INCOMPREHENSIBLES — CORNER 243 



terms and thus to destroy the humanities and do away before long 

 with the arts and all learning, except physics. 



In reply to the professor's question, I say in the first place that we 

 anatomists, physiologists, and biochemists are for practical reasons 

 bound to work on the assumption that the animals and parts of ani- 

 mals we study are indeed mechanisms. We must try as hard as we can 

 to bring all animal and human behavior under observation and meas- 

 urement. If the premature acceptance of nonphysical "vitalistic'- 

 forces leads us to abandon physical and chemical investigation, we 

 shall only wander in a no man's land of conjecture. 



In the second place, the progress of these sciences brings into the 

 realm of materiality much that was once thought to be immaterial. 

 One example of this will suffice. The phenomenon of vision was a 

 great enigma to the ancients. Aristotle himself cried out in wonder- 

 ment, "Wlio would believe that so small a space (as the eye) could 

 contain the images of all the universe? What skill can penetrate 

 such a wonderful process? This it is that leads human discourse to 

 the consideration of things divine!" Since then we have marched 

 steadily toward understanding human seeing as a physical and chemi- 

 cal activity. In Aristotle's time and in the Middle Ages, all existing 

 knowledge was encompassed in a vague concept of the eye as the lan- 

 tern of the soul. Wliat we now call the lens was believed to be the 

 central receptor of things seen, passing visual images inward to the 

 soul itself. That the eye is a camera working on strict optical prin- 

 ciples, and the retina its photoreceptor, became clear in the seventeenth 

 century. In another hundred years, discovery of the optical nerve 

 fibers made known that the brain is involved in the process of vision. 

 The actual areas of the brain concerned in seeing, and the exact path- 

 ways from the retina to the cortex, were worked out in the nineteenth 

 century ; the biochemistry and biophysics of nerve conduction are the 

 work of our own age. In view of all this progress toward a physico- 

 chemical concept of the visual process from eye to brain cortex, should 

 the biologist be thought too daring if he now expects that biophysics 

 will one day explain the conversion of cortical optic responses into 

 conscious thought, and trace all the channels over which they rever- 

 berate throughout the body, causing the seer to stare or tremble or soar 

 in ecstasy at what he sees ? 



We are indeed daring, I admit, when we predict that consciousness 

 will be explainable in physicochemical terms, but nowadays even those 

 who doubt the possibility of such understanding usually base their 

 doubts not on grounds of vitalism or of piety, but on a materialistic 

 argument involving a sort of uncertainty principle which states that 

 a thinking machine is necessarily incapable of perceiving how it 

 thinks. 



