A stronger case for a mind–body identity theory in Galen, however, is provided by the discussion of the relationship between rational soul and physical features of the brain, especially in QAM. The central aim of that work is to demonstrate the extent of the influence of the body, specifically bodily mixture, on the soul; this Galen does with examples from medicine (e.g., mental derangements with physical causes) as well as everyday experience (drunkenness, effects of physical environment). How, he asks, could a soul which is not corporeal be be affected by such physical factors, and indeed be caused to leave the body as a result of certain physical conditions (QAM 3, 381)? In a number of passages, he suggests not just the dependence of the soul on bodily mixture, but the identity of the two: