Critique of Pure Reason

1. Critique of Pure Reason Philosophy 1 Spring, 2002 G. J. Mattey

2. Gottfried Willhelm Leibniz • Born 1646 • From Germany • Invented calculus • Had controversies with Newton • Ridiculed by Voltaire • Died 1716

3. The Leibniz-Wolff Philosophy • Leibniz’s views were modified by the German philosopher Christian Wolff • Kant worked within this framework in his “pre-critical” years • There are two principles governing metaphysics • Non-contradiction establishes what is possible • Sufficient reason establishes what exists • Both operate on the basis of pure reason

4. Immanuel Kant • Born 1724 • Prussian, of Scottish ancestry • University Professor at Königsberg • Banned from writing on religion • Died 1804

5. Kant’s Contributions • Wrote extensively on the physical and human sciences • Proposed the currently-accepted explanation of the origin of the solar system (“nebular hypothesis”) • Founder of modern geography • Tried to reconcile rationalism and skepticism • Proposed an ethical theory based on pure reason • Proposed a formalistic aesthetic theory

6. The Secure Path of Science • Many scientific endeavors are mere groping • Logic has traveled on a secure path • Its sole subject is the formal rules of all thought, no matter what it is about • As such, it is only preparatory for all the other sciences • Mathematics and physics are other secure sciences

7. A Priori Cognition • Thinking of objects, directly or through concepts, is called “cognition” • “Cognitions” are intuitions of objects or concepts of objects • Theoretical cognition concerns the relation of objects and concepts • Practical cognition concerns making the object actually exist • Theoretical cognition a priori relates objects and concepts through the use of thought alone

8. Revolution in Mathematics • Mathematics became a secure science through a revolution in thought • Mathematicians were merely groping when they tried to find the properties of figures in the figure itself • Mathematics became a science when it was seen that we know the properties of figures through construction • We “think the properties into” figures a priori

9. Revolution in Natural Science • Natural scientists were merely groping when they tried to discover the properties of objects through mere observation • Galileo and others showed that we must investigate nature by experiment • This requires that reason actively brings its conceptions to nature and tests them out

10. Metaphysics • Metaphysics is cognition of objects through concepts alone • For example, we seek to establish the existence of God from the concept of a most real being • It is not yet on the secure path of science • Instead, it has engendered endless dispute • Should we continue the search or give up our confidence in reason?

11. Revolution in Metaphysics • Metaphysics has produced concepts in the hope that they will conform to objects • We can reverse the field and hypothesize that objects conform to concepts • This reversal is like that of Copernicus • Concepts that are generated a priori can then apply to objects necessarily • “All we cognize a priori about things is what we ourselves put into them”

12. Limitations of Metaphysics • If the revolution in metaphysics is successful, it will limit the field of metaphysics • The results of metaphysics will only apply to those objects that must conform to our concepts • These objects will be called appearances • The actual thing in itself is not cognized • This leaves an opening to fulfill our practical concerns about what we ought to do

13. An Example: Freedom and Necessity • Metaphysics establishes that appearances are mechanically determined • If appearances are things in themselves, then freedom would be impossible • But if they are not, there is a possibility of freedom • I cannot cognize freedom, but I can think it • Freedom is required for morality, so the limitation of metaphysics is required for morality

14. Metaphysics and Public Interest • What is lost to metaphysics is of interest only to scholars • Philosophical “proofs” of God’s existence, of freedom and of immortality do not influence ordinary people • We believe in these things for other reasons • God: the order, beauty, etc., of the universe • Freedom: the opposition of duty and inclination • Immortality: dissatisfaction with a limited life

15. Critique • Reason seeks to establish its own limits • Critique can cut off the roots of dangerous thinking • Materialism • Fatalism • Atheism • Lack of faith • Fanaticism • Superstition • Idealism • Skepticism

16. Composite Cognition • Cognition begins with experience • But it does not therefore arise from experience • Cognition has two components • An a priori contribution of our cognitive power (form) • An a posteriori contribution from the senses (matter)

17. A Priori Judgments • An a priori judgment has two characteristics • Strict universality (no exceptions at all) • Necessity (we cannot think it without recognizing that it must be true) • Mathematical judgments are a priori • The common judgment that all change has a cause is a priori • So Hume’s account of causal reasoning in terms of custom is incorrect

