"belief in the omnipotence of scientific knowledge and methods and in their applicability to everything," a derogatory term, by 1870 (G.B. Shaw); see science + -ism. An earlier word was scientificism (1825) "restriction of analysis or explanation to what is scientifically demonstrable."
Particularly is the present age of science characterized by a predominance of observation over reflection. One would think from the general tendency in this direction that science was little else than gathering of facts. So it has come to pass that a fresh discovery gives warrant for any inference,—for any theory. ... That facts should be valued mainly for the principles they reveal, modern scientism could hardly understand, much less believe. [Henry N. Day, "President McCosh's Logic," The New Englander, July, 1870]