Scientism, like any ism, is an ideology, and, like any ideology, is driven as much by ambition, wishful thinking, and base emotion as it is by rational analysis. Science is not the fount of human perfection and happiness; it is a product of humankind’s ability to reason and to apply reason in human affairs. The beneficial application of science requires moral guidance and ethical scrutiny, because blind pursuit of scientific knowledge leads to uncomfortable spaces.
The Nazis dunked soviet POWs in frigid water in a “scientific” attempt to devise strategies to help downed Luftwaffe pilots survive in the North Sea. One conclusion of such experiments was that exposure to cold caused cerebral hemorrhages. This “scientific” discovery turned out to be wrong. The United States government scientifically investigated the course of untreated syphilis in African-Americans; very scientific, yet somehow unpraiseworthy. The Imperial Japanese Unit 731 did competent scientific work, so much so that their biological warfare experiments were able to decimate several Chinese villages. (The scientifically oriented American government, rather than opting for war crimes complaints gave many of the perpetrators immunity, because, hey, SCIENCE!). The soviets' use of psychiatry on political dissidents is probably not an example of “improved policies and regulations that serve our best interests.” Orbiting the white nationalist fringe is the “human biodiversity” movement that uses scientific evidence to argue that certain racial and ethnic groups have intelligence, behavioral and personality traits that are heritable and therefore partially genetically determined, a scientific hypothesis that would likely be rejected by scientism on grounds unrelated to method.
One concern that naturally arises is that of avoiding "abuses" of science. Science has no reliable way of identifying “abuses” apart from human values. Science has no inherent conscience.
The modern scientist has much in common with the prehistoric thinker who thought that virgin sacrifice kept volcanoes from erupting or that fickle gods made the sun rise and rains come., Both applied the evidence at hand to questions relevant to their interests and reached conclusions constrained by the state of their knowledge. Much of what modern science knows is wrong; there is even a book, “Ending Medical Reversals” that focuses on the harm done by adopting therapies and theories as scientific based more on apophenia and wishful thinking than on rational rigor This is why “consensus” is irrelevant to the advance of scientific knowledge, and is no substitute for it. Remember saccharin and how it causes cancer? Or how drotrecogin was the holy grail of sepsis treatment? What was the state of consensus regarding phlogiston theory 400 years ago? What does one one say about the scientific certainty regarding “gender fluidity?”
Science, is a tool without an inherent moral or ethical constraint. The scientific method is useful, for both good and ill, but is not infallible. Its usefulness derives from the ability of human reason to make sense of objective evidence, and that is all it is. It is not something to be venerated or blindly believed. It is something that can be cynically exploited by charlatans. It may be used as a prop to argue for greater government control over people’s lives just as hucksters with knowledge of solar eclipses were able to con those innocent of astronomic knowledge by implying some mysterious power. Science does not validate atrocity or immorality (as the Tuskegee syphilis and Unit 731 experiments show) merely by their being scientific, and science does not validate any ideology or political fashion that presumes otherwise. The use of science for political ends does not have a happy history.