18. A Priori Concepts • Suppose you omit from an experiential concept everything that is derived from experience • Space remains from the concept of body • Substance remains from the concept of an object in general • What is left over after all omission is derived from the cognitive power

19. Analytic Judgments • Analytic judgments are the result of the clarification of our concepts • What is thought in the predicate of the judgment is already thought in the subject • Example: all bodies are extended • Analytic judgments are all a priori

20. Synthetic Judgments • Synthetic judgments add something in the predicate not already thought in the subject • They are expansive • Example: all bodies are heavy • The concept of a body does not contain that of heaviness in it • The connection is found in experience

21. A Priori Synthetic Judgments • Can a subject and predicate be connected synthetically without appeal to experience? • Example: everything that happens has a cause • Having a cause is not analytically contained in the concept of something that happens • What is the unknown X that connects them?

22. Summary Classification • Presentation • Sensation (presents only the modification of the subject) • Cognition (presents an object) • Intuition (presents a single directly object) • Concept (presents objects indirectly, through characteristics that may be common to many) • Judgment (connects concepts to other concepts or to intuitions)

23. Pure Mathematics • Mathematical judgments are synthetic • One does not think the number 12 in thinking the sum of 7 and 5 • One does not think of the shortest distance between two points when thinking of a straight line • Mathematical judgments are a priori (strictly universal and necessary) • Then how is pure mathematics possible?

24. Pure Natural Science • General principles of natural science are synthetic • Example: the quantity of motion in the world is constant • But they are also strictly universal and necessary, and hence a priori • How is pure natural science possible?

25. Metaphysics • Some metaphysical judgments are synthetic • Example: the world must have a first beginning • These judgments are also necessary and universal, if they are true • They have been accepted dogmatically because they were thought to be analytic • But if they are supposed to apply beyond experience, they cannot be justified

26. Transcendental Philosophy • What is presented here is only a critique of the use of reason a priori • The critique is transcendental • It deals with our way of cognizing objects a priori • A system of pure reason would present synthetic a priori cognitions as a system

27. Intuition • Cognition relates to objects directly through intuition • Intuition takes place when and only when an object is given • For human beings, objects are given through a receptive faculty, sensibility • Thoughts of objects through concepts relate to them only through intuition

28. Appearance • Sensation is the effect of an object on the receptive faculty • When an intuition refers to an object through sensation it is empirical • An object of empirical intuition is appearance • Appearance has two sides • A matter, given in sensation • A form, lying in the mind a priori

29. Pure Intuition • The form of intuition is called pure intuition, since it is contributed by the mind alone • Pure intuition is separate from what the understanding thinks through concepts and what sensation contributes • Space is the form of intuition of bodies • Time is the form of all intuition • Transcendental aesthetic investigates them

30. Inner and Outer Sense • Outer sense presents objects alongside one another in space • Inner sense presents states of the mind as successive in time • What are space and time? • They might be: • Actual beings • Real relations among actual beings • Merely intuited relations among intuited objects

31. Space • Space is not an empirical concept abstracted from intuitions of bodies • We need it to think of relations of bodies • Space is an a priori intuition • The absence of space cannot be presented • Space is not a universal concept • It is a unique thing, which is prior to its parts • It is an infinite given magnitude, having its parts within itself, not having infinitely many instances

32. Geometry • Geometry yields synthetic a priori judgments • The predicate amplifies the subject • They are made independently of perception of their objects • They are strictly universal and necessary • This can only be explained by space being the form of the intuition of geometric objects • As intuition, space unites geometrical concepts • As residing in the subject, it allows this unification to take place a priori

33. Ideality • Space is the form of intuition, so it applies only to objects as appearances • It does not apply to things in themselves • Space exists only from the human point of view • So, things in space exist only from the human point of view • Space and things in it are ideal

34. Reality • The ideality of space is transcendental • Space is only an a priori condition of intuition • Space is also empirically real • Space is a form of outer intuition for all humans • Objects in space are real in human experience • The ideality of space cannot be compared with that of sensory qualities • Sensory qualities are relative to individuals

