Among the most renowned spokesmen for the new wave of atheism is British biologist, Richard Dawkins. His bestselling book, The God Delusion, is his own personal attempt to justify atheism. There are many points with which I disagree with Dawkins, but in this post, I will restrict my comments to his objections to the vertical cosmological argument.
Dawkins writes, "[Vertical cosmological arguments] make the entirely unwarranted assumption that God himself is immune to the regress. Even if we allow the dubious luxury of arbitrarily conjuring a terminator to an infinite regress and giving it a name, simply because we need one, there is absolutely no reason to endow that terminator with any of the properties normally ascribed to God . . ." 
In this passage, Dawkins makes three unsupported assumptions that underlie his criticisms. First, he suggests that it is unreasonable to suppose the God would not be caused, even though everything else is. This is where we hear the familiar rhetorical question, "If everything has a cause, then what caused God?" However, even a cursory glance at the various cosmological arguments will show that this objection is without merit. Take the first premise of the argument from dependency:
1. Every dependent thing has a cause.
Notice that the premise is not, "Everything has a cause," where we make God a special exception. Rather, the premise states that, "Every dependent thing has a cause." If there is a first cause, then, it would have to be self-existent, and not dependent. Hence, it would not require a cause, since its existence is based solely on the necessity of its own nature.
Secondly, Dawkins considers the conclusion that there exists a first cause, rather than an infinite regress, "arbitrary." Yet, he provides no consideration of the arguments against an ontological infinite regress. In my earlier post, I provided two arguments against such a series of causes: 1) It would require an infinite series to cause something within a finite period of time; but, it would take infinite time for an infinite series to cause anything. 2) If one removes the first cause of an ontological series, then one also removes the secondary causes, as in the case of a house that collapses if it has no foundation. In fact, these are the same arguments offered by St. Thomas Aquinas, whom Dawkins says he is responding to. If this is the case, then why not deal with the arguments that Thomas offers against an infinite regress?
Thirdly, Dawkins contends that if there is a first cause, then it doesn't have to possess the attributes traditionally associated with God (i.e. omnipotence). This might seem a reasonable objection, but it glosses over the fact that after Thomas demonstrates the existence of a first cause, he immediately sets out to demonstrate analytically what the first cause must be like. It is not unreasonable to suppose that since effects in some way resemble their causes, that every dependent thing that exists (and this includes those things with power, knowledge, etc.) resembles a powerful and knowledgeable first cause. In fact, no predication is instantiated apart from the first cause, ultimately-speaking. So, why is it unreasonable to consider the first cause "God"?
Shortly later in the same chapter, Dawkins continues, "To return to the infinite regress and the futility of invoking God to terminate it, it is more parsimonious to conjure up, say, a 'big bang singularity' . . ." 
I've cut the quotation here short because the mention of a big band singularity immediately presupposes that Thomas is objecting to a temporal infinite regress, when in fact, he is only arguing against an ontological infinite regress. In this instance, we find that Dawkins is treating all cosmological arguments as if they are the same; but, that's not the case at all.
To be fair, however, Dawkins does refer to what he calls the "Crumboblious Cutlets type of regress." It is here that he muses that the atom is a "natural terminator" for a regress. Yet, even he implies that atoms are not first, given that they are composed of electrons, protons, and neutrons.  These, too, are divisible (into quarks, strings, and whatever else scientists hypothesize). However, none of these suffices as a first cause, unless one of them is simple (rather than composed of parts and divisible). Yet, something simple cannot be a body, given that bodies are divisible. Hence, the physical first cause that Dawkins suggests as an alternative to God is impossible.
I should note before concluding that I have profound respect for Richard Dawkins as a scientist. He is certainly a man of intelligence, and one of the brightest thinkers in his field of study. However, his philosophical arguments have been found wanting, as is demonstrated by many philosophers, such as Alvin Plantinga - here
 Richard Dawkins, The God Delusion, Mariner Books, 2008, p. 101.
 ibid., p. 101.
 ibid., p. 102.