In my last post I looked at Erik Wielenberg’s response to the objection that, in the absence of God, people lack compelling reasons to comply with morality’s demands. A second objection Wielenberg briefly addresses is that without certain theological doctrines, one cannot provide a plausible basis for human rights and dignity. Wielenberg, here again, takes Craig as paradigmatic.
If there is no God, then what’s so special about human beings? They’re just accidental by-products of nature that have evolved relatively recently on an infinitesimal speck of dust lost somewhere in a hostile and mindless universe and that are doomed to perish individually and collectively in a relatively short time
Craig’s rhetorical question alludes to a serious point, made in more detail by Peter Singer, Louis Pojman, and Nicholas Wolterstorff, this is that it is hard to plausibly accommodate the thesis that all human beings have equal dignity and rights outside a theistic framework. Wielenberg’s response is that human rights are grounded in “non-moral intrinsic properties of human beings” He notes: “Human beings can, reason, suffer, fall in love, set goals for themselves and so on. God or no God, human beings obviously differ when it comes to intrinsic properties than dogs or mere lumps of clay”
Wielenberg here appeals to certain higher cognitive capacities human beings possess that other animals lack.
This brief response to Craig is central to his Wielenberg’s rebuttal of evolutionary debunking arguments against moral realism latter in the book. Sharon Street and others have raised epistemological challenges to moral realism by noting that many of our basic evaluative capacities, our disposition to judge certain types of behaviour as morally wrong, has been shaped by naturalistic evolution. Naturalistic evolution, however, isn’t guided by considerations of truth, in selecting such dispositions, but by adaptability, these basic evaluative judgements exist, because making such judgements enabled our ancestors to reproduce effectively in the environment in which they lived. Street notes “the striking coincide between independent moral truths posited by the realist and the normative views evolution has pushed us towards” and “challenges the realist to explain this coincidence.”
Wielenberg proposes that “our cognitive capacities” explain the coincidence. Moral rights D supervene upon any creature that possesses certain cognitive capacities. Seeing these are the same cognitive capacities which produce moral beliefs. It follows that any being which believes it has moral rights will necessarily have them.
Wielenberg specifies that the supervenience relationship here involves both modal covariation, and a form of “robust causation” analogous to the way theist understand God’s relationship to the created universe, just as Theists believe that God immediately sustains the universe in existence moment by moment simply by willing its existence. So, natural those properties which constitute our higher cognitive faculties, robustly cause the existence of moral rights, without any intermediatory agency or laws of nature.
This answer both to the grounding of human rights and evolutionary debunking arguments has a cost. As Wolterstorff  and Singer . have both pointed out, while it is true that normal adult humans have the cognitive capacities in question, many important categories of human beings do not. Infants and small children cannot reason, or fall in love, set goals for themselves, nor do they have the developed moral cognition Wielenberg refers to. In fact, David Boonin has noted: “by any plausible measure dogs, and cats, cows, and pigs, chickens and ducks are more intellectually developed than a new born infant.”.
So, Wielenberg’s answer gives us no reason for thinking a child or infant has a rights or dignity, over and above any other animal. In fact, seeing moral rights modally covary with possession of the relevant cognitive faculties, such capacities are necessary and sufficient for the possession of moral rights. Consequently, His position seems to entail that infant’s small children, and mentally impaired human adults have no moral rights.
 Wielenberg, Robust Ethics 51, the citation is from William Lane Craig and Walter Sinnott-Armstrong God: A Debate Between a Christian and an Atheist (Oxford: Oxford University Press, 2004) 18
 Ibid 51
 Ibid 155
 Ibid 134-175
 Nicholas Wolterstorff Justice: Rights and Wrongs (Princeton NJ: Princeton University Press, 2008) 325-341.
 Peter Singer, Writings on an Ethical Life (London: Harper Collins Publishers, 2001) 186-187
 David Boonin, A Defense of Abortion (Cambridge: Cambridge University Press, 2003), 121, the neurological data is summarised in Michael Tooley’s Abortion and Infanticide (New York: Oxford University Press, 1983) Ch. 11.5.