Lastly, Kant emphasises the fact that the method of the Critique must be akin to that of dogmatism. It must be rational a priori. To adopt any other method of procedure is “to shake off the fetters of science altogether, and thus to change work into play, certainty into opinion, philosophy into philodoxy.”[119] And Kant repeats the claims of the preface of the first edition as to the completeness and finality of his system. “This system will, as I hope, maintain through the future this same unchangeableness.”[120]
Logic.[121]—For Kant’s view of the logic of Aristotle as complete and perfect, cf. below, pp. 184-5. Kant compares metaphysics to mathematics and physics on the one hand, and to formal logic on the other. The former show the possibility of attaining to the secure path of science by a sudden and single revolution; the latter demonstrates the possibility of creating a science complete and entire at a stroke. Thanks to the new Critical method, metaphysics may be enabled, Kant claims, to parallel both achievements at once.
Theoretical and practical reason.[122]—Such comment as is necessary upon this distinction is given below. Cf. p. 569 ff.
Hitherto it has been supposed that all knowledge must conform to the objects.[123]—This statement is historically correct. That assumption did actually underlie one and all of the pre-Kantian philosophies. At the same time, it is true that Kant’s phenomenalist standpoint is partially anticipated by Hume, by Malebranche and by Leibniz, especially by the first named. Hume argues that to condemn knowledge on the ground that it can never copy or truly reveal any external reality is to misunderstand its true function. Our sense perceptions and our general principles are so determined by nature as to render feasible only a practical organisation of life. When we attempt to derive from them a consistent body of knowledge, failure is the inevitable result.[124] Malebranche, while retaining the absolutist view of conceptual knowledge, propounds a similar theory of sense-perception.[125] Our perceptions are, as he shows, permeated through and through, from end to end, with illusion. Such illusions justify themselves by their practical usefulness, but they likewise prove that theoretical insight is not the purpose of our sense-experience. Kant’s Copernican hypothesis consists in great part of an extension of this view to our conceptual, scientific knowledge. But he differs both from Malebranche and from Hume in that he develops his phenomenalism on rationalist lines. He professes to show that though our knowledge is only of the phenomenal, it is conditioned by a priori principles. The resulting view of the distinction between appearance and reality has kinship with that of Leibniz.[126] The phenomena of science, though only appearances, are none the less bene fundata. Our scientific knowledge, though not equivalent to metaphysical apprehension of the ultimately real, can be progressively developed by scientific methods.
The two “parts” of metaphysics.[127]—Kant is here drawing the important distinction, which is one result of his new standpoint, between immanent and transcendent metaphysics. It is unfortunate that he does not do so in a more explicit manner, with full recognition of its novelty and of its far-reaching significance. Many ambiguities in his exposition here and elsewhere would then have been obviated.[128]
The unconditioned which Reason postulates in all things by themselves, by necessity and by right.[129]—Points are here raised the discussion of which must be deferred. Cf. below, pp. 429-31, 433-4, 558-61.
The Critique is a treatise on method, not a system of the science itself.[130]—Cf. A xv.; B xxxvi.; and especially A 11 = B 24, below pp. 71-2.
The Copernican hypothesis.[131]—Kant’s comparison of his new hypothesis to that of Copernicus has generally been misunderstood. The reader very naturally conceives the Copernican revolution in terms of its main ultimate consequence, the reduction of the earth from its proud position of central pre-eminence. But that does not bear the least analogy to the intended consequences of the Critical philosophy. The direct opposite is indeed true. Kant’s hypothesis is inspired by the avowed purpose of neutralising the naturalistic implications of the Copernican astronomy. His aim is nothing less than the firm establishment of what may perhaps be described as a Ptolemaic, anthropocentric metaphysics. Such naturalistic philosophy as that of Hume may perhaps be described as Copernican, but the Critical philosophy, as humanistic, has genuine kinship with the Greek standpoint.
Even some of Kant’s best commentators have interpreted the analogy in the above manner.[132] It is so interpreted by T. H. Green[133] and by J. Hutchison Stirling.[134] Caird in his Critical Philosophy of Kant makes not the least mention of the analogy, probably for the reason that while reading it in the same fashion as Green, he recognised the inappropriateness of the comparison as thus taken. The analogy is stated in typically ambiguous fashion by Lange[135] and by Höffding.[136] S. Alexander, while very forcibly insisting upon the Ptolemaic character of the Kantian philosophy, also endorses this interpretation in the following terms:
“It is very ironical that Kant himself signalised the revolution which he believed himself to be effecting as a Copernican revolution. But there is nothing Copernican in it except that he believed it to be a revolution. If every change is Copernican which reverses the order of the terms with which it deals, which declares A to depend on B when B had before been declared to depend on A, then Kant—who believed that he had reversed the order of dependence of mind and things—was right in saying that he effected a Copernican revolution. But he was not right in any other sense. For his revolution, so far as it was one, was accurately anti-Copernican.”[137]