> It's inconsistent to state that we believe that the Big Bang theory is a theory about the origin of the Universe and in the same time state that before some p

> It's inconsistent to state that we believe that the Big Bang theory is a theory about the origin of the Universe and in the same time state that before some point in time we don't know what happened. If that rule were in force, mathematics would disintegrate because it's built on a foundation of axioms. But scientific theories are often predicated on axioms whose consequences are examined, but whose existence are accepted without explanation until a more encompassing, more global, theory is created. Like relativity replacing Newtonian gravitation -- the new theory still has axioms, but the theory explains and encompasses more. > If we don't know what happened before some time t, then we don't know the origin, by definition. A scientific theory is by definition a testable, falsifiable explanation of what can be observed. For each such theory, there are limits to what can be observed. > Back then it very much is possible the Universe was still infinite in space anyway ... Yes, unless (imagine time running in reverse) spacetime collapsed to a point, as is often claimed, and as relativity theory requires. In that case, an infinite universe would occupy no space or time at all. The notion of infinity doesn't require infinite size.