Nevertheless, Kant believed in the evidence of phenomena, he believed that our sensible intuitions came from somewhere, and he was concerned to articulate a rebuttal of idealism. But it appears to have been Hume who roused Kant from his dogmatic sleep, problematizing the causal relationship between things, and not Locke, though it was Locke who brought to the table the problem of an activity of the intellect in the naming of things.
A fundamental problem for the empiricists was saying why we decide, upon receiving sensible impressions from something, whether they refer to a tree or a stone. Yet it seems to have become a secondary problem for Kant, who was too preoccupied with guaranteeing our knowledge of heavenly mechanics.
In fact, the first Critique does not construct a gnoseology so much as an epistemology. As Rorty (1979) sums it up, Kant wasn’t interested in knowledge of but in knowledge that: not, then, in the conditions of knowledge (and therefore the naming) of objects. Kant asked himself how pure mathematics and physics are possible, or how it is possible to make mathematics and physics two theoretical fields of knowledge that must determine their objects a priori. The nucleus of the first Critique concerns the search to provide philosophical warrant for a legislation of the intellect regarding those propositions that have their model in Newton’s laws—and that, out of the need for exemplification, are sometimes illustrated by more comprehensible and venerable propositions such as All bodies are heavy. Kant is concerned to guarantee the knowledge of those laws fundamental to nature, understood as the totality of objects of experience. But he appears uninterested (at least until his Critique of Judgment) in clarifying how we know the objects of daily experience, what nowadays we call natural kinds, for example, camel, beech tree, beetle—with which the empiricists, on the other hand, were concerned.
Husserl, a philosopher interested in knowledge of, realized this, with evident disappointment (Investigation VI, ch. 8, para. 66):
In Kant’s thought categorial (logical) functions play a great role, but he fails to achieve our fundamental extension of the concepts of perception and intuition over the categorial realm.… He therefore also fails to distinguish between concepts, as the universal meanings of words, and concepts as species of authentic universal presentation, and between both, and concepts as universal objects, as the intentional correlates of universal presentations. Kant drops from the outset into the channel of a metaphysical epistemology in that he attempts a critical ‘saving’ of mathematics, natural science and metaphysics, before he has subjected knowledge as such, the whole sphere of acts in which pre-logical objectivation and logical thought are performed, to a clarifying critique and analysis of essence, and before he has traced back the primitive logical concepts and laws to their phenomenological sources.3
Husserl’s disappointment is converted into satisfaction for someone who maintains instead that the problem of knowledge can be resolved only in terms internal to language, namely in terms of coherence among propositions. And here Rorty (1979: sect. 3.3) takes issue with the idea that knowledge must be “the Mirror of Nature,” and he even asks how it was possible for Kant to assert that intuition offers us the manifold, when this manifold is known only after it has been unified in the synthesis of the intellect. In this sense, Kant would have taken a step forward with regard to the gnoseological tradition going from Aristotle to Locke, a tradition in which philosophers attempted to model knowledge on perception. Kant would have liquidated the problem of perception, insisting that knowledge concerns propositions and not objects.
Rorty’s satisfaction has evident reasons: although he proposes to challenge the very paradigm of analytical philosophy, it is this paradigm that is his point of departure, and therefore Kant seems to him to have been the first to suggest to the analytical tradition that we should not be asking what a dog is but rather what follows if the proposition dogs are animals is true.
What Rorty seems not to consider is that, if the opposition is between knowing what X is like and knowing what type of thing X is (as he himself quotes Sellars), we would still have to ask how one could respond to this second question without having responded to the first one.4 And it is worthwhile asking ourselves to what extent the opposition cited reproposes the old question (treated in Chapter 1 of the present volume) between encyclopedia and dictionary knowledge.
Kant’s position is still more embarrassing. He not only appears uninterested in explaining how we understand what X is like, but also incapable of explaining how we decide what type of thing X is. In other words not only is the problem of how one understands that a dog is a dog and not a cat absent from the first Critique, but even the problem of how we are able to say that a dog is a mammal.
More than of a lack of interest on Kant’s part, we should perhaps speak of a cultural difficulty.5 Kant, as an example of rigorous knowledge constructible a priori, had mathematical and physical sciences at his disposal, as established and laid down from Newton onward, and knew very well how to define weight, extension, force, mass, a triangle, and a circle. On the other hand, he did not have at his disposal a science of dogs, beech or linden trees, or beetles. When Kant writes his first Critique, hardly more than twenty years had passed since the definitive edition of Linnaeus’s Systema naturae, the first attempt to establish a classification of natural species.
The older editions of the classic Italian dictionary first published in 1612 by the Accademia della Crusca still defined a dog as a “well-known animal,” the attempts at universal classification like those of Dalgarno or Wilkins (seventeenth century) used taxonomies that we would today call approximate (as we have seen, in this volume, in both Chapters 1 and 11. This is why Kant spoke of empirical concepts, and often repeated that we couldn’t know all of the marks of these concepts. To take up our main point again, he was concerned by the fact that encyclopedic knowledge was potentially infinite. Thus the first Critique opens (Introduction, VII) with the declaration that concepts containing empirical elements must not appear in transcendental philosophy. The object of an a prior synthesis cannot be the nature of things, which in itself is “unlimited.”
But even if Kant had been conscious of reducing knowledge to knowledge of propositions (and hence to linguistic knowledge), he still would not have been able to formulate the problem, which Peirce on the other hand will formulate, of the nonexclusively linguistic but semiosic nature of knowledge. To be more precise, if he fails to do so in the first Critique, he will move in this direction in the third. But to be able to set out along this road, he needed to bring the notion of schema into the picture.
According to one of Kant’s examples, you can go from an unrelated succession of phenomena (there is a stone, it is struck by the sun, the stone is hot—and, as we will see, this is an example of perceptual judgment) to the proposition the sun heats up the stone (P, 23). Let us suppose that the sun is A, the stone B, being hot C, and we can say that A is the cause by which B is C.
The tables of categories, transcendental schemata, and principles of the pure intellect instruct us on how to proceed. The axioms of intuition tell us that all intuitions are extensive quantities and, through the schema of number, we apply the category of singularity to A and B. Through the anticipations of perception, applying the schema of Degree, the reality of the phenomenon (in the existential sense of Realität) supplied by our intuition is affirmed. Through the analogies of experience, A and B are seen as substances, permanent in time, to which accidents inhere. We therefore establish that accident C (heat) of B (stone) is caused by A (sun). And thus we finally decide that what is connected to the material conditions of experience is real (reality in the modal sense, Wirklichkeit) and applying the schema of existence in a determined time, we assert that the phenomenon is truly the case. Likewise, if the proposition was by the law of nature, it happens that always and necessarily the light of the sun heats up (all) stones, the category of unity should first be applied, and finally that of necessity. Accepting the transcendental foundation of synthetic judgments a priori (but this isn’t the matter in contention), Kant’s theoretical apparatus has explained to us why one can say with certainty that A necessarily causes the fact that B is C.
But why is A perceived as sun and B as stone? How do the concepts of the pure intellect intervene to make it possible to understand a stone as such, as distinct from the other stones in the heap of stones, from the solar light heating it up, from the rest of the universe? The concepts of the pure intellect that constitute the categories are too vast and too general to allow us to consent to recognize the stone, the sun, and the heat. Kant promises (CPR/B: 94) that once a list of pure primitive concepts has been designated, we will “easily” be able to add those derived
