Hawkings has conceded that time has begun to exist, no doubt.
There are 3 possibilities if the universe has a beginning in time.
Either time begins with the universe, time began for a finite time
before the universe, or time existed for an infinite period before
the universe. Kalam rejects the last 2 possiblities so we'll just
go with the first one. If the act of God creating the universe
coincided with time in the beginning of the universe, then that act
must have began to exist. This means the act must have had a cause
(God). The cause (God) must have also began to exist, and so an
infinite regress threatens.
Suppose, then, that God starts time before the universe.
Perhaps he has a countdown: "5, 4, 3, 2, 1... kaboom!" In this
case, the beginning of time would be an event in the mind of God -
the start of the countdown. But here again, if God's act of
starting the countdown is the beginning of time, that act begins to
exist, and the temporal cosmological argument requires that that
act also have a cause. Once again the infinite regress abyss yawns.
Furthermore, as the British philosopher Le Poidevin pointed out,
the 3rd premise of Kalam will be false if time was eternal or if
time existed as a close loop with each moment preceding and
following each moment.
Kalam claims that the cause of the universe is outside "the
universe" Hence, it is of upmost importance that we verify how
causality works outside of the universe. How then, can it be said
that the universe MUST be caused if one does not know if causality
even exists outside of the universe! The assumption of Kalam is
that since what we observe in this universe follows the line of
cause and effect, therefore the universe must also follow the
principle of cause and effect. Which is like I pointed out, a
fallacy of composition.
Occams Razor is a very interesting concept. I'm glad you brought
that up. You see, Occams Razor does nothing to demonstrate what is
true, it only demonstrates what is simple. Furthermore, if Occams
Razor were to be employed, would the American physicist Lawrence
Krauss be correct in asserting that the universe began out of
virutal particles (a view quite a number of physicists hold - Alan
Guth, Michio Kaku, Carl Sagan, Neil Tyson). Blue is immaterial,
blue is a concept. Blue is simply something affected by photon
diffraction on a line spectrum. Photons themselves have no rest
mass; so cannot be considered material.
If you ask me, I think it is pointless to argue what was prior
to "In the beginning God...". It's just academic. But we all
agree that there was a beginning. The clock started ticking. If it
started then something must have caused it to start. Now, we
already said that whatever created the universe must be timeless,
so why do you now suggest that it is not and thus requires a cause?
We can either go infinite regress which explains nothing or we
start with a necessary being God. There is nothing illogical about
an uncaused cause.
Let's again not confuse the proof with the logic of the
argument. Like it or not, there is no way we can transcend our
confines to observe anything outside the universe. This is our
limitation. But this does not in anyway proves that there is no
cause that is outside of the universe. Cause and effect is a
universal law, so it is perfectly logical and reasonable to apply
it to the universe. Remember, your issue is more of how to verify
the cause, not that there is no cause. Agnosticism about the cause
is not the same as denial of the cause.
Occam's Razor is a method of reasoning, not a proof of anything.
It is invoked to remove UNNECESSARY entities to explain something.
The simpler the explanation it should be PREFERRED over those that
multipliy entities unneccessarily. There is no need to burden
ourselves with extra entities when a simpler one is available.