There must be nearly as many Kants as there are serious readers of the philosopher. I belong to the katechoumenoi: I am a convert, and I believe there are not many such. Kant, especially in the first Critique, offers a system, and I think he says that the whole edifice must fall if any fault be found in it. In English-speaking countries where the analytical tradition dominates, it is customary to raid those crumbling, though perhaps still imposing ruins for their masonry; that is, the arguments stand on their merits, which are suspect, and have value iff they are sound. ‘Kantians’ are like the followers of Freud, each to his own school and improved system. Kleist famously shot himself because of the despair provoked by reading the Critique of Pure Reason, but (it is generally accepted) he got it wrong. It’s a difficult book.
Possible readings can perhaps be divided into three regions (like Gaul): empiricist, rationalist, and idealist, in other words, they cover the entire terrain of philosophy. I’m not well-versed in the reception of Kant after the eighteenth century, but idealist reworkings of Kant seem to cover most of the nineteenth century in Germany. I’m in the empiricist camp, seeing his entire purpose as having been to close the door on such speculations; and I find the building imposing, unmoved by any cracks or gaps. But when I think of ‘Kantianism’ today, it’s figures like Chomsky and Stephen Pinker that come to mind. They would perhaps not claim to be followers of Kant, but the influence is clear though with a different emphasis from the original.
I am no philosopher, and my original encounter with Kant was as an intellectual historian. It’s got to be illuminating to place any thinker against his context, see what he was reacting to, and how he understood his own contribution. The Preface to the first Critique, with its metaphor of the ‘Wohnhaus’, or humble abode of reason, is actually pretty clear. We can kill idle speculation dead by keeping our feet on the ground. If what we know comes from the evidence of our senses, we can’t say either way how the universe began or whether there is a God. (Such questions were still dynamite, so had to be skirted around). The problem with this was Hume, who had argued that you couldn’t make much sense of the world, in particular, it was not possible to establish causation. Surely it should be possible to explain a bit more than that, without letting the mediaeval fancies back in? Kant’s innovation was to argue that experience of anything at all is only possible if it is structured in various ways (most notably through causation): otherwise nothing makes sense. That explanation would probably attract red ink in an undergraduate essay, but it is not my aim to offer a lucid summary; there is no substitute for reading Kant at first hand. The argument has the same structure as that of the second Critique: if experience is possible at all it must have this shape; if there is morality it must be internally consistent, else it would not be morality, therefore it must unfold to contain justice, equality and so on, with a certain cut of the sails that is distinctively Kantian.
Kant was thinking of human beings, but I think his argument applies to Martians, and spiders, too: this is what experience as such must be like. The contemporary rationalists believe that our modes of thought are hardwired, and therefore species-specific. Clearly, our sense organs have certain limitations (a range of wavelengths for both sound and vision, for instance) and there is some flesh-and-blood plumbing in there to make sense of it all. But I would like to believe the Martians must do very much the same thing by other means, unknown to us.
And so finally I come to my point, just a speculative trifle. All this favours the sense of sight. On the whole, the other senses are much blunter instruments. The sense of touch (divided perhaps into proprioception, pain, temperature, sexual sensation, etc) tells more about our own body, and only indirectly anything external; and maybe taste and smell are a bit like this too. But what about hearing? I don’t mean that we can hear, say, certain sounds that speak of the burn rushing through the glen, though it is immediately interesting that what those sounds convey naturally falls into visual shape. Through our ears comes language, and with it a set of beliefs, attitudes, dispositions, and social capacities we can no more shake off than the urge to duck when a cricket ball comes at us.
There is a body of theological argument that we imbibe faith with the mother’s milk of human kindness. I bristle and can feel my readers bristling at the very thought, because of the obvious problems of relativism and authority. But what if there were a Kantian bootstrapping argument, that there must be — what? Some form of social order? Some sense of ‘self’ and ‘other’ and a mode of communication between them, or at least recognition? Some body of shared beliefs, perhaps amounting to ‘culture’? It being possible for these to be more or less elaborate, with perhaps a canonical minimum case (the mating behaviour of the praying mantis)? Just as there must be things, perhaps, there must be social objects, which in turn must satisfy some criteria to be capable of functioning as such? Like: continuity of identity through time despite change? A presumption of trustworthiness? Having an opaque ‘inside’ that must be mediated to the world through deliberate utterance? The mantis would never copulate if it were unable to conceal its final intentions.
It certainly seems to be the case that Robinson Crusoe can’t exist without Friday. A man on a desert island, without language or intercourse, in some sense ceases to exist as a human being. A more mundane but frequent example is lonely old people driven mad by isolation. Perhaps this is something that is a matter of degree: social exclusion, due to class (McJobs), or a stigmatised identity (ex-cons), diminishes and brutalises the individual.
Here is what looks like a good account of the central ‘move’ on Kant’s part: