 1242, when Ibn al-Nafis published his book "Sharh tashrih al-qanun li’ Ibn Sina" ("Commentary on Anatomy in Avicenna's Canon"), in which he reported his discovery of the pulmonary circulation.Galen saw himself as both a physician and a philosopher, as he wrote in his treatise titled "That the Best Physician Is Also a Philosopher".Galen was very interested in the debate between the rationalist and empiricist medical sects, and his use of direct observation, dissection and vivisection represents a complex middle ground between the extremes of those two viewpoints.