INTRODUCTION

Galen's concern with methodology - i.e. the theoretical reflection upon scientific and/or philosophical method - leaps from almost every page of his extant work. Time and again he stresses the need to proceed in methodical fashion, attributing the mistakes of others to their lack of training in what he calls the rational or demonstrative method. Demonstration (or proof, apodeixis) is his key term: the ideal physician will accept nothing on authority but waits for the proof or finds it himself if needed. If you expect others to accept your assertions without proof, you behave like a tyrant ordering people about.

Galen devoted several separate treatises to the subject of method. At an early stage in his career (around 160 CE) he composed his methodological chef d'oeuvre On demonstration (hereafter, Dem.) in no less than fifteen books. Regrettably, it has not been preserved, although we can form an overall picture of its contents from references scattered throughout the extant corpus. Of particular relevance are his great works On the Doctrines of Hippocrates and Plato (PHP) and On the Therapeutic Method (MM). PHP books I-VI (composed during Galen's first stay in Rome, 162-6 CE) can be read as an extended demonstration of scientific procedure as applied to issues concerning the soul. Book IX (written after 176) includes a discussion of method, most notably division (diaeresis). MM (in fourteen books), as its title indicates, discusses the method to be used in clinical medicine. Its first two books (written around 175) are more theoretical than the others and based on the methodology advocated in Dem. as well.