According to many philosophers, both professional and amateur, the veracity of the cosmological argument, in its various forms, always hinges upon whether or not the universe began to exist. This idea is odd, though, since the two most famous proponents of the argument, Aristotle and Aquinas, did not hold that the temporal finitude of the universe could be rationally demonstrated. Aristotle, in fact, held that the universe did exist from eternity, yet it is his argument from motion that Aquinas adopted and used in order to demonstrate that God exists. Aquinas held that the world was finite, but this view was held in light of revelation, meaning that it is not logically contradictory to say that the universe began to exist in time, we cannot prove by reason that it did, though, and since revelation holds that it did then we are to believe it as well.
One of two things is happening here: 1) Anybody with common sense and who reads the argument with even the slightest diligence will immediately see a contradiction in the opinions of arguably the most brilliant philosophers who ever lived or 2) We do not understand what either Aristotle or Aquinas are actually saying. Which should we pick?