I have watched as much of Adam Schiff and company as I can bear, and I certainly do not intend to watch Jay Sekulow and Pat Cipolloni, so I shall spend some time this morning spelling out the new idea I had about Hume’s theory of knowledge and its relation to Kant’s theory in the First Critique. The idea is of general applicability, but I will just sketch it for the case of causal inference. This is going to be brief, and therefore perhaps somewhat incomprehensible to those who are unfamiliar with my interpretation of Kant.
Kant says at A106 that “A concept is always, as regards its form, something universal which serves as a rule.” The categories are second-order rules, or rule types. They are rules for forming rules for the synthesis of a manifold of sensibility. More precisely, as Kant makes clear in the First Edition so-called Subjective Deduction, they are rules for forming rules for the reproduction in Imagination of perceptions that are elements of the spatial manifold or diversity of sensibility. The act of reproduction imposes on the perceptions a rule-governed – hence in that sense a necessary, i.e., necessitated by the rule – temporal order.
Thus, the Category of Cause and Effect is a template, or rule type, for forming specific rules for the reproduction of certain elements of the manifold of sensibility in such a manner that some elements must, according to the rule, be reproduced first, and then other elements must be reproduced second. The Cause and Effect rule type differs in this regard from the Substance and Accident rule type, which specifies that each element can, indeed must, be reproduced first in one order and then in the reverse order. [The famous example of the boat and the house in the Second Analogy.]
Kant’s language breathes with the rigor and quasi-logical tonality characteristic of his predecessors among the Continental Rationalists, Descartes and Leibniz. It virtually commands us to stand at attention when we are reading the Critique.
Hume, in Part III of Book I of the Treatise, begins with a brief but devastating dismantling of the rigorous claims for causal inference advanced not only by Descartes and Leibniz but also, more significantly, by Newton. He then goes on to ask why it is, despite the manifest validity of this critique, that we believe judgments of causal connection. He asks what belief is, and how it comes about that we form and hold to such beliefs, a process that he labels “natural belief.” His account is casual, circumstantial, almost anecdotal, as though he were merely narrating what he has observed about the curious doings of the [British] human mind. It is an account best read while seated in one’s study with a fire in the hearth and a glass of port at one’s elbow.
His answer, to put it succinctly, is that the human mind has an inexplicable propensity, when presented in its experience with certain patterns of perceptions [the constant conjunction of resembling instances], to develop a disposition of a certain type. Specifically, the experience of repeated conjunctions of resembling perceptions triggers the propensity to form a disposition to expect an instance of the second type when presented with an instance of the first type, and, what is more, to confer on the idea of the anticipated instance a liveliness or force and vivacity, which is to say, to believe that it will occur.
In short, Hume’s analysis of causal inference is that it rests on an innate second-order disposition, a disposition to form dispositions of a first-order nature. Thus, structurally, Hume’s analysis of causal inference is almost identical with that of Kant.
This much occurred to me sixty-seven years ago as a nineteen year old Harvard senior taking his honors general examination in the Philosophy Department. It was elaborated in my doctoral dissertation, “The Theory of Mental Activity in Hume’s Treatise of Human Nature and Kant’s Critique of Pure Reason, and published sixty years ago as “Hume’s Theory of Mental Activity” in the Philosophical Review. But I never asked myself why, despite advancing such strikingly similar analyses of causal inference, Hume and Kant sound so utterly different from one another in the Critique and the Treatise. While re-reading Book I of the Treatise in preparation for my YouTube lectures, the answer occurred to me. It is hardly profound, indeed it is obvious, but I had simply never formulated it in my mind.
Hume and Kant end with strikingly similar analyses – rules for the formation of rules, propensities for the formation of dispositions – but they begin at polar opposite starting points. To put it as succinctly as I can, Kant starts with Leibniz and Hume starts with Locke. Each carries with him on his journey the baggage of his point of origin, each wears the clothing of his youth, sports the colors of his home team, each strives to remain true to his intellectual upbringing even as he is breaking completely with his past. That is why, more than two centuries later, we still cannot help seeing them as opponents, failing to recognize the deep similarity of their final doctrines.
Is there then no real difference between them? Indeed there is, a difference of monumental importance. What then is it? That is a subject for another post, but the answer can be given in five words: The Transcendental Unity of Apperception.