See Also: Sense and Science: An Aristotelian Perspective
Aristotle was a great philosopher, but he died well over two millennia ago. We, as the living and breathing members of the human species, must learn to move past outdated systems of thought. And yes, Aristotle's system of thought is entirely outdated. He thought he demonstrated that time had no beginning; he was wrong. He thought he demonstrated that there were only four elements; he was wrong. He thought he demonstrated that the earth was the center of the universe; he was wrong. He thought he demonstrated that space did not exist; he was wrong. He thought he demonstrated that the stars and the sun moved in perfect circles around the earth, themselves being constituted of a fifth element entirely non-existent in the sublunar sphere. With all of these errors, formerly thought to have been demonstrated, what can we expect to remain standing?
There are numerous individuals, almost if not universally religious, that fighting tooth and nail, still manage to approach the writings of this philosopher with an absurd degree of dogmatism. "Sure, he was wrong when it comes to science stuff," they might say, "but he was still right about motion, change, causality, the uncaused first cause, sensation, epistemology etc."
I assure you, there will be more responses forthcoming, but here I intend only to address Aristotle's understanding of sensation, thereby laying the groundwork for dismantling the entirety of his epistemology and his conclusion that we have immaterial souls.
As a matter of fact, daunting though this task may sound, it is not very difficult to do: Nothing more is required to come to this conclusion than to see two of Aristotle's most important claims concerning the topic and two of the most easily grasped, scientifically verifiable, claims of neurology. This same doctrine of sensation is at the basis of the hylomorphic argument for the immaterial soul, which relies on the same two premises that I here enumerate, and without them the whole of their epistemology goes caput. Indeed, even the claim of the immateriality of the rational soul loses its grounding. This indeed, is a project worth undertaking.
So let’s go ahead and enumerate some things we think we know:
It should be sufficiently clear to the reader that in the last article, (2) was tacitly abandoned as a principle in Sense and Science to manufacture a false consonance between Aristotle and neurology. If sensation arises from the disturbance of an electrical mean, and we sense by receiving electrically-charged matter, what is important for allowing sensation is not that the organ lacks the form that it senses, but that it lacks the electrical charge that it is receiving. This is a serious problem for the Aristotelian. This problem, moreover, with very little work, can be shown to produce inevitable logical contradiction.
When we say, “Nothing receives what it already has”, this is certainly true with respect to electrically charged matter (a neuron cannot receive an ion that was already within the neuron, or it would not be receiving it at all), but do we take this statement only with to ions? If so, we abandon (1). To both the ions and to the sensible forms then. To keep with Aristotle, we assume (2) is correct and then ask whether or not sensation is in the brain. If not, then we would be forced to contradict (3), and if so, we would be forced to contradict (4). But (3) and (4) are certainly true.
(1) or (2), are essential elements of Aristotle’s doctrine on sensation, being necessary for his argument for the immaterial soul and for his epistemology, yet they cannot be held without contradiction or all-out denial of fact. Aristotle was a brilliant man in the 300's BCE, but his doctrine of sensation must now be abandoned.