The vast majority of practicing scientists (except for a few propagandists like Pinker) probably do not embrace scientism, but it is the idiom journalists use to popularize scientific findings for a nonscientific audience. It is not, to be sure, an outlook based on the scientific method—the patient weighing of experimental results, the reframing of questions in response to contrary evidence, the willingness to live with epistemological uncertainty. Quite the contrary: scientism is a revival of the nineteenth-century positivist faith that a reified “science” has discovered (or is about to discover) all the important truths about human life. Precise measurement and rigorous calculation, in this view, are the basis for finally settling enduring metaphysical and moral controversies—explaining consciousness and choice, replacing ambiguity with certainty. The most problematic applications of scientism have usually arisen in the behavioral sciences, where the varieties and perversities of experience have often been reduced to quantitative data that are alleged to reveal an enduring “human nature.”
The scientism on display in the happiness manuals offers a strikingly vacuous worldview, one devoid of history, culture or political economy. Its chief method is self-reported survey research; its twin conceptual pillars are pop evolutionary psychology, based on just-so stories about what human life was like on the African savannah 100,000 years ago, and pop neuroscience, based on sweeping, unsubstantiated claims about brain function gleaned from fragments of contemporary research."