In fact, there is some complexity in Galen’s precise view of elements, and in particular as to the relationship of fire, air, earth, water (which henceforward, for convenience, I shall term “element-bodies”) with hot, cold, wet, dry (henceforward, “element-qualities”); see Hankinson 2017; Singer 2021a. Although at times he uses the term stoicheia for both element-bodies and element-qualities, in his most detailed account, in his Commentary on Hippocrates’ Nature of the Human Being (HNH) (I.3; cf. Hipp. Elem. 6, esp. 112–16), he clarifies that properly speaking the former are elements, stoicheia, in the sense that they cannot be physically separated into anything else, but that they are further conceptually divisible into different “principles” (archai): specifically, each of the element-bodies (stoicheia) must be understood as the outcome of the reception into a substrate, quality-less matter, of the extreme of a particular quality (that is, the element-qualities). Galen’s element theory seems in many respects closely modelled on Aristotle’s; but the view presented here of qualities entering or informing otherwise unformed matter may be seen as ultimately Platonic, based on the conception of matter and the receptacle in the Timaeus, while the terminology of “quality-less” (apoios) which he sometimes uses in this context is Stoic in origin (e.g. HNH I.3, 18; cf. the “matter (hulē) which underlies all the elements” at Hipp. Elem. 6, 114). The presence of an analogous concept is much less clear in Aristotle. Moreover, the precise relationship between specific element-bodies and specific element-qualities is somewhat confusing, both in terms of Galen’s explicit discussions of it and in terms of the relationship of his model to the Aristotelian and Stoic ones.