It can be argued that there was no intellectual figure at work in Rome in the period of the late Republic who had more originality and influence than the Bithynian doctor Asclepiades, who founded an important medical school and was still being attacked nearly three hundred years after his death by Galen, and two hundred years later still by Caelius Aurelianus. His claims to originality rested both on his theory of the causes of disease, and on his methods of treatment. Turning away from the Empiricism recently fashionable, he argued that experience without λόγoς, theory or reason, was useless. His own theory was based on the scientific ideas of the late fourth-century philosopher Heraclides Ponticus, and seems to have postulated not ἂτoμα, tiny indivisible particles, but ὂγκoι, masses, which are continually in motion and splitting into innumerable fragments, θραύσματα, of different shapes and sizes, which re-form to create perceptible bodies. The particles were separated by invisible gaps, πόρoι or pores; friction between particles created the heat of the human body, but jamming of its pores was often the cause of pain and disease. This purely mechanistic doctrine was anathema to Galen because of its insufficient reverence for the doctrines of Hippocrates, and above all for the belief in the sympathy of the various parts of the body, the purposive character of Nature's creation, and her own healing effort; and also for the doctrine of the four, or more, humours.