Instrumental Unification: Optical Apparatus in the Unification of Dispersion and Selective Absorption

Abstract

Unification has long been regarded by many, both philosophers and scientists, as a highly respectable goal of scientific research. According to a widely received account, which was proposed first by William Whewell in the 19th century, unification can establish the truth. Whewell (1847, vol.2, p.285) believed that „when the explanation of two kinds of phenomena, distant, and not apparently connected, leads us to the same cause, such a coincidence does give a reality to the cause, . . . This coincidence of propositions inferred from separate classes of facts, is . . . one of the most decisive characteristics of a true theory . . . ‟. The assumption behind Whewell‟s admiration of unification is that a unifying theory possesses a higher degree of confirmation because of the increase in both explanatory and predictive power. Many contemporary philosophers of science, like Friedman and Glymour, also adopt this assumption and believe that unifying theories are more likely to be true (Friedman 1983, pp.241-245; Glymour 1980, pp.31-50). Following this line of reasoning, many philosophers of science define unification as a logical process that takes the form of explanation or prediction. Unification is achieved when a theory can explain two or more classes of known facts, when it can predict cases that are different from those the theory was designed to explain, or when it can predict unexpected facts. Some recent works in both history and philosophy of science raise doubts about the Whewellian assumption that equates unification to truth discovery. In her fine analysis of the unification achieved by Maxwell‟s electromagnetic theory,