But actually, the argument (even if we accepted it fully) doesn't argue for a first cause, just a cause for the universe. There is nothing there that prevents an infinite regress beyond that cause (special pleading aside).
Then what's the justification for either premiss?
I like all the thinking on this thread.
And I have been reading for years on what scientists conclude on the beginning of the Universe.
And what religious dogma says about it.
And yes, taking the "God did it" explanation out of the equation, this is how it is described.
Everything began with a singularity, that due to a very small fluctuation in its existance, resulted into a Big bang.
From a nice summary on Wikipaedia:
Singularity (system theory), in dynamical and social systems, a context in which a small change can cause a large effect
Gravitational singularity, in general relativity, a point in which gravity is so intense that spacetime itself becomes ill defined
Initial singularity, a hypothesized singularity of infinite density before quantum fluctuations caused the Big Bang and subsequent inflation that created the Universe
Penrose–Hawking singularity theorems, in general relativity theory, theorems about how gravitation produces singularities such as in black holes
...
Anyhow, science is in general terms in agreement that the Universe, planets, stars and everything inbetween is the result of huge ammounts of energy contained in a infinitely small space area, errupted to create the very particles atoms are made off.
This created different metals, after huge stars exploded to produce heavier elements, particles, solarsystems, and eventually life.
...and so on.
Now, we can postulate and debate about how this came about, and learn from Stephen Hawking's Great design" that Gravitational fields created this singularity of ennergy, and a Creator is not needed for Creation.
We can name it, and give it descriptive mumble jumble such as the "First cause" and philosiphy about where this Cause came from, and on what this Cause had an effect on to get the Universe4 going, but we will not be able to get an answer on what the first cause is. Neither will we be able to determine if the first cause working on some singularity that actually consisted of some form of Energy, and how this changed into solid matter.
We know how to change Matter into Energy, but to change Energy into matter is something I assume, to be impossible.
Now lets look at the possible Cause of everything.
If Hawking said it was "Gravitational fields", we can again use our mumbo jumbo "What was the cause of Gravity?
And Hawkin could not explain that.
What scientists are doing to explain away any idea of a Creator, is to ask, "If there are a Creator, what was his first cause".
Therefore, the religious person and the Atheistic person are in a duel fight asking each other..
What caused your first cause.
From my viewpoint, I "believe" in the Creator of the Universe, rather than a "component" of the Universe (gravity).
The reason be that I will rather worship a Creator who described how He made everything, than in say, the Sun, Moon, Stars, any Greek or Egyptian god, for they are all created entities.
I will never give credit for the creation to something such as "Gravity", for such a recognition is blatant Idolatory.
Even when I were still of mind that there are no god, I still did not like to consciensely name a BB, or Gravity the cause of everything.