A ristotle on Perception and Ratios

TLDR: A passage in De Anima III which has commonly been treated as echoing these sketchily indicated ideas has been shown to make no general claims about the nature of Xoyos at all, and none about O'La'O1OL considered as a faculty; that it deals only with instances of actualised perception, and those only of one specific kind; and that the variety of X6-yo; with which it is concerned is radically different as discussed by the authors.

Abstract: At several points in the argument beginning at De A nima 424a 17, Aristotle describes (x&'la00aLS as a Xoyos. This description has generally, and I think rightly, been taken to involve the sense of Xoyos as 'ratio', and it has been understood as being related to his earlier thesis (424a2 ff.) that O'Lrj ats is a prao6rls, a mean between sensible extremes. A'CoqLYs, in this context, is the faculty or capacity of perception, rather than the activity that goes on when we actually perceive: it is that by which we judge LaOw,r6t, not the act of judging or apprehending them (424a5-6); it is given a description jointly with ToL OTqTLXC4 E?Lvct, 'what it is to be capable of perceiving' (26-28); and the description itself is comprised in the words X6yos TLS Xxi MVXLLS. Two kinds of object, according to these passages, escape our perception, for quite distinct reasons. We do not perceive (ov'x acdaOotv6[Ox) what is Opws OEpFOV xot' vyXpov, fi oxXiqpo xai [taXaxoi (424a2-3): that is, apparently, we do not perceive e.g. the hotness or coldness of something that is itself at the same temperature as our sense-organ. Secondly, our aLOx) and pitch (6vos) of the strings is destroyed when they are struck too vigorously' (28-32). The first of these remarks suggests that we perceive through comparison or contrast: we judge or measure the relation between the condition of our sense-organ and the condition presented to us. The second, though its details are controversial, indicates that the properly balanced condition of our sense organs (ala ri ptx) may be disturbed by an excessive stimulus, to such an extent that they cease to function. There are many difficulties in these doctrines and their elaborations elsewhere, but it is not my intention to pursue them. My much more limited aim is to consider, against the background of these sketchily indicated ideas, a passage in De Anima III which has commonly been treated as echoing them. I shall try to show that it does nothing of the sort: that unlike the passages I have cited it makes no general claims about the nature of XaO'lOiav at all, and none about O'La'O1OL considered as a faculty; that it deals only with instances of actualised perception, and those only of one very specific kind; and that the variety of X6-yo; with which it is concerned is radically different.