To a large extent Collins relies on arguments from the works of C.S. Lewis for his justification that God must exist. He is particularly smitten by the idea of a universal Moral Law which, like Lewis, appears to him as being something that could only be divinely authored. It is obvious, Collins asserts, that something like the awareness of right and wrong has to have come from some higher power, else why would it exist across all cultures and be unique to the human species?
In fact, Collins asserts, beside this moralistic awareness, it is such things as “the development of language, awareness of self, and the ability to imagine the future” that are part of the enumeration of the specific characteristics of modern humans. The fact that language, for example, is the product of a reasoning mind that, over time, develops as a result of genetically derived mental improvements makes it difficult for the reader to accept the author’s declarations. If language is a uniquely human quality, and it has come about from genetically driven evolution, why no reasoning that provides the justification for the development of ethical behavior? To Collins, the very awareness of what is right and wrong can only be from some divine power, but his reasoning does not support it. Although elsewhere in the book he is highly critical of the “god of the gaps” argument employed by Intelligent Design creationists, who chase down the gaps in scientific knowledge to proclaim that this is where God intervenes, Collins’ deduction that evolution cannot account for the Moral Law is just another gap. He reviews some of the modern evolutionary explanations for the evolution of the moral sentiments, but he dismisses them as inadequate, and then draws his conclusion. This is the fallacy of personal incredulity — “I can’t think of how X can be explained naturally, ergo X must have a supernatural explanation.”
The basic idea behind Eberle's critique of Collins is this: Since Collins can see how evolution can provide an explantion for language and mind, he ought to be able to see how evolution can provide and explanation for morality, too. He ought, that is, to avoid the god-of-the-gaps with regard to morality just like he avoids hte god-of-the-gaps with regard to language and mind. Unfortunately, Eberle's critique of Collins is doubly defective.
First, Eberle and Collins both think that science in general and evolution in particular can and do provide an adequate explanation for the origin of human consciousness and it's capacities for language, reasoning, etc. But, it does nothing of the sort. There is no scientific theory on the table anywhere in the world that even comes close to providing a naturalistic account of the mind--and this is something that even atheist philosophers and neuro-scientists are aware of. No evolutionary "just-so" story cuts mustard here. Even Michael Shermer, editor of Skeptic and eskeptic admitted this fact in a recent debate with Doug Geivett at the Universtity of Alabama at Birmingham. Of course, this doesn't necessarily mean that a naturalistic account of mind is impossible, but the point is that Eberle and Collins ought to know better than to write and talk as if such an account is "in the bag". Not only is it not in the bag, nobody has the remotest clue as to how a naturalistic account of the mind might go. This is why it is disingenuous at best to accuse the intelligent design guys of the god-of-the-gaps.
Second, even if there were a naturalistic account of the mind and language, this would have no bearing on the question of morality. This is where I think Collins has got it right and Eberle has missed the boat. Eberle thinks that defenders of the moral argument simply commit his so-called fallacy of personal incredulity--we can't (yet) explain morality naturally, therefore, it must have a supernatural origin. Perhaps Collins' version of the moral argument for God commits this fallacy, but most philosophers who defend the argument do not. The problem for a naturalistic account of morality is not simply that it seems hard to explain it natually. Rather, it's that the existence of an objective morality seems postively inconsistent with naturalistic principles (as even failed naturalistic ethical theories seem to show). In fact, Eberle himself proves the point when he goes on to say. . .
Collins then compounds the problem with his arguments by asserting, without foundation, that altruism is unquestionably good, and that it can only be explained by the existence of the Moral Law. The fact that the goodness of altruism is a subjective judgment and open to considerable debate is ignored. Furthermore, he never addresses the studies that have shown that altruism is not unique to the human species, and he never explains why the altruistic behavior of a member of the group could not be something that evolved, initially, simply as a necessity for the survival of the group.
What Eberle says here is that Collins fails to realize that morality may not be objective. That is, moral properties and values may simply be subjective beliefs that we have adopted as a species in order to better survive--but, there is nothing objectively true or binding about morality. Here Eberle is echoing the sentiments of other evolutionary naturalists like Dawkins and Ruse who claim that morality is simply a social convention coughed up by evolution, but as such is jsut an illusion--there's nothing objectively good about altruism and nothing objectively bad about rape and murder. But, this is precisely why Eberle's critique of Collins' moral argument fails. Collins is trying to explain why a objective moral law exists. And naturalism just won't do as an explanatory hypothesis. Sure, if morality is a subjective illusion and there really isn't such a thing as right and wrong, then evolutionary naturalism provides a perfectly good expalanation for why we all mistakenly think that right and wrong exist. But, if an objective moral law really does exist, then naturalism is almost certainly false. And it would seem that even Eberle would have to agree in that case that no fallacy of personal incredulity has been committed.