on images vs encoding in the brain

Descartes establishes that we do not see by the direct transmission of images to the brain but by a coded version of the image;

"...you must conceive the nature of these images quite differently...for since [the philosophers] have no notion of the images except that they must be like the objects they represent, they cannot possibly explain how they can be produced by these objects, and received by the external sense-organs, and transmitted by the nerves to the brain. Their sole reason for the assumption is that they have noticed that a picture readily induces us to think of the object depicted, and have thus thought we must be led to conceive of the objects that affect our senses by tiny pictures formed within our head. But we have to consider that thought may be induced by many things besides pictures - e.g. by signs and words, which in no way resemble the things signified." Descartes: The Dioptrics (transl. Anscombe & Geach)

on the rational soul

In reference to the rational soul Descartes declares

"I had...described the reasonable soul, and shown that it could by no means be educed from the power of matter...but that it must be expressly created; and that it is not sufficient that it be lodged in the human body exactly like a pilot in a ship, unless perhaps to move its members, but that it is necessary for it to be joined and united more closely to the body, in order to have sensations and appetites similar to ours, and thus constitute a real man."

for a full text of The Discourse on the Method of Rightly Conducting the Reason, and Seeking Truth in the Sciences by Rene Descartes.