Kant's Critique of Pure Reason - The Aesthetic and Analytic

A convoluted and superficial overview of the first two major sections of Kant's seminal 1781 work, The Critique of Pure Reason. This deck delivers a gloss on The Aesthetic and The Analytic portions of the Critique - or the positive side of Kant's epistemology. The Dialectic is of course the final section of the work and contains Kant's negative assessment of human knowledge in which he circumscribes the legitimate scope of metaphysics.

Transcript

1. Immanuel Kant’s Critique of Pure Reason The Aesthetic and the Analytic
2. Kant’s Milieu • End of the Enlightenment – Kant’s work is both a culmination and a bridge to the next century and Romanticism. • His most celebrated work, The Critique of Pure Reason, published 1781, remains influential and much discussed today. • He attempted a synthesis or compromise between competing theories of knowledge, or epistemologies, and represents a radical reimaging of the way humans acquire knowledge. • Period of ongoing scientific discovery.
3. A cluster of related problems French Philosophes, German Aufklärer and Scottish Enlightenment philosophers grappled with questions related to the certainty of human knowledge, the status of religious dogma, ecclesiastical authority and the legitimate forms of political order. Widespread eagerness to subject longstanding conventions and received wisdom to critical scrutiny, especially sacrosanct assumptions – “écrasez l'infâme” – crush the infamous. A rift between two schools of epistemology: rationalism and empiricism. Disagreement about fundamental faculties of human reason.
4. Kant’s goals • To salvage scientific inquiry, method and knowledge from skeptical assaults. • To defend the achievements of Isaac Newton’s Principia (1687). • To portray nature as predictable and systematic while preserving a space for human freedom and moral responsibility. • To answer the challenge issued by David Hume in A Treatise on Human Nature (1738) and An Enquiry Concerning Human Understanding (1748). • To affirm the legitimacy of religious – metaphysical – investigation while also delineating its scope. • If reason cannot prove religious propositions, it cannot disprove them.
5. “I have therefore found it necessary to deny knowledge, in order to make room for faith.” Bxxx
6. A few preliminaries Empiricism: Locke and Hume – our senses are the only source of our knowledge. We cannot obtain or expand our understanding through purely abstract reflection. Rationalism: Descartes and Leibniz – abstract reflection can expand our understanding, building upon experience or reaching reliable judgments entirely independently of sense input.
7. A few preliminaries - terms A priori: Before experience. Knowledge acquired without the aid of sense input. A posteriori: Knowledge gained after experience and dependent upon sensory data.
8. Hume’s challenge • A denial of inductive inference – a cornerstone of scientific method. • A strict empiricist: • All knowledge divided into two types: • Matters of fact: obtained empirically. Expands our knowledge. • Relations of ideas – reached through logical reflection on the necessary consequences of our ideas. Merely clarifies our knowledge. This includes mathematics. • Necessary causal relationships impossible to detect from the content of experience. • Just because we witness one effect resulting from an event doesn’t mean that we can infer a universal necessity or predict future encounters.
9. “Constant conjunction”
10. Hume’s challenge Hume concludes that religious speculation reached through pure abstract reflection cannot prove matters of fact, such as the existence of god, the immortal soul, etc. All works of theology not dependent upon empirical observation must be “committed to the flames.”
11. Problems with rationalism • Clarke and Leibniz correspondence (1715-1716) reveals tensions between rationalism and Newtonian physics. • Leibniz’s rationalism: axioms reached independently of and not justified by experience: • Principle of sufficient reason • Law of non-contradiction • Identity of indiscernibles •Clarke, Newton’s proxy, argues theories of spacetime with Leibniz. •Newton defends an absolute space, Leibnitz necessarily committed to a relative spacetime.
12. Kant’s solution – Copernican revolution • Previous theories of knowledge maintained that human understanding conforms to the object. We passively receive stimuli (empiricism) or logically infer the true nature of external objects (rationalism). • Kant inverts the equation – objects conform to the mode of human understanding. • He does this to ensure the regularity of experience, safeguard the legitimacy of causality and implicate the excesses of transcendent metaphysics.
13. The architectonic of the Critique The Aesthetic – Sensibility (experience) The Analytic – Understanding (judgment) The Dialectic – Reason (metaphysics)
14. Opening arguments • Kant begins by arguing that Hume’s narrow empiricism cannot account for a type of knowledge Hume admits as valid: geometry. • To illustrate the deficiency, he introduces a new distinction: Synthetic judgments
