A Brief Rebuttal of Aristotle's Theory of Sense

And you as well must die, belovèd dust,
And all your beauty stand you in no stead;
This flawless, vital hand, this perfect head,
This body of flame and steel, before the gust
Of Death, or under his autumnal frost,
Shall be as any leaf, be no less dead
Than the first leaf that fell,this wonder fled,
Altered, estranged, disintegrated, lost.
Nor shall my love avail you in your hour.
In spite of all my love, you will arise
Upon that day and wander down the air
Obscurely as the unattended flower,
It mattering not how beautiful you were,
Or how belovèd above all else that dies.
​“And you as well must die,” Edna St. Vincent Millay

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 We, as the living and breathing members of the human species, must learn to move past outdated systems of thought. And yes, Aristotle's system of thought is entirely outdated.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:

1. Because of his radical doctrine of sensory objectivity, Aristotle was certain that there must be an identity between the form received in the sensing power and the form given by the sensed object.
2. Aristotle thinks that no sensing organ can have the form that it senses when it is not sensing. For nothing receives what it does not have, but every sensation is a reception of a form of the sensed object.
3. In light of cochlear implants, devices which can replace everything in a human ear up to the auditory nerves, it is sufficiently well proven that sensation happens in the brain. The only thing your nervous system needs to sense is the right combination of electrical impulses in the right places.
4. You can sense someone else’s brain, and if you cut off the top of your skull and set up enough mirrors, you could even look at your own brain, even the visual cortex. You can feel your brain and smell your brain; in theory you could (but please don't) even taste your brain, and in short, your brain is certainly capable of being sensed both by itself and by similarly constituted pieces of matter.

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.