One way to infer, that had to a be a before the Big Bang, is the 2nd law of thermodynamics The 2nd law states that the entropy of the universe has to increase. While an increase in entropy above absolute zero, causes a lowering of universal free energy via the equation G=H-TS, where G is Gibbs free energy, H is enthalpy, T is temperature in degrees Kelvin, and S is entropy.
A finite universe, like our own, with -ST (S increasing via the second law), will use up the free energy of a finite universe in a finite time. There is a beginning and end. If the universe was infinite, one would have an infinite time, entropy based, free energy bleed, loophole. Our universe is not known to be infinite if it starts as a singularity.
However, in the realm where space and time are both independent and not tethered as space-time, there is no energy, since you need distance and time or wavelength/frequency, tethered like space-time. In the realm where you have independent time and independent space you will have wavelength without frequency (not tethered) and frequency without wavelength (untethered). This is a place of infinite entropy, where independent space and time, can kiss (for various intervals, but not sticking), except for our finite space-time universe. The other realm is sort of virtual reality within a realm of time potential and distance potential; kisses, at infinite complexity. It will look void from a space-time POV, until one reaches into the quantum state.
That realm appears to be the drive behind the 2nd law in our space-time based universe. The energy from our universe, that constantly goes into increasing entropy, due to the second law, that is bled from the universe (is net gone), goes back to where we came. The energy is untethered and then flows back to the virtual void of endless possibilities. The untether photons also increase entropy.
We can thank Heisenberg for his uncertainty experiments, that show separated space and separated time at the quantum level. I can be thanked for the proper interpretation of his experiments. Physic left the golden age of Physics after that blunder of interpretation. The inverse relationship between space and time (position and speed), observed by Heisenberg, is not random, but a type of rational conservation effect within separated space and time. Being infinitely complex; S=infinity, and not finite, places conservation limits in other ways.
Say we wanted to make a new space-time universe. All we need to do is tether sufficient independent space and time. This will lower the entropy and release energy at the point of tether; Boom! Time potential is like the glue that defines the duration of the kiss.
