The finitude of the universe makes a prior to the Big Bang almost inevitable

Introduction (A 0) Currently, there are two different theoretical frameworks to describe nature: General relativity, which is used for high masses and spacetime geometry, and quantum field theory, which is used at the smallest distances. Yet, when talking about the most extreme conditions of space and time - like the beginning of the universe - both general relativity and quantum field theory would be needed to correctly characterize nature. But as they are, they contradict each other, and a new theory of quantum gravity is needed to reconcile them [1]. Thus - as they both aren't valid for times shorter than the Planck time (definition see [2]) after the Big Bang - we cannot use either of them to be perfectly sure what happened at the time of the Big Bang or even before. Since there currently is no widely accepted theory of quantum gravity, the only foundations we can build our arguments on during this debate are logic on the one hand and those aspects which are true for both general relativity and quantum field theory on the other hand, as they will most likely be present in a combined theory as well. Argument 1 (A 1) The absence of a period of time prior to the universe necessitates a first state of time. A first state of time is physically impossible. Thus, there must have been a period of time prior to the Big Bang, as claimed in the resolution. (A 1.1) The absence of a period of time prior to the universe necessitates a first state of timeThe universe has only existed for a finite amount of time. That means, there must have been a first state of the universe and any particle to have experienced it must - at this time - have had a later state of time, but no previous. Consequently, time must have been non-differentiable [3] at least once during the existence of the universe, if there has been a beginning of time itself - marking a singularity at t = 0. (A 1.2) A first state of time is physically impossible In both general relativity and quantum field theory the velocity of a particle is defined with respect to a differentiable time dimension [4]. If a first state of time exists, for particles at t = 0 therefore the velocity is neither defined in general relativity nor in quantum field theory. Extrapolating from those theories, no current approach to quantum gravity bears a different definition of velocity. Judging from current science, all particles have had an undefined velocity at t = 0, assuming it was the beginning of time as well. However, this state was already included in our definition of the universe (D.1), and since for all times later all known conservation laws applied (such as the conservation of momentum and the conservation of energy), it follows directly, that all particles must have kept a completely undefined velocity until present, if they had one at t = 0 . Yet, this conflicts with observation. Note, that this argument does not conflict with quantum mechanics, where one cannot measure position and velocity of a particle at the same time with arbitrary precision, but upon a measurement of position the velocity is still defined in terms of a probability distribution [5]. At an alleged beginning of both time and the universe at t = 0, a velocity measurement performed could principally not give any value even without any measurement of position - there wouldn't even have been a physical probability distribution. Therefore, a beginning of time itself would be a physically impossible state. (A 1.3) Thus, there must have been something preceding the Big BangThe only and most simple way to account for presently measurable, defined velocities, is to assume the existence of time prior to the Big Bang. Thus, I conclude the existence of a period of time prior to the universe is almost inevitable according to current physics. Sources [1] . https://www.perimeterinstitute.ca...[2] . http://astronomy.swin.edu.au...[3] . http://en.wikipedia.org...[4] . http://hyperphysics.phy-astr.gsu.edu...[5] . http://www.princeton.edu...