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Kantās revolution1
Why start a revolution
When he died at the age of eighty on the February 12, 1804, Kant was as forgetful as Ronald Reagan was at the end of his life.2 To overcome this, he wrote everything down on a large sheet of paper, on which metaphysical reflections are mixed in with laundry bills. He was the melancholy parody of what Kant regarded as the highest principle of his own philosophy, namely that an āI thinkā must accompany every representation or that there is a single world for the self that perceives it, that takes account of it, that remembers it, and that determines it through the categories.
This is an idea that had done the rounds under various guises in philosophy before Kant, but he crucially transformed it. The reference to subjectivity did not conflict with objectivity, but rather made it possible inasmuch as the self is not just a disorderly bundle of sensations but a principle of order endowed with two pure forms of intuitionāthose of space and timeāand with twelve categoriesāamong which āsubstanceā and ācauseāāthat constitute the real sources of what we call āobjectivity.ā The Copernican revolution to which Kant nailed his philosophical colors thus runs as follows: āInstead of asking what things are like in themselves, we should ask how they must be if they are to be known by us.ā3
It is still worth asking why Kant should have undertaken so heroic and dangerous a task and why he, a docile subject of the enlightened despot the King of Prussia, to whom he had once even dedicated a poem,4 should have had to start a revolution. Unlike the causes that brought about the political revolutions of modern times, Kantās motives do not seem so very clear; yet, from a conceptual point of view, they turn out to be no less powerful and convincing.
Put simply, Kant too had no choice in the matter, given that philosophy as it was practiced at the time had reached a dead end, hanging between a blind empiricism and an empty rationalism; so much so that one of Kantās most famous mottoes, āthoughts without content are empty, intuitions without concepts are blind,ā5 for all that it is (as we shall see in nauseating detail) highly debatable as a theoretical stance, offers a very exact portrait of the historical situation for which Kant sought to supply a cure. Thus, we may begin trying to see which forces were in action on the philosophical scene in the second half of the eighteenth century.
The rationalists and the Library of Babel
The rationalists, many of whom were German professors, looked back to the great reconciler that was Gottfried Wilhelm Leibniz (1646ā1716). Suffice it to say that Leibniz dedicated himself to bringing harmony between Catholics and Protestants, to distracting Louis XIV from taking aim at Germany in favor of Egypt,6 and even to bringing peace between the modern philosophy that began with Descartes (1596ā1650) and the Scholasticism that drew inspiration from Aristotle. For this reason, rationalism can be identified in large part with the Schulphilosophie that brought medieval Scholasticism up to date with large doses of Cartesianism.
The rationalistsā underlying idea was that we know through concepts. Knowing what an object is amounts to being able to list its features: soul is an unextended thing, body is an extended thing, a dog is a soulless domestic quadruped. In this spirit, the composition of a book of metaphysics is roughly the orderly formulation of definitions that are then combined in rational form so as to avoid contradictions. By the systematic aggregation of concepts, it becomes possible to realize the dream, first conceived in the Middle Ages by Raymond Lull (1232ā1316) and then renewed in the Renaissance and in Descartesās time, of a ācombinatorial artā that promised universal knowledge by means of the composition of concepts and, ultimately, of words.7
How was an art of this sort supposed to work? And, above all, did it work? Suppose we have to determine how many angels can dance on a pinhead. By definition, millions, given that, as we read in the dictionary, angels are pure spirits and have no body. Thus we have a ready answer: as many angels as you like can dance on a pinhead, just as there are infinitely many lines that pass through a point. If anyone objected that he had never seen an angel, the obvious answer would be that of course he hadnāt because angels, being unextended, cannot be seen. This would not be a quip or a manner of speaking. Leibniz had elaborated a theory according to which the actual world, the one in which Julius Caesar crossed the Rubicon and John Lennon was shot by a fan, is just one possibility among very many that has been brought about, so that a complete metaphysics should concern itself with all the possibilities that do not contain a contradiction.8
Kant loathed this way of doing metaphysics. He was curious about the sciences and about travel, even though he himself never left Kƶnigsberg and its immediate environs, and he did not believe that dictionaries add anything to our knowledge. Moreover, he inherited a hatred for intellectualism from his professor of philosophy, Martin Knutzen (1713ā1751), an early critic of hyper-rationalism. This is the source of his accusation against the Leibnizians that they did nothing but spin and weave purely nominal definitions in such a way that their metaphysical works were, at best, dictionaries and, at worst, fantasies born out of the combinations of words.
In his famous short story āThe Library of Babel,ā9 Jorge-LuĆs Borges (1899ā1986) illustrates the perverse brew that can come out of mixing the idea that the real is only one of the ways that possibility can manifest itself10 with the dream of a combinatorial art doomed to speculate on the supposed advantages for knowledge gathering promised by the purely formal assemblage of the infinite resources of what is mere possibility. In that endless library, which contains all the combinations of the letters of the alphabet, there is, mixed in with all the infinite senseless books, everything, including the things we donāt know (such as precisely what Caesar was thinking as he crossed the Rubicon and how many people there were in Rome that day), which is all to the good. But there is also the opposite of everything: a Caesar who does not cross the Rubicon, Rome defeated by Carthage, Caesar as Alexander the Greatās grandfather, Hitler the philanthropist. Because we have no way of telling the true from the false, the library is useless; indeed, it would be better if it didnāt exist, because most readers never had the luck to read a single passage that made full sense.11
Given that we are not stuck in the library of Babel, Kantāalong with others who at the time began criticizing Leibniz12ācould not draw inspiration from Borges. But the kernel of their dissatisfaction is this: how can we tell true from false unless we move from the world of mere possibility to that of actuality? And what is actuality unless it is primarily what we encounter in space and time or, as Hamlet had it, in heaven and earth? Kant observes13 that there is a great difference between mathematics and metaphysics, a gap that the Leibnizians underestimated. Using the combination of symbols (Kant speaks of āconstruction,ā but the idea is the same14), I can reach fine results in mathematics. I can take a number at random, say 123, multiply it by another, 321, and get 39,483. The result is absolutely exact, and Iāll get it every time I do the sum.
