William Craig needs no presentation since Richard Dawkins refused to debate him.
Dr. Craig is considered by many a respectable philosopher and a great debater. However, the criticism he himself made about his antagonists on the internet deserves some reflection.
For doing so, I have transcribed below the essential part of his arguments against his critics - in this particular case - which may be found here on youtube.
"A key premise in the Cosmological argument is whatever begins to exist has a cause. One of the responses that it is out there in Youtube and other places in the internet, that some people just find devastating, it is so convincing... They say: Nothing ever begins to exist because everything has material out of which it is constituted and those atoms and particles existed before the thing did, so nothing ever begins to exist, the first premise is false.
And I think: what is the matter with these people? Have I always existed? Didn't I begin to exist? ... Where was I during the Jurassic Age? Was I around? It's absurd to think that I never begin to exist even though the material stuff out of which I'm made existed before me. So I don't know what is the matter with these people. They think that the Earth didn't begin to exist. That our galaxy didn't begin to exist. That once upon a time in the history of the universe there were people and dinosaurs about. It's just irrational. And yet, people think that that refutes the premise that whatever begins to exist has a cause when it doesn't do so at all. People lack rigorous thinking." (adapted)
Craig seems very confident that he is right while his opponents are just sophomoric people who have not been exposed to rigorous thinking, which, to be fair with him, is the case of the overwhelming majority of internet users.
There is not much sense in presenting here the traditional objections to the Cosmological Argument (you can find in Wikipedia) because it is not the point of this post. My primary intention is to imagine how the debate Craig deemed finished might continue.
First, I have doubts if the way the argument was put is not self-defeating for his religious purposes. If whatever begins to exist has a cause this means that everything (which exists) is caused by something else and that would include our consciousness. Therefore, our decisions, for example, between good and evil have a preceding cause and not an existence of its own. That means we are trapped in the same materialistic paradox due to the absolute absence of free will.
Maybe a more rigorous and acceptable version would be "everything but god and our consciousness…". But that was not exactly what he said.
Second Why assuming that this "law" of cause and effect has always been and will always be?
Third if his adversaries would appeal to the (dubious) concept of "eternal" that religious people invariably do and apply it over matter and energy, then their answer is sound! In fact, all the argumentation boils down to that. Matter and energy are eternal and identity is just the successive and endless transformations that they (matter and energy) suffer.
Besides Craig unnecessarily extended his criticism to things that his adversaries clearly did not mean to imply.
He was not able to use an emotively neutral language thus making it more difficult for the exchange of ideas to continue, distracting for a while the discussion from the main issue.