Galen on the chances of life

On the subject of nature, Galen was an indomitable optimist.He embraced the claim made in Plato's cosmological magnum opus, the Timaeus, that the world and everything in it were created by an intelligent Demiurge, and he never grew tired of admiring the creator's handiwork. He accepts, with equal enthusiasm, Aristotelian teleology, according to which each part of an organism is oriented toward an end (telos) – namely, the life proper to that organism. For Galen, every part of the human body has been created “so that it would not have been better had it come into being differently”. His monumental hymn to Nature, On the Usefulness of Parts, is nothing less than an attempt to prove this claim. Throughout his vast corpus of writings Galen is passionately committed to the intelligence of Nature and the boundless foresight with which “she” enables us to live and thrive. Yet, at the same time, Galen did not believe that the Demiurge had created a perfect world. In a well-known critique of the God of Moses, one that echoes the Timaeus, he emphasizes that the Demiurge achieves the best results he can, given the material conditions under which he has to work. These conditions mean, among other things, that the organism’s continued survival is never guaranteed in advance. It is always, rather, only a likely outcome, and therefore firmly grounded in the domain of probabilities. As it turns out, there are many ways in which things can go wrong. To the extent that Galen was, first and foremost, a physician, he was exceptionally well acquainted with the malfunctioning of the human organism.