Instrumentalism
Instrumentalism is the view within the philosophy of science, scientific theories are nothing more than tools. It is thus opposed to the epistemology of realism.
This position was represented by Ernst Mach (1838-1916), Henri Poincaré (1854-1912) and in particular by Pierre Duhem ( 1861-1916 ).
Instrumentalist arguments are also often encountered with representatives of neoclassical economics as well as any models in the social sciences who work with assumptions of rational action.
According to the instrumentalism the hypotheses and the theoretical laws of a theory are neither true nor false (such as alleged by realism), but to establish an empirical adequacy of the conclusions from the assumptions of a theory are for reference only. The postulates of a theory apply only to the instrumentalist as a means to an end, ie as instruments.
Pierre Duhem argued that physical theories do not explain, only represent. The target of a physical theory, it is not to explore those entities which cause the phenomena. One theory behaves according to Duhem rather as a symbol to the thing signified: theories are neither true nor false. However, theories represent the phenomena not only they also arrange in Duhem's words, theories classify empirical laws.
Karl Popper advocated a mode of explanation by means of models of situational logic and one ( by itself empirically false ) rationality hypothesis. Instrumentalism it intends to exclude, by requiring a methodological decision about which model to get the empirical truth of the next.
Hans Albert also championed the position of realism, by accusing Jürgen Habermas, assume the position of instrumentalism in knowledge and interest.