Appendix 4.

(453) [Intellective and sense perception]

Intellective perception of bodies bears no likeness to sensation. But has bodily sense perception any likeness to the intellective perception of bodies? I maintain that there is a strict relationship between these two perceptions, but no relationship of likeness.
In bodily sense perception, it is not the body which is perceived, properly speaking, but an experience terminating in an outside agent. In intellective perception of bodies, the opposite is true: the body itself is perceived as an object acting in us. The two perceptions are contraries, just as passive experience and action are contraries.

Passive experience and action are opposed as such, but the understanding, when disregarding the particular, contrary relationships with the experiencer and agent, considers them as one and the same thing.
The nature of the understanding is to perceive things in themselves; it is not limited to perceiving their relationships. When the understanding has perceived the thing we are discussing (that is, the change taking place in us) as it is in itself, it also finds an association between experience and action; it has perceived their link, that is, the thing which is capable of two contrary relationships. This explains the association between bodily sense perception and the intellective perception of bodies.

Sense perception is an element (matter) of intellective perception. Intellective perception, composed of matter and form, cannot be said to resemble sense perception which is subordinate to and an element of intellective perception; it is neither equal to nor a copy of intellective perception. Thus, we do not normally say that a particular mouth is like the head containing the mouth, just as we do not normally say that the square shape of some particular object resembles the substance of the object, although the body is square in shape.
Nevertheless, the relationship between a bodily sense perception and the intellective perception of that body is so
lose that with each perception we perceive the same thing identically although in a different mode. With intellective perception we perceive in a universal mode what we perceive in a particular way with sense perception. The intellect adds being, that is, it adds the cause to the effect perceived by sense.