"Inner sense theory", Johansen began his BACAP lecture, "holds that we are conscious of our own perceptions by virtue of further perceptions which have those first perceptions as their object." He claimed that a correct analysis of De Anima 3.2.425 b12-25 reveals that Aristotle held such a theory.
Inner sense theory stands in contrast to Victor Caston's view ("Aristotle on Consciousness"), according to which each act of sensation of each sense organ carries with it, inherently, an aspect of reflexivity, so that it is an act of perception of a proper sensible, and an act of perceiving that we perceive, at the same time. Caston claims that it's his view that is supported by a correct analysis of that De Anima passage.
I propose to test these views by placing them in opposition to each other. In this case, the exercise will not be solely my own construction, since many of Johansen's remarks in his lecture were explicitly directed against Caston's interpretation and arguments.
Here I give the necessary materials: the Greek text, and the translations of Johansen and Caston. It will be seen that (roughly) Johansen takes the passage to be principally about faculties or sense-capacities (a 'capacity reading'); Caston takes it to be principally about the structure of perceptions (an 'activity reading').
GREEK TEXT (FROM TLG)
)Epei\ d' ai0sqano&meqa o3ti o(rw~men kai\ a)kou&omen, a)na&gkh
Since we perceive that we see and hear, it is necessary [b12] that one perceives that one sees either by sight (opsis) or by some other [sense]. But the same [sense] will be [b13] of sight and the underlying colour, so that either there will be two [senses] [b14] of the same thing or it [the sense] will be of itself. And furthermore, if indeed the sense of sight were different [b15], then either it will go on to infinity or some sense will be of itself, [b16] so that we should do this in the case of the first [sense]. But there is a puzzle (aporia): for if [b17] perceiving by sight is seeing, and colour or what [b18] has colour is seen, [then] something is going to see what sees (to horôn), then what first sees [or the first thing that sees] [b19] will also have colour. However, it is clear that perceiving by sight is not one thing; for even [b20] when we are not seeing, we discriminate both darkness and [b21] light by sight, but not in the same way. Moreover, what sees is actually (kai) coloured in a way [b22]: for the sense-organ is in each case receptive of the sense-object without [b23] the matter. That is why perceptions (aisthêseis) and appearances (phantasiai) are present in the sense-organs [b24] even when the sense-objects have departed.’
CASTON (b12-16 only)
Since we perceive that we see and hear, it is necessary either by means of the seeing that one perceives that one sees or by another [perception]. But the same [perception] will be both of the seeing and of the colour that underlies it, with the result that either two [perceptions] will be of the same thing, or it [sc. the perception] will be of itself. Further, if the perception of seeing is a different [perception], either this will proceed to infinity or some [perception] will be of itself; so that we ought to posit this in the first instance.
(I was not able to find in Caston's paper a translation of the remainder of the passage in accordance with the 'activity reading' .)