My son, Tobias [the law professor], despite having much more important things to do, has been reading my blog posts on the Critique, and last night sent me the following two questions, which I have decided to address in a special blog post before continuing with my series on Reading the Critique. Here is what he said:
"After reading the entries from yesterday and today, I have a better understanding of the types of question that Kant was attempting to answer. In many ways, of course, these questions are now the subjects of the experimental sciences -- neuroscience, experimental studies of perception, particularly in the case of damaged or physically altered brains, and the like. So, two questions for you.
First: What type of answers did Kant think that he was producing about the nature of perception and our knowledge of perception? Was he attempting to produce what we would now think of as scientifically rigorous answers, but in the absence of the scientific method? That is to say, if he were informed about the science of the brain and the experiments that have shed light on the processes of perception, would that information be relevant to him in assessing the correctness and usefulness of his answers? Or was he aiming at a different kind of answer (which I suppose one might describe as "purely conceptual")?
Second: How much, if at all, should the fundamental transformation in our understanding of matter, energy and physics -- again, based on experimental science -- impact the value that we see in Kant's Newtonian-focused inquiry? The Heisenberg Uncertainty Principle, for example, would seem to have something important to say about the relationship between the nature of things as they truly are and the nature of things as they interface with our perception. Is it pertinent to suggest that Kant must be reworked in light of our evolving understanding of physics? Or, once again, does that misconstrue the nature of the answer that Kant was attempting to produce?"
Well, you can see why I was a bit relieved when he grew up and left home! Let me address each of these questions in turn, even though the replies to some extent anticipate things I have not yet said about Kant's argument.
First Question: As we shall see, Kant's deepest argument rests essentially on a series of claims about the nature of consciousness, specifically its unity and what sorts of activity of the mind [viz synthesis] is required to produce that unity. Indeed, the entire deeper argument of Kant's philosophy rests on these claims. Now, Kant clearly thought that his arguments were philosophical and logical in nature and did not depend at all on contingent facts about the operations of the brain. But recent neurological investigations have raised doubts about these sorts of philosophical arguments. Let me give just one example. When I was a lad, analytic philosophers were quite taken with the notion of what they called "contrast-dependent concepts." By this they meant pairs of concepts like up/down, left/right, in/out, and even -- this was rather controversial -- right/wrong and good/bad. The general idea was that it was logically impossible to possess one of the concepts in any of these pairs without also possessing the other. Well, a brilliant and delightful neurologist named Oliver Sacks has published a number of books in which he recounts some of the weird and fascinating cases he has encountered of patients who have a variety of neurological deficits caused by tumors, traumas, and so forth. In one of his books, with the engaging title The Man Who Mistook His Wife For a Hat, he tells of a patient who, as a consequence of a brain tumor [if I recall correctly] had and could use the concept "left" but did not possess and could not use the concept "right." Asked to look for something on her right, she would turn slowly to the left until she had rotated all the way around and had come upon the object lying to her right. There are lots of other odd cases recounted by Sacks, including those of people who seem to have lost the unity of consciousness that Kant asserts is the absolutely fundamental presupposition of being conscious at all, and yet who are manifestly conscious and can carry on intelligent conversations.
I don't know, obviously, what Kant would have said about these facts had he known them, but they do seem to me to constitute a very serious challenge to his undertaking.
Second Question: I am even less knowledgeable about theoretical physics than I am about experimental neurology, if that is possible, but I will say something about this question. To some extent, Kant's arguments about mathematics and physical science are independent of the particular version of those disciplines he assumed to be cutting edge. Particularly with regard to the mathematics of space, Kant makes no effort whatsoever to "derive" Euclidean Geometry from his arguments about space and time as the forms of sensuous intuition lying a priori in the mind. His arguments are really designed to prove that there is some mathematics of space, and to explain its epistemological status [namely, as knowable A priori on the condition that it is limited to things as they appear to us, and is not extended to apply to things as they are in themselves.] But the situation is more complicated with regard to physics. As we shall see [if I can somehow manage to keep writing this thing, day after day], Kant's argument really does entail traditional full-scale determinism of the Newtonian sort. Indeed, as we shall see, Kant argues that to be empirically real just is to be an element in a deterministic chain of causes and effects. So although I am not sure that the Heisenberg Indeterminacy Principle poses a real threat to his argument, I think Quantum Mechanics very well may. A modern version of these sorts of considerations, it is my impression, led Einstein never to accept Quantum Physics as a satisfactory account of the nature of the universe. See the famous quote from a 1926 letter by Einstein to Max Born: "Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the "old one." I, at any rate, am convinced that He does not throw dice."
Where does all of this leave us? With regard to the second question, I am really utterly incompetent to judge whether philosophy or logic or anything else compels us to search for a classical interpretation of Quantum Physics. What Kant would have said is equally a mystery to me. I am less at sea about the first question. I remain convinced of the solidity of Kant's deepest arguments, despite the fascinating counter-evidence adduced by Sacks and other neurologists. Perhaps when I am finished "introducing" readers of this blog to the Critique, I can return to that question and address it again.