In the last couple of days, two Christian apologists have published critiques of the Kalam cosmological argument.
Calum Miller provides an extremely thorough, open-minded critique.
Over at Answers in Genesis, Danny Faulkner has written an interesting article entitled, “Universe by Design: Misconceptions about General Relativity, Cosmology, and the Big Bang.” Among others, the article has a section entitled, “The Big Bang Does Not Prove God’s Existence.” Faulkner provides the same objection made by Quentin Smith and others, namely, that if time began with the big bang, then an appeal to causality will not demonstrate the existence of God.
Both of these critiques were written by Christian apologists. The fact that they are apologists shows what should already be obvious: one doesn’t have to be an atheist, much less an ‘unreasonable’ atheist, in order to find the kalam cosmological argument wanting. This point shouldn’t need to be said, but other Christian apologists, such as William Lane Craig, sometimes give the opposite impression.