The trouble, nevertheless, is that mathematics is not knowledge,15 because for Kant knowledge is formed from the encounter between concepts and the sensations that are produced by something that is physically real. Prior to that, one can think, which is a fine thing and can furnish some right answers, but it is different from knowing, as is easily demonstrated by considering the difference between thinking of a clock and looking at one in order to know what time it is. Thus, I have knowledge when I know, for instance, how many grains of wheat there are in a sack (say, 39,483), but not when I multiply 123 by 321. And the Leibnizians did not notice this difference because they were misled by the idea that there is no difference in kind between sensibility, which perceives things, and intellect, which thinks them, but only one of degree of clearness and distinctness.16 Thus the supporters of rationalism behave like mathematicians when they do metaphysics insofar as they regard everything that is not contradictory as true.
From the point of view of concept-formation, there is nothing implausible about thinking, say, that Henri Bergson read the adventures of Flash Gordon (perhaps there would be a contradiction in his being a fan of Dylan Dog). Except that it isnāt true or, more cautiously, we donāt know that it is. And we canāt build theories on the basis of such wild hypotheses, because mathematics seems clear and intuitive while the concepts are much less so, whether they refer to concrete objects17 or to abstract notionsāabout which we may be completely in the dark. For instance, what exactly are we referring to when we speak about āfreedom?ā Kant rightly notes that most people, if not all, do not know exactly what they are saying when they use so vague a word.18
So as not to let metaphysics run unbridled, the maxim of prudence will then be not to compare one concept with another but, insofar as it is possible (and it is obviously not possible in all cases), to compare concepts with objects. If this is the cure, it would seem that it was the empiricists who had pointed to the right path to take, and Kant credits the leading empiricist of the day, David Hume (1711ā1776), with having woken him from the ādogmatic slumbersā19 into which he and a fair number of German professors had fallen.
The empiricists and Funes the Memorious
The basic idea of the empiricists was that all of our knowledge is derived from the senses: in the world, I encounter sensations and not concepts. Hence we can happily do without the purely conceptual organization of the universe that metaphysics offers. For instance we have the concept of ācause,ā but if we hadnāt seen, say, a window that, as it opens, makes a vase fall, we would never have conceived of anything as a cause and we would not have included it in our dictionary. Likewise, we suppose that space has three dimensions: length, breadth and depth; but if we were subject to sensory deprivation, we might well not come up with the concepts of length and breadth. To say nothing of depth, which is not obvious even when we are endowed with senses and which calls for some supplementary experience: the man whom we now see as big because close was a dot on the horizon, and if we hadnāt approached him it might not have occurred to us that, in addition to wide and high there is also the far and the near, that is, depth.
The moral that the empiricists drew was that, not just from the point of view of concept formation (as Kant would admit), but absolutely speaking; that our knowledge does not derive from concepts but rather from the sensible experience that is laid down by habit and reasoning. And concepts are just one quick, and often deceptive, way in which to codify that experience. Substance does not exist, but is the mere conjecture of a substrate that could exist without its accidents.20 A cause is not a principle, but arises only from the fact that we often see one event follow another, and we think that the first determines the second.21 The āIā is a mere bundle of sensations and not the unextended substance that Descartes thought it was.22 At least one spatial dimension, depth, derives from experience.23
The empiricists, however, had trouble grasping that you can go some way without metaphysics, but not very far. And if we think of cause and substance, the self and space as mere upshots of our experiences, then philosophy, science, and morals are doomed to disappear, because the whole world crumbles in our hands. For a radical empiricist, everything is, in the long run, vain, and empiricism becomes the last stop before skepticism. After all, it is futile to inquire into the nature of things given that sooner or later they could change, and there is no deep difference between the laws of physics and the train timetable. These are the traditional and besetting problems of relativism, which does not necessarily need a justification of this sort.24 The three biggest problems for the empiricists of the seventeenth and eighteenth centuries were certainty, the move from particular sensations to general ideas, and the relation between ideas and the things to which they referred.
The problem of certainty was the most alarming. Based on past experience, a turkey can conclude that every time the farmer comes, it will eat; but the day will come when the farmer will wring its neck. Given that, for the empiricist, all our knowledge, both of big things and small, is inductive, we are all in the position of the turkey: the law that makes the bulb light every time I switch the switch is limited by the fact that in the end the bulb will blow. Following this line, we ought even to doubt that the Sun will rise tomorrow (which will happen sooner or later). In this state of things, astronomy is a science that is uncertain, or at best a bit more credible than astrology. And this is a not entirely unwelcome conclusion, given that the empiricists developed this line of thought with a subtly antiscientific aim, seeking a residual space for philosophy. But nor is it terribly comforting.
From the practical point of view, the problem of general ideas was less pressing, but it generated serious theoretical difficulties. The empiricists could hardly deny that we have, in addition to the sensible impression of this dog, also the idea of a dog, which is applied to various instances of small dogs, big dogs, quiet dogs, barking dogs, dogs walking, and dogs at rest. But how do we get from the impressions to the idea? One suggestion is that we get there by a sort of mixture that makes perception more vagueāHume would say āenfeeblesāāand that combines it with others: from on...