From an appendix of a forthcoming Veriphysics book:
Immanuel Kant wrote devoted an entire chapter to amphiboly. It is titled “On the Amphiboly of the Concepts of Reflection” (Amphibolie der Reflexionsbegriffe), and it ends the Transcendental Analytic of the first Critique at A260-292 / B316-349. In this chapter, Kant develops a technical diagnostic for a specific kind of philosophical error: the confusion that arises when a key concept operates in two distinguishable senses, with an unargued inference between them, thereby generating systematic distortion in the resulting metaphysics. He applies this diagnostic to Leibniz…
Leibniz, according to Kant, operated entirely within the domain of pure understanding. He treated the concepts of reflection as if they applied to things in themselves, considered through reason alone, and then transferred his conclusions to objects of experience without noticing that the conditions of application had changed. The result was the metaphysics of monads, pre-established harmony, and the identity of indiscernibles.
Take the example Kant develops most fully. Two drops of water, considered through pure understanding, are identical if their concepts contain the same determinations. Leibniz’s principle of the identity of indiscernibles follows: if two objects are conceptually indiscernible, they are numerically the same object. But when the two drops are given in sensible intuition, in space, the difference of their spatial positions is sufficient for numerical difference regardless of conceptual identity. The principle holds for objects of pure understanding. It does not hold for objects of experience. Leibniz “took the appearances for things in themselves” (A264/B320) and applied a principle valid for the one to the other.
The same pattern repeats across all four concepts of reflection. Realities in pure understanding cannot oppose each other; realities in experience can (two forces pulling in opposite directions produce zero net motion). The inner in pure understanding is what has no relation to anything external; the inner in experience is always a matter of further relations. Matter precedes form in pure understanding; form precedes matter in sensible intuition. In every case, Leibniz’s error is the same: treating a conclusion valid within pure understanding as if it held for experience without performing the transcendental reflection that would have revealed the different conditions of application.
Kant summarizes the error in a single sentence at A271/B327: “Leibniz intellectualized the appearances, just as Locke totally sensitivized the concepts of understanding.” The diagnostic is that a key concept operating in two distinguishable domains has been applied across domains without acknowledgment that the conditions of application differ. The inference between domains is not argued for. It is performed by treating the concept as if it were univocal when it is not.
Kant appears to regard this diagnostic as one of his central contributions. It is not a minor appendix to the Analytic but the correction that clears the ground for the critical philosophy. The rationalist metaphysics of the seventeenth century rested, in Kant’s account, on a systematic amphiboly, and identifying the amphiboly was the first step in replacing the rationalist framework with the critical one. “For just this reason,” Kant writes at A270/B326, “the exposition of the deceptive cause of the amphiboly of these concepts, as the occasion of false principles, is of great utility in reliably determining and securing the boundaries of the understanding.”
The diagnostic Kant applies to Leibniz also, as it happens, can be applied to Kant himself…
And for an answer to a question concerning this raised on SG, there is more at Veriphysics.
