Summary
Highlights
The lecture addresses the complicated concept of pure intuition. Kant suggests a two-stage process: first, the mind is affected, creating spatial perceptions without sensory content (pure intuitions). These pure intuitions are then organized, forming physical objects, which in turn affect the empirical mind to produce sensations. The speaker views this as a problematic and incoherent position, though Kant emphasizes its importance for explaining knowledge.
The speaker corrects a previous lecture's mistake, clarifying a reference to Jonathan Cohen instead of Jonathan Bennett. He then warns that this lecture will be particularly challenging, focusing on the deepest aspects of Kant's Critique of Pure Reason. A quick review of Lecture 5's key points includes: the 'I think' attaching to all representations, the universal and normative nature of concepts as rules, synthesis as the unifying activity of the mind, and categories as the rules for this synthesis.
Synthesis is defined as 'rule-governed reproduction in imagination of a manifold of sensibility.' Kant introduces the three-fold synthesis: apprehension of representations in intuition, their reproduction in imagination, and their recognition in a concept. These three subjective sources are crucial for understanding and experience.
The discussion moves to the synthesis of apprehension in intuition, emphasizing the pivotal role of time. Initially, Kant focused on space in earlier works, but here, time becomes fundamental. The mind is first affected, producing spatially organized perceptions without temporal order. The mind then affects itself, imposing a temporal organization on these perceptions. This means self-knowledge is not privileged but known through appearances, like other objects.
The second synthesis, reproduction in imagination, involves remembering and calling perceptions to mind in a rule-determined sequence. Kant's assertion that appearances must be subject to rules for empirical imagination to function is compared to the weak anthropic principle in physics. He argues that the underlying order of the experienced world is a priori necessary for the development of subjective habits of association and, ultimately, for conscious unity.
The third synthesis, recognition in a concept, involves identifying the rule applied during reproduction. The speaker illustrates this with an example of counting, highlighting the necessity of consciously applying and remembering the rule to achieve a unified understanding. This process allows the mind to recognize the unity of synthesis and form concepts like 'number'.
Kant abruptly shifts to define 'an object of representations.' He states that appearances are sensible representations and not objects existing outside our power of representation. This raises the problem of how we can know objects if we only have access to perceptions. The speaker reveals Kant's eventual, sophisticated answer: physical objects are structures of judgments, illustrating this with an anecdote about his former professor C.I. Lewis.
Kant claims that the thoroughgoing synthetic unity of perceptions forms the basis of experience and is nothing less than the synthetic unity of appearances in accordance with concepts. This means the universe's causal structure, as described by Newtonian physics, is an objective consequence of the subjective unity of consciousness. Kant states that the order and regularity in nature are introduced by our minds; the understanding is the source of the laws of nature and its formal unity. This is the most controversial and astonishing claim in the Critique.
A significant problem arises: if the individual mind is the lawgiver of nature, how can there be multiple, independent unities of consciousness? If 'you' are merely an appearance in 'my' consciousness, this undermines Kant's ethical theory, which presupposes moral obligations to other persons (other synthesizing egos). The speaker briefly touches on Hegel's concept of a 'world spirit' as an attempt to address this issue and concludes by outlining the topics for the next lectures.