Lectures on Kant's Critique of Pure Reason 2014

2014

Chapter from the Teleology of Reason

Rationalism and Empiricism were fighting each other about the Metaphysic: can we perceive the reality? If yes, how can we perceive it? John Locke and the empiricists had claimed that our knowledge get from the experience. Our mind was a 'tabula rasa' (a blank slate); then, experience has written a thousand ways on it. Rene Descartes and the idealists rejected the blank slate doctrine and posited innate ideas in the mind. They held that our innate ideas can allow us to perceive the reality. Thus, Kant established a court name " The Critique of Pure Reason " to solve the Metaphysic problem. To understand Kant's transcendental philosophy, firstly, How Kant explains the original and limitation of our perception capacity. Then, we investigate how Kant defeats the Skepticism. Firstly, a synthetic a – priori cognition is the key that we can get knowledge. Kant supposed that the world is chaos. Physical objects are in the mass pile. The world has two forms: the noumenal world, the thing-in-itself (ding an sich) which we cannot know in any pure form but only as mediated through the categories of the mind; and, the phenomena world which appears for us. We only can percept the phenomena world. How can we know the phenomena world? Kant argued that the mind is so structured and empowered. They impose interpretive onto our experience. Our mind has two parts: sensibility and understanding. These two parts become two sources that people can perceive reality. Sensibility helps us to receive impression of thing in the world. Understanding allows us to connect together these sense impressions. For Kant, sensation which owns space and time is receptivity the impressions of reality. Understanding is ability for cognition through 12 categories:

The Critical Philosophy Next we turn to the philosophy of Immanuel Kant, a watershed figure who forever altered the course of philosophical thinking in the Western tradition. Long after his thorough indoctrination into the quasi-scholastic German appreciation of the metaphysical systems of Leibniz and Wolff, Kant said, it was a careful reading of David Hume that "interrupted my dogmatic slumbers and gave my investigations in the field of speculative philosophy a quite new direction." Having appreciated the full force of such skeptical arguments, Kant supposed that the only adequate response would be a "Copernican Revolution" in philosophy, a recognition that the appearance of the external world depends in some measure upon the position and movement of its observers. This central idea became the basis for his lifelong project of developing a critical philosophy that could withstand them. Kant's aim was to move beyond the traditional dichotomy between rationalism and empiricism. The rationalists had tried to show that we can understand the world by careful use of reason; this guarantees the indubitability of our knowledge but leaves serious questions about its practical content. The empiricists, on the other hand, had argued that all of our knowledge must be firmly grounded in experience; practical content is thus secured, but it turns out that we can be certain of very little. Both approaches have failed, Kant supposed, because both are premised on the same mistaken assumption. Progress in philosophy, according to Kant, requires that we frame the epistemological problem in an entirely different way. The crucial question is not how we can bring ourselves to understand the world, but how the world comes to be understood by us. Instead of trying, by reason or experience, to make our concepts match the nature of objects, Kant held, we must allow the structure of our concepts shape our experience of objects. This is the purpose of Kant's Critique of Pure Reason (1781, 1787): to show how reason determines the conditions under which experience and knowledge are possible. Varieties of Judgment In the Prolegomena to any Future Metaphysic (1783) Kant presented the central themes of the first Critique in a somewhat different manner, starting from instances in which we do appear to have achieved knowledge and asking under what conditions each case becomes possible. So he began by carefully drawing a pair of crucial distinctions among the judgments we do actually make. The first distinction separates a priori from a posteriori judgments by reference to the origin of our knowledge of them. A priori judgments are based upon reason alone, independently of all sensory experience, and therefore apply with strict universality. A posteriori judgments, on the other hand, must be grounded upon experience and are consequently limited and uncertain in their application to specific cases. Thus, this distinction also marks the difference traditionally noted in logic between necessary and contingent truths. But Kant also made a less familiar distinction between analytic and synthetic judgments, according to the information conveyed as their content. Analytic judgments are those whose predicates are wholly contained in their subjects; since they add nothing to our concept of the subject, such judgments are purely explicative and can be deduced from the principle of non-contradiction. Synthetic judgments, on the other hand, are those whose predicates are wholly distinct from their subjects, to which they must be shown to relate because of some real connection external to the concepts themselves. Hence, synthetic judgments are genuinely informative but require justification by reference to some outside principle. Kant supposed that previous philosophers had failed to differentiate properly between these two distinctions. Both Leibniz and Hume had made just one distinction, between matters of fact based on sensory experience and the uninformative truths of pure reason. In fact, Kant held, the two distinctions are not entirely coextensive; we need at least to consider all four of their logically possible combinations: Analytic a posteriori judgments cannot arise, since there is never any need to appeal to experience in support of a purely explicative assertion. Synthetic a posteriori judgments are the relatively uncontroversial matters of fact we come to know by means of our sensory experience (though Wolff had tried to derive even these from the principle of contradiction). Analytic a priori judgments, everyone agrees, include all merely logical truths and straightforward matters of definition; they are necessarily true.

