Matter and energy can be past-eternal

[Alex K]

I don't know, but it is quite plausible. But you started with the past eternal thing.5

What are your arguments and evidence for thinking it's quite plausible.

If you turn back time you get to a very dense and very hot state, and before that, either something like inflation or something alternative. When you turn the clock further you can run into singularities, but these do likely not exist in quantum theory and are just a sign that the classical theory becomes invalid. Quantum theory is expected to smooth these things out by virtue of the uncertainty principle etc, and if one then turns time back some more, what can happen other than going away from this extreme dense state again, i.e. entropy rises. The laws of nature are almost exactly the same backwards and forwards, so I'd expect that something similar can happen going back than when going forward.