15. Synthetic a priori knowledge • Unlike analytic judgments that “unpack” the predicates logically entailed by the terms in question, synthetic judgments expand our knowledge by adding predicates not contained in the subjects. • E.g.: • Analytic: All bachelors are unmarried men. • Synthetic: John is an unmarried man. •Synthetic a priori judgments are reached prior to encountering the objects in question in experience and without relying upon the mere unpacking of the subjects.
16. Synthetic a priori knowledge • Kant argues against Hume’s position that the axioms of mathematics and geometry in particular are justified through analytic judgments. • E.g., how do we arrive at the judgment that the shortest distance between any two points is a direct line when nothing about the concepts involved entail the idea of a straight line? • If geometry is synthetic a priori, and Hume concedes the validity of geometry, then perhaps there are other forms of synthetic a priori knowledge. • This is the approach he takes to securing the status of causality and mapping the legitimate limits of human understanding.
17. The Aesthetic • The forms of intuition: • Kant argues that geometry is possible because of the inherent structure of our sense faculties. • Raw experience would be incomprehensible if it simply reached our judging faculties disordered, in “manifold” disarray. • Kant explores the necessary conditions of experience to uncover the ordering properties of human cognition to argue for consistent, predictable rules accounting for synthetic a priori knowledge.
18. Forms of intuition Space: a condition of experience, not a feature of reality discovered by experience. Not absolute, not relative. A priori and intuitive. Time: a condition of experience, not a quality detectable in experience. A priori and intuitive.
19. Forms of intuition • Human cognition contributes the filters of space and time to raw experience. Objects therefore must conform to humankind’s mode of understanding. • That all experience must conform to space and time explains why we can project the logical implications of space and time – geometry – ahead of us into situations not yet encountered to arrive at valid synthetic a priori judgments. • Objects cannot be known apart from space and time. Therefore we cannot know objects apart from the way they appear to us in experience.
20. The Analytic – the metaphysical deduction Kant argues that human understanding does more to logically structure experience and enable knowledge than just contribute the forms of intuition. Humans are discursive beings: our knowledge consists in making judgments about things – objects, events, etc. He evaluates the types of judgments we routinely make to determine the necessary conditions underlying each. Kant derives from 12 types of judgements 12 categories, or logical concepts applied by the understanding to particular experiences.
21. The Analytic
22. The categories in action • One example (Second Analogy from Experience). • Kant’s reply to Hume’s arguments against inductive inference. • How can we perceive causal connections through experiences?
23. The Second Analogy from Experience How do we perceive an objective sequence of successive events rather than a merely subjective or arbitrary sequence of events? If I scan a house, I look arbitrarily from one wall to another, to the roof to the foundation. My subjective decisions alter the sequence, and I could reverse the order. But in order to objectively perceive a sequence of events occurring independently of my actions, there must be a rule according to which one perception follows necessarily from another, and this rule is the concept of causality.
24. Transcendental idealism Transcendentally ideal – Knowledge of objects obtained through experience is always conditioned by pure concepts of the understanding, which are a priori. Empirically real – Experience is objective and reliable because it must necessarily conforms to the forms of intuition and the concepts. Science is possible, causal judgments dependable.
25. “Without sensibility no object would be given to us, without understanding no object would be thought. Thoughts without content are empty, intuitions without concepts are blind.” B75
26. Knowledge = Intuition + Concepts
27. Pause to reflect • Kant has made concessions to both the rationalists and the empiricists. • In arguing for innate concepts of pure reason, he argues against the empiricists in support of the rationalists. • In limiting their ability to supply knowledge to experience alone, he argues against rationalists in support of empiricists.
28. Epilogue: The Dialectic – the limits of reason • Because knowledge is comprised of intuition and concepts, humans cannot acquire knowledge lying beyond experience. • But reason compels humankind to expand and refine its knowledge, to better order it. • Metaphysics is unavoidable – reason pursues understanding even beyond its experience, but this never constitutes knowledge. • Reason’s unjustified application embroils humankind in insolvable dilemmas or antinomies.
29. An eventual resolution, of sorts • Only practical reason, not speculative reason, can supply assurances of God, free will and the immortality of the soul.
30. Questions • What does this mean for our knowledge of things? Does Kant’s epistemology strengthen or weaken our understanding of the world? • Does the modern scientific consensus on the nature of spacetime jeopardize Kant’s arguments for the a priority of space and time? • Does Kant say that the external world and objects only exist in our heads?