For some years Barry has been pushing here the so-called Cosmological Argument for the existence of God. It is an argument I have been exposed to in its many forms -- going back to Plato and beyond -- since my high school religion classes and my college apologetics and philosophy classes. Not to mention a lifetime of reading. So, for what it's worth, and without inviting debate, here are the reasons why I think the argument is a nonstarter. I suspect that most contemporary scientists who do not have a prior commitment to theism will agree with me.
In its most common expression the argument is this: Every event has a cause. Trace a sequence of events backwards in time and one must eventually arrive at an uncaused causal agency. That agency is God.
The uncaused cause (or prime mover, or whatever) is immune from requiring a cause because it is eternal. But of course the universe itself may be eternal, as Plato and Aristotle assumed. Turtles all the way down.
Present cosmology suggests that the universe had a beginning, the Big Bang. It is foolhardy to base philosophical/theological arguments on contemporary scientific theories; theories are subject to amendment, even to radical change. The Big Bang, for example, may turn out to be merely a Big Bounce in an eternally oscillating universe, or this universe may be just one of many in an eternally bubbling metaverse. Who knows? But let's assume the Big Bang is a true beginning. Does it require an uncaused cause; i.e. God. Space and time and therefore causality came into existence with the Big Bang. Why that, why then? The only honest answer is "I don't know." Call the "I don't know" God if you wish; you have added zero information to the sum of human knowledge.
In any case, the Cosmological Argument does not require the uncaused cause to have any of the properties that theists commonly insist on -- personhood, love, justice, or the capacity to act within creation to work miracles or answer prayers.
We used to wonder whether or not the universe was finite or infinite in spatial extent. It is hard to imagine space going on forever, and impossible to imagine space coming to an end. Now, with the mathematics of general relativity, we can imagine unbounded finite space. Who knows what future developments in science or mathematics will throw light on the question of beginnings.
Do we know why there is something rather than nothing? Or why the laws of nature are what they are? Of course not. The theist gives it a name -- God -- and assumes the problem is solved. The scientist keeps probing.