Actual infinities.

[Jehanne]

Physics, via QFT (Quantum Field Theory), which consists of QED (Quantum Electrodynamics) and QCD (Quantum Chromodynamics), explains the strong and electroweak fundamental forces of Nature, while General Relativity provides a classical description of gravity.  There is simply no need to posit anything beyond this, even if it is the case (and, it is) that certain phenomenon (such as all of biology) are not reducible to QFT or GR.

I am quite sure that they explain well the fundamental aspects of nature. My question is whether or not they account for the necessary being inherent in nature? Whether infinite into the past or having a beginning, something about the cosmos must just "be" as self-explanatory. Does physics describe anything like that?

Here's the Quantum Eternity Theorem from Quantum Mechanics by David Griffiths, 2nd edition (pages 13-14):



It implies that the Cosmo's wave function is eternal, that is, without a beginning or end.