EXPLANATION OF CONCEPTS

Realism and instrumentalism provide two alternative interpretations of science and of factual knowledge in general. According to realism such knowledge is descriptive of (general or particular) features of the universe. According to instrumentalism even a theory that is wholly correct does not describe anything but serves as an instrument for the prediction of the facts that constitute its empirical content. Thus, considering Newton's theory of gravitation, a realist would remark that it teaches us of the existence, in addition to physical objects and their spatiotemporal behaviour, of entities of an altogether different kind which cannot be directly seen, heard, or felt, but whose influence is still noticeable enough, viz. forces. An instrumentalist, on the other hand, will take the position that there are no such entities and that the function of words like ‘gravitation’, ‘force’ and ‘gravitational field’ is exhausted by their giving an abbreviated description of the spatiotemporal behaviour of physical objects. He may even deny the existence of these objects and regard object words, too, as instruments, usable for the ordering and predicting of sense data. In this paper I shall argue that realism is preferable to instrumentalism.

THE DISTINCTION IS NOT PURELY VERBAL

Such an argument is of interest only if the issue between realism and instrumentalism is more than just a quarrel about words. Some philosophers deny that it is: Nagel, for example, holds that ‘the opposition between these issues is a conflict over preferred modes of speech’ which cannot be resolved in an objective manner.