In a late treatise, That the Capacities of the Soul Follow the Mixtures of the Body, Galen of Pergamum infamously offered the view that the substance of the soul is identical with a bodily mixture. This thesis has been found radical and extreme in modern scholarship and is generally considered to be at odds with Galen’s ‘agnosticism’ on the substance of soul. In this paper I propose a close reading of QAM that allows us to make sense of it in (...) terms of Galen’s other work, including his late work On My Own Opinions. (shrink)