Does a beginning necessarily have to imply the start of time?
The cause of the big bang I would think was purely random.
Causality must have time and since time was not the same in the prelude of the big bang then purpose would have no effect on the occurrence or a 'beginning', that is if you consider the big bang the very beginning.
Therefore something must exist during the prelude that is acausal. Something acausal would imply that there is no cause to govern the future of it from the past or present instances. The only way I can see this being possible is for every part of this 'something' to be the same so as to have every instance of its existence infer the outcome of its existence in another instance.
Matter is governed by the fundamental forces of nature therefore is it very causal, so rule matter out as beign that 'something'.
Energy acts through entropy but only in a closed system would disorder increase, and I hope you will all consider the inpossibility of the cosmos being finite. So perhaps there is an energy that is alike all the time to create the universe as it is today. ( Any ideas would help as to what this 'something' could be

).
So I don't see why we need the creator to be 'God', although it would be interesting to study humanity's historical perception of God and sees if it parallels the 'something' I'm trying to think of.
Either the big bang is part of an infinite cycle or the big bang is not the true beginning. An instance that has logical conceivance implies a before and after of that instance. It is a paradox really, because can there be a true beginning? I mean there will always be a way to conceive the potential circumstances of an "outside of the box" realm, which will again be a box to have an outer part. Think about Olber's bubble as an example. The cosmos must surely be infinite, because in an infinite realm the outcome of 'logic perceiving life' becomes a reality.
Also, somebody mentioned how is the big bang explosion able to create a force equal in all directions? I would assume that calling the Big Bang an explosion is wrong, it is just an expansion, the balloon analogy works well in this case I think.