the laws of physics, are time reversible!
I think that makes little sense.
To say that the ‘laws of logic are time reversible’ is an incredibly vague and pointless statement, I think.
Logic is understood as the study of correct and coherent reasoning and applied often to serach new ‘truths’ through inductive or deductive resoning.
The laws of physics are models that describe reality (also in time) and when we say thay are time reversable we mean that:
1 For classical deterministic physics (but also in Quantum physics, although quamtum physics has a broader symmetry, the Charge-Time-Parity symmetry):
when ‘reversing time’ (i.e. making a certain physical system go into the opposite direction) the same equations and laws will apply (like in a chemical reaction A + B <–> C + D, for example where we have the reaction A + B → C + D and the reverse C + D–> A + B… or another example are a thermodynamical system, where you varies the temperature, for example, or the absorption and release of a photon by an electron in an atom in quantum mechanics)
The implications of time, and especially Charge-Time-Parity symmetry, is that one could theoretically have an ‘anti-universe’ that would have the same laws as ours, but with opposite parity, time (it’d run backwards) and charge (made of antimatter).
2 For stochastic (ie random) systems, it means that if we have 2 states A and B, we cannot determine which came first.
Yet this, more than ‘time reversable’ means rather
‘mathematically reversible’ regarding a certain variable in an equation (time in this case), since it implies that the laws of physics hold both in a certain process and it’s reverse.
Now this whole discussion is mostly meaningles when talking about (pure) logic, since logic in itself does not describe (mathematically) a certain event (like an electron absorbing a photon anf going to an higher allowed energy level) but it is far more abstract (and of course it can be applied to math and physics).
If your aim was to try to create a symmetry between infinite regression and infinite progression, than you fall flat on your face.
Since I have yet to see the explicit argument against what you call regressus ad infinitum, I can’t argue why that should apply to progressus ad infinitum - all I can say is that I can’t see why it shouldn’t.
Basically because
regressus ad infinitum violates logic (and physics) itself. Think about it.
If everything has an accidental cause then the system either has a beginning or is “looping”.
Yet even if it is looping, there still the problem of per se causes, which MUST have a beginning somewhere and cannot regress infintely. A looping system must also be infintively stable: in nature there are no such systems due the second law of thermodynamics… even WORSE for a fully isolated system, such as the universe might be!.
So if there is an isolated universe, multiverse or ultraverse (whatever!) and we assume that the laws of physics (especially fundamental ones like the thermodynamical laws) still hold, then there can be no ‘looping system’ at all.
So PHYSICS seems to point out that there can be no looping system (a problem, among others, with the ‘big bounce model’ of the universe was indeed violation of the second law of thermodynamics.)
LOGIC: allows for a looping (or even infinitively regressive) ‘per accidens’ series of causes but looping or infinitely regressive per se causes are impossible and even if you have a systen with infinite per accidens causality (which is quite improbable as physics shows) it still would need a first per se cause at the origin of all.
A simple example: a particle going in circles: even if it goes or went in circles forever, it would still need a per se cause, in this case a material cause of the particle existing itself. It would make little sense (or no sense at all) to just claim ‘it has no cause’ (this does
not mean the cause must be temporally antecedent to the particle going round and round)
Hence the burden of proof falls on you to prove that can even theoretically existe a “regressus ad infinitum”…
And no, the fact that progressum as infinitum might exist, does not conclude that regressus ad infinitum also exists, they are not symmetric, as I said above.