Philosophers' Imprint, 2015

It is often claimed that anti-realism is a form of transcendental idealism or that Kant is an anti-realist.1 It is also often claimed that anti-realists are committed to some form of knowability principle to the effect that all truths (or at least all truths of a certain class) are knowable and that such principles have problematic consequences.2 It is therefore natu- ral to ask whether Kant was committed to any such principle, and if he was, whether this leads him into similar difficulties. Both transcenden- tal idealism and anti-realism aim to provide a middle way between re- alism and idealism. A logical proof published by Frederic Fitch in 1963 (though first conveyed to him by Alonzo Church in 1945) appears to show that anti-realism fails in its aim because it collapses into idealism. Can a related proof show that transcendental idealism collapses in the same way? I argue that, initial appearances to the contrary, it cannot. The paper is in two parts. In the first part, I set up the problem and, in the second part, I solve it. In §1.1, I present evidence that suggests Kant is indeed committed to a knowability principle and I show that a Fitch-Church style proof can be constructed on this basis. Kant does not think that all truths whatsoever are knowable, but it can seem as though he is commit- ted to the claim that all empirical truths are knowable, and on mod- erate background assumptions this entails that no empirical truth is unknown. In §1.2, I show that with a few additional assumptions we can also prove that all a priori truths are knowable and that no a pri- ori truth is unknown. This is an interesting result with more general philosophical lessons concerning how certain classes of truth relate within a framework of knowability. But it is a little unfair to Kant. Ar- guably, we ought to further restrict our candidate Kantian knowability principle to what I call purely empirical truths, and doing so blocks the seepage into the a priori realm. However, this move would still leave Kant forced to concede that there are no unknown purely empirical truths, which is hardly more palatable. Thus in the second part of the paper I explore an alternative route. The evidence for Kantian knowability relies on interpreting Kantian experience as a form of knowledge. This is a standard view, but it is not always correct. Sometimes Kantian experience is something more like final science. In §2.1, I explain this conception of experience and apply it to the case at hand. Because, for Kant, experience so conceived is an unachievable epistemic ideal, it expresses no knowability prin- ciple to define truth in terms of it. Arguably, however, this proposal would still leave Kant committed to the claim that all purely empirical truths can be the objects of justified belief, and it has been objected that this kind of principle remains just as susceptible to Fitch-Church style reasoning.3 In §2.2, I argue that Kant has exactly the resources needed to rebut such an objection. Kant’s theory of truth has both realist and idealist aspects and is in a way anti-realist. But Fitch-Church style reasoning alone cannot show us that the theory is absurd.

Transcendental Inquiry, 2016

The aim of this paper is to set out some features of Kant's conception of transcendental philosophy. I would like to argue that this philosophy, although it is situated at a higher level of discourse than common knowledge, does not essentially transcend the limits that it sets to this knowledge. In order to achieve this, I stress the fact that Kant regards experience as a mere "possibility." Now, the Critique of Pure Reason explains that the human understanding cannot conceive of an absolute possibility, but only a relative one, namely a possibility that is tied to conditions. And possible experience as a whole is no exception here. Hence the expression "conditions of the possibility of experience" which designates the topic of the Transcendental Analytic. This also means that experience is "contingent" (A 737/B 765). It is not in itself necessary; rather, it is dependent upon certain conditions. But then we learn that the most important transcendental conditions for this experience, i.e., the dynamic principles, are themselves "contingent" (A 160/B 199). Consequently, these transcendental conditions are not unconditioned; they in turn depend on empirical conditions, over which they have no control.