Galen believes that the Empiricist position, avoiding any statement about unseen entities and basing itself entirely on experience (empeiria, peira), will lead to the correct therapeutic result in many cases. Faced with a choice between being a pure Empiricist and adopting an erroneous theory, one should infinitely prefer the former. However, Galen’s view remains that theoretical knowledge of the internal workings of the body is possible—that is, one can deduce facts about the non-evident (adēla) on the basis of one’s observations. Further, this knowledge of the workings of the body, its phusis, gives one an understanding of pathology—in particular, a differentiated pathology based on a knowledge of the different internal parts and the different forms diseases may take in them, despite superficially similar symptoms—which will in some cases enable one to make the right diagnosis, and therefore prescribe the correct treatment, where the Empiricist would not.