35. Time • Time is an form of intuition, just as is space • Unlike space, time has only one dimension • Parts of time presuppose a single, unified time • Time is infinite, in the sense that any time-period is a limitation of it, so that it is unlimited • There can be an a priori theory of time • Time allows the explanation of change in general and motion in particular

36. Ideality and Reality • Like space, time is transcendentally ideal • Time is the form of inner sense • It is prior to the placement of objects in time • Unlike space, time is the a priori condition for all objects • If we present an object as in space, our presentation itself is in time • Things in themselves are not temporal, but time is a condition for the reality of all appearances

37. An Objection • When I present objects as in time, my mind changes its state • Changes in state take place in time • So, my presentation of objects takes place in time • So, time is prior to the presentation of objects in time • So, time is actual

38. A Reply • It is conceded that time is actual • It is the actual form in which objects are presented as in succession • But its reality is not transcendental • It is not an object that exists outside of the act of presenting objects • The fact that my presentations follow one another does not make time something in itself

39. Space and Time • Space and time are two sources of cognition • Appearances are necessarily subject to them • Because they are forms of cognition, we can understand how we can make judgments a priori about them • If we think of them as existing in themselves, we have to explain how two non-entities can be the condition of all objects • Concepts such as motion or change require experience and are not a priori

40. Confused Presentations? • Leibniz and Wolff held that sensibility is confused presentation of things in themselves • Only the intellect yields clear presentations (of things in themselves) • But this distinction is purely logical • The distinction between sensibility and intellect concerns the nature and origin of our cognitions • Sensibility provides no presentation at all of things in themselves

41. Intellectual Intuition • Human intuition is sensible and passive • An intellectual intuition would produce its own objects (“self-actively”) • We intuit our own mind by being passively given successive mental states in time • So, we do not represent ourselves as an intellectual intuition would represent us

42. Illusion? • Does the fact that outer objects and my inner state are transcendentally ideal mean that they are illusory? • Illusion results from taking these to be transcendentally real • On that assumption, we cannot explain the nature of space and time • This is why Berkeley downgraded bodies to illusion • Even the mind itself would be illusory, since its states are in time

43. God’s Intuition • God cannot be an object of intuition to us or an object of self-intuition in space and time • If space and time were conditions for the existence of all things, they would be a condition for God’s existence • Then God could not cognize his own existence • God’s intuition must be intellectual

44. Concept and Intuition • Intuitions are the result of the passive reception of sense-impressions • Concepts are the result of the activity of the understanding • Both may be empirical or pure • Empirical cognition has sensory elements • Pure cognition is free of sensory elements • Cognition arises only from their union

45. Logic • General logic concerns rules of thought that apply to all objects that can be thought • Pure general logic concerns formal rules of thought • Applied general logic concerns the psychology of reasoning • Special logic concerns rules (of methodology) applying to thought about specific kinds of objects

46. Transcendental Logic • Some thoughts about objects are pure, others are empirical • Pure thoughts have their origin in the understanding, rather than experience • A logic of pure thoughts is transcendental • To be transcendental is to be concerned with the fact that the origin of a presentation is a priori • Transcendental logic concerns concepts that arise in the mind independently of sense-experience yet are applicable to objects

47. Truth • Truth is the agreement of a cognition with the object it is supposed to present • There is no universal criterion of truth of material (experiential) cognition of objects • There is a universal criterion of truth of formal (a priori) cognition of objects • The understanding must be in agreement with its own activities

48. Analytic and Dialectic • Analytic is the part of logic that concerns the formal rules of its use • Transcendental analytic concerns the rules governing a priori concepts • It is a logic of the truth of a priori cognition • Dialectic is the attempted use of logic to establish material truths • Transcendental dialectic concerns the misapplication of rules governing a priori concepts • It is a logic of illusion

49. Completeness • Transcendental analytic presents pure concepts derived from the understanding • The derivation of these concepts must be based on a single principle • This principle should encompass the whole of the understanding • So, it should present a complete and coherent system of pure concepts

50. Functions • The understanding operates by making judgments connecting concepts to one another or to intuitions • A function is the unity of the act of bringing many presentations under one concept • So, judgments are functions of unity of presentations (concepts or intuitions) • Concepts are functions of unity of intuitions