Are you familiar with Kant's famous argument against the idea that time has beginning? If not, you can check out this wikipedia article on temporal finitism which mentions various versions of the argument and the objections of academic philosophers against it.
"An actual infinite cannot be completed by successive addition."
"The temporal series of past events has been completed by successive addition."
"Thus the temporal series of past events cannot be an actual infinite."
If we assume that the world has no beginning in time, then up to every given moment an eternity has elapsed, and there has passed away in that world an infinite series of successive states of things. Now the infinity of a series consists in the fact that it can never be completed through successive synthesis. It thus follows that it is impossible for an infinite world-series to have passed away, and that a beginning of the world is therefore a necessary condition of the world's existence.
— Immanuel Kant, First Antinomy, of Space and Time
I'm interested in seeing the our forumgoers' arguments against it (preferably as detailed as possible). Go ahead and exercise your wisdom.1. If the universe did not have a beginning, then the past would consist in an infinite temporal sequence of events.
2. An infinite temporal sequence of past events would be actually and not merely potentially infinite.
3. It is impossible for a sequence formed by successive addition to be actually infinite.
4. The temporal sequence of past events was formed by successive addition.
5. Therefore, the universe had a beginning.