Philip Kitcher, prominent philosopher of science in The New Republic:
The problem with scientism—which is of course not the same thing as science—is owed to a number of sources, and they deserve critical scrutiny. The enthusiasm for natural scientific imperialism rests on five observations. First, there is the sense that the humanities and social sciences are doomed to deliver a seemingly directionless sequence of theories and explanations, with no promise of additive progress. Second, there is the contrasting record of extraordinary success in some areas of natural science. Third, there is the explicit articulation of technique and method in the natural sciences, which fosters the conviction that natural scientists are able to acquire and combine evidence in particularly rigorous ways. Fourth, there is the perception that humanists and social scientists are only able to reason cogently when they confine themselves to conclusions of limited generality: insofar as they aim at significant—general—conclusions, their methods and their evidence are unrigorous. Finally, there is the commonplace perception that the humanities and social sciences have been dominated, for long periods of their histories, by spectacularly false theories, grand doctrines that enjoy enormous popularity until fashion changes, as their glaring shortcomings are disclosed.
Human social behavior arises, in a complex social context, from the psychological dispositions of individuals. Those psychological dispositions are themselves shaped not only by underlying genotypes, but also by the social and cultural environments in which people develop. Cultural transmission occurs in many animal species, but never to the extent or to the degree to which it is found in Homo sapiens. Human culture, moreover, is not obviously reducible to a complex system of processes in which single individuals affect others. Rigorous mathematical studies of gene-cultural coevolution reveal that when natural selection combines with cultural transmission, the outcomes reached may differ from those that would have been produced by natural selection acting alone, and that the cultural processes involved can be sustained under natural selection. Whether this happens in a wide variety of areas of human culture and domains or is relatively rare is something nobody can yet determine. But culture appears to be at some level autonomous and in some sense irreducible, and this is what scientism cannot grasp.