Published online by Cambridge University Press: 31 July 2008
Successes in science tend to be successful attempts at reduction and causal interaction. The reduction of the interaction of bodies to the laws of motion and the reduction of chemical phenomena to elements and their interactions are good examples. In these cases reductionism leads to observed phenomena being explained by a relatively small number of basic concepts and the laws which govern the interaction of the concepts. The spectrum of inquiry that stretches from common sense to scientific psychology is infused with a tendency toward reductionism. Hippocrates and Galen originated and developed, respectively, the notion that temperamental differences might be reducible to the amounts of four bodily fluids, or humours (black bile, yellow bile, blood and phlegm), that a person produced. Astrologers reduced stable personality differences to the positions of the stars and planets at the time of birth. And differential psychologists have reduced the personality trait adjectives contained in the lexicon to about five major dimensions.