Science and the Immateriality of the Intellect

February 22, 2008 at 6:30 am (Uncategorized)

St. Thomas usually supports the first argument for the immateriality of the human intellect by using an example from the science of his time:

 It must necessarily be allowed that the principle of intellectual operation which we call the soul, is a principle both incorporeal and subsistent. For it is clear that by means of the intellect man can have knowledge of all corporeal things. Now whatever knows certain things cannot have any of them in its own nature; because that which is in it naturally would impede the knowledge of anything else. Thus we observe that a sick man’s tongue being vitiated by a feverish and bitter humor, is insensible to anything sweet, and everything seems bitter to it. Therefore, if the intellectual principle contained the nature of a body it would be unable to know all bodies (ST I q. 75 a. 2.)

The same argument, however,  can be supported by any scientific account of sensation. If one holds that eyesight is caused by an electromagnetic impulse, then if those same electromagnetic impulses all of a sudden became part of the constitution o the eye, then we would either see spots, or a jumble of things. Either way, our sensation would be harmed. In fact, if this condition of random electromagnetic stimulation of the eye arose in us spontaneously, we would consider it a disease, just as St. Thomas considers suffering under “feverish and bitter humors” a disease. Similarly, if the same sort of percussion waves that cause hearing arose on their own from some part of the ear, we go to the doctor to see what was wrong with our ears. The analogy holds just fine to the mind: if the same sort of bodies (or powers of bodies) that cause our knowledge were within mind as parts, then there would be something wrong with our mind. If mind is the activity of some organ, like hearing is the activity of that organ that goes from the auditory canal to the cochlea, then this organ of mind must have no physical parts.

Note carefully that the proof is not saying “What Knows X lacks X”- in that case the mind would not exist, because it know existence. The proof is rather that if the mind is a bodily organ (or the act of one) and therefore having bodily parts by nature within it, it would not know bodies. But the consequent is obviously false- in fact, the consequest must be considered false especially by a strict materialist! Even more, if mind were a bodily organ (or the act of one) and therefore having bodily parts, it would have to be by nature broken and diseased- just as a man’s ear would be diseased if it had a part that started emmiting a percussive sound wave.