Above all, do not attempt to use science (I mean, the real sciences) as a defence against Christianity. They will positively encourage him to think about realities he can’t touch and see. There have been sad cases among the modern physicists. If he must dabble in science, keep him on economics and sociology; don’t let him get away from that invaluable “real life.” But the best of all is to let him read no science but to give him a grand general idea that he knows it all and that everything he happens to have picked up in casual talk and reading is “the results of modern investigation.” Do remember you are there to fuddle him. From the way some of you young fiends talk, anyone would suppose it was our job to teach!
CS Lewis, The Screwtape Letters
Austin L. Hughes at The New Atlantis has a first rate look at science and scientism:
An additional strength of the falsifiability criterion is that it makes possible a clear distinction between science properly speaking and the opinions of scientists on nonscientific subjects. We have seen in recent years a growing tendency to treat as “scientific” anything that scientists say or believe. The debates over stem cell research, for example, have often been described, both within the scientific community and in the mass media, as clashes between science and religion. It is true that many, but by no means all, of the most vocal defenders of embryonic stem cell research were scientists, and that many, but by no means all, of its most vocal opponents were religious. But in fact, there was little science being disputed: the central controversy was between two opposing views on a particular ethical dilemma, neither of which was inherently more scientific than the other. If we confine our definition of the scientific to the falsifiable, we clearly will not conclude that a particular ethical view is dictated by science just because it is the view of a substantial number of scientists. The same logic applies to the judgments of scientists on political, aesthetic, or other nonscientific issues. If a poll shows that a large majority of scientists prefers neutral colors in bathrooms, for example, it does not follow that this preference is “scientific.”
Popper’s falsifiability criterion and similar essentialist definitions of science highlight the distinct but vital roles of both science and philosophy. The definitions show the necessary role of philosophy in undergirding and justifying science — protecting it from its potential for excess and self-devolution by, among other things, proposing clear distinctions between legitimate scientific theories and pseudoscientific theories that masquerade as science.
By contrast to Popper, many thinkers have advanced understandings of philosophy and science that blur such distinctions, resulting in an inflated role for science and an ancillary one for philosophy. In part, philosophers have no one but themselves to blame for the low state to which their discipline has fallen — thanks especially to the logical positivist and analytic strain that has been dominant for about a century in the English-speaking world.