After dividing things immediately sensed from those sensed through them (e.g. color and shape are immediately seen, but health might be mediately perceived by a man’s color or shape) Hylas feels compelled to admit:
Hylas. To prevent any more Questions of this kind, I tell you once for all, that by Sensible Things I mean those only which are perceived by Sense, and that in truth the Senses perceive nothing which they do not perceive immediately: for they make no Inferences. The deducing therefore of Causes or Occasions from Effects and Appearances, which alone are perceived by Sense, entirely relates to Reason.
Philonous. This Point then is agreed between us, That Sensible Things are those only which are immediately perceived by Sense…
Aristotle and St. Thomas disagree, saying that what Hylas says are not sensed at all are in fact sensed per accidens. The distinction is important: newspapers are made to be read and not to beat animals or wrap fish, but they can be made to do both per accidens. The distinction raises any number of fascinating questions: is reasoning a sort of violence done to the sensible? What exactly does it add to sense, and how is this addition to be understood? How is intelligibility a possibility of sense information?
In all of this, it is important to keep in mind a distinction that the ancients (other than Plato) and medievals tended to overlook and which the Moderns saw more clearly: sensation, at best, cannot be perfectly objective. The thing causing sensation both gives an object and modifies/ gets a response from the organ, and the two are inextricably constitutive of the sense object as such. We cannot, for example, separate the sensation of an intense heat from pain or the sensation of a certain smell from its repugnance even though neither pain nor repugnance are features of the object.