For E O Wilson, to understand the operation of the human mind, and society, "The only way forward is to study human nature as part of the natural sciences."1 Wilson is unabashed in his recognition that this is a scientistic view. "It is all too easy to be seduced by the opposing view: that science is competent to generate only a few classes of information...", which he says is "obscurantism". So the basis must be: "human social behavior rests on a genetic foundation". It is "derived in a straight line from neo-Darwinian evolutionary theory that the traits of human nature were adaptive during the time that the human species evolved".
Stern criticism met Wilson's opinions, and much of it came from his own biological colleagues. They said the biological evidence adduced had "little relevance to human behavior, and the supposedly objective, scientific approach in reality conceals political assumptions." They also took exception to his rhetorical maneuvers, citing arbitrary "explanation" of traits as adaptive or maladaptive with no basis for the distinction, unjustified leaps from what might be to what is, metaphors for animal behavior that spuriously imply human behavior has the same basis, and reliance on purely speculative human prehistory.2
Wilson portrays sociobiology as the first step to scientize all knowledge. "By a judicious extension of the methods and ideas of neurobiology, ethology, and sociobiology a proper foundation can be laid for the social sciences, and the discontinuity still separating the natural sciences on the one side and the social sciences and humanities on the other might be erased." His prescription for deriving ethics is to appeal to an unexplained "nobility". The religious impulse is to be harnessed through "the evolutionary epic ... probably the best myth we will ever have." And who knows "the forms that ritual will take as scientific materialism appropriates the mythopoeic energies to its own ends." This scientific materialism is an all-encompassing world-view that serves explicitly, for those who follow the scientistic path, the purpose of religion.
As an illustration of the mythopoeic application of the evolutionary epic, one might consider the almost mystical adherence in modern academic morality to a presumed-self-justifying `diversity'. It is as if diversity of all types were justified because the evolutionary value of human biological diversity calls for humans to cherish and promote both the diverse genes and their metaphorical and cultural reflection. This purported implication is far more humane and appealing than the practically opposite implication drawn by the eugenicists; but its logic is no more convincing. It seems significant that evolutionary metaphysicians of adjacent generations have drawn practically opposite conclusions about ethics and social policy, from essentially the same scientific theory.
Evolutionary psychology has similar objectives and rhetoric to Sociobiology. Its grand claim is "to keep beliefs and desires in our explanations of behavior while planting them squarely in the physical universe."3 But its program also appears aimed to give a naturalistic account of ethics to the exclusion of theology. In this, it encounters a major difficulty. The physical world is said to work without "backward causation", teleology, purpose, or intentionality, and its absence is the main-stay of the atheist position. Yet if human intentionality (beliefs and desires) is part of nature, then purpose appears not to be excluded. This difficulty is brought on by scientism. I agree that intentional teleological explanations are not part of science's methods. My position is that intentionality is nevertheless a perfectly acceptable (indeed obvious) way to understand many phenomena, but that it is part of non-scientific knowledge and explanation. Failing to distinguish different types of explanation because of scientism is the cause of the inescapable naturalist's dilemma.
The main weakness of evolutionary psychology is that it is generally content with composing stories to explain some fact of psychology in terms of a hypothesized evolutionary history. In most cases such stories are independent of other phenomena. They have no independent supporting evidence. They are not integrated into a scientific explanatory web that would make them a robust part of theory; they are subject-specific, and regularly sound like special pleading or mere speculation. In this respect they contrast with evolutionary explanations of biology and physiology, some of which do gain strong plausibility from serving as consistent integrated explanations of multiple phenomena. Psychological explanations that would escape this just-so-story criticism might be correct predictions from evolutionary arguments. In an attempt at such a predictive confirmation Steven Pinker, for example, offers an explanation of parents' reported attitudes to "Sophie's choice" [Whether to sacrifice a child when circumstances demand it.] based on hypothesized hunter-gatherer life expectancies. The prediction and its confirmation are unconvincing. Passing over more obvious down-to-earth intentional explanations in favor of scientific-sounding evolutionary speculations is a scientistic folly. Such birth-order arguments (say Pinker's own sources) are considered by the majority in the field as a "mirage."4
Evolutionary psychology seems to draw much of its momentum from a fundamentalist scientism, which regards naturalist explanation as the only explanation worth having - even of the human mind and society. It has appeal as a way to incorporate consciousness and culture into a scientistic world-view, especially for those who want a stick with which to beat religion. But it falls far short of the convincing explanations science offers of the physical world, of nature. And it must do so, because much of psychology does not possess the characteristics that are required for scientific analysis.
For all their intellectual weakness, evolutionary psychology and sociobiology constitute the main foundation of the claim by today's militant atheists that religion as a human phenomenon is explained away by science. Biological evolution rests on an enormous range of reproducible physical, paleontological, biological, and now genomic evidence. There's a huge difference between that and the speculations of evolutionary psychology. It is understandable that theist non-scientists have difficulty distinguishing between them and react with suspicion toward all evolutionary theory. The challenge scientism presents, though, is precisely that task; to understand which aspects of the world can reliably be described by natural science, and which cannot.