1. The Critique of Pure Reason (1781, 1787)
11/27/06
Immanuel Kant ( )
The Critique of Pure Reason
(1781, 1787)
(Text, pp )

2. Anthem

3. Topics covered in the reading
The nature, scope, & limits of human knowledge
a priori & a posteriori knowledge
analytic & synthetic judgments
synthetic a priori judgments & how they are possible
phenomena, noumena, & the "transcendental ideas of pure reason"
The transcendental ideas of pure reason: self, cosmos, & God
Morality & metaphysics: freedom, immortality, & God

4. Introductory Note
What is knowledge?
Answer: Knowledge is verified ("justified") true belief.
To know is to believe;
the belief must be true (rather than false); and
the belief must be verified ("justified"), i.e., proved true.

5. The Rationalist-Empiricist Dispute
According to Kant,
all knowledge begins with sense experience, but not all knowledge arises out of sense experience.

6. There are two basic types of human knowledge:
a priori knowledge, which arises from the operations of the mind & is independent of sense experience
a posteriori knowledge, which arises from & depends on sense experience; and

7. The distinguishing characteristics of pure a priori knowledge:
Necessity
and
Strict universality (no possibility of an exception)

8. A priori judgments are necessarily & universally true (or false), whereas
a posteriori (empirical) judgments are never necessarily or universally true (or false).*
*They are contingently true (or false).

9. A further Kantian distinction
Analytic Judgments
vs.
Synthetic Judgments

10. It's all about subjects & predicates

11. In an analytic judgment or proposition,
the predicate makes explicit (explicates) meanings that are already implicit in the subject (e.g., "a triangle is three-sided").

12. In a synthetic judgment or proposition,
the predicate adds to our knowledge of the subject in a way that logical analysis, by itself, cannot (e.g., "some houses are white").
The predicate of a synthetic proposition augments & amplifies our knowledge of the subject.

13. The relationships between analytic, synthetic, a priori, & a posteriori judgments

14. Analytic judgments express a priori knowledge, i. e
Analytic judgments express a priori knowledge, i.e., they are necessarily & universally true (or false),
& they can be verified or falsified independently of sense experience, i.e., by logical analysis alone.
(There is no need to test them a posteriori.)

15. "Material objects are extended in space."
This proposition is both analytic & a priori.

16. are always synthetic (e.g., "material objects have weight").
A posteriori judgments (which must be verified or falsified on the basis of sense experience, not through logical analysis)
are always synthetic
(e.g., "material objects have weight").

17. So

18. there are (uncontroversially)
analytic a priori judgments,
synthetic a posteriori judgments, and
analytic a posteriori judgments (which are a waste of time, since analytic judgments can be verified or falsified by logical analysis alone).
In addition to these, Kant claims

19. synthetic a priori judgments
that there are
synthetic a priori judgments
(This is controversial!)

20. A synthetic a priori judgment is one that is
necessarily & universally true (& thus not derived from sense experience, i.e., it is a priori)
and in which
the predicate adds something to our knowledge of the subject that could not be known merely by logical analysis of the subject.

21. Examples of synthetic a priori judgments (according to Kant)
"Everything that happens has a cause."
"7 + 5 = 12"
"A straight line is the shortest distance between two points [in space]."
"In all changes of the material world, the quantity of matter remains unchanged."
"In all communication of motion, action and reaction must always be equal."
"The world must have a beginning."

22. This leads to what Kant calls
"the general problem of pure reason"

23. How are synthetic a priori judgments possible?

24. To this general question, Kant adds several subsidiary questions:
"How is pure mathematical science possible?"
"How is pure natural science [physics] possible?"
"How is metaphysics as a natural disposition possible?"
"How is metaphysics as a science possible?"
(We will not at this time pursue answers to these questions.)

25. How are synthetic a priori judgments possible?
Kant's solution of
the general problem of pure reason
How are synthetic a priori judgments possible?

26. Kant's "Copernican Revolution in Philosophy"
The relationship between the mind & its objects
Objects ?
Mind

27. According to Kant,
the mind does not conform to its objects. On the contrary, the objects of consciousness conform to the structure & operations of the mind itself.

28. The structure of the mind
Pure
Reason
(Vernunft)
Understanding
(Verstand)
Categories
Sensibility
(Sinnlichkeit)
Categories
of the Under-
standing
Forms of
space &
time
Forms of
Sensibility

29. Kant's overall view (Rational Belief) (Vernunft) Mind (Knowledge)
Transcendental Ideas
& Moral Postulates
(Rational Belief)
Noumena
Reason
(Vernunft)
Objects of Consciousness
Understanding
(Verstand)
Categories
Phenomena
Mind
Sensibility
(Sinnlichkeit)
Forms of
space &
time
(Knowledge)

30. Categories of the Understanding
Of Quantity
Unity (Singularity)
Plurality (Particularity)
Totality (Universality)
Of Quality
Affirmation
Negation
Limitation
Of Relation
Substance-Attribute
Cause-&-Effect
Community (Interaction)
Of Modality
Possibility-Impossibility
Existence-Nonexistence
Necessity-Contingency

31. The categories of the understanding
are applicable only to phenomena that appear to us under the forms of sensibility (space & time);
they have no legitimate application to noumena, i.e., realities or alleged realities that transcend the realm of space & time.

32. However,
in an effort to construct a totally unified, coherent, & systematic world-view,
human reason (Vernunft) thinks beyond the phenomenal realm
and formulates ideas of realities (i.e., possible realities) that transcend the world of experience.

33. This takes us

34. rational belief from knowledge to
The transcendental metaphysics of Pure Reason

35. The Transcendental Ideas of Pure Reason
Self, Cosmos, & God

36. The content of the transcendental ideas

37. The Transcendental Idea of the Self
a thinking substance (soul)
simple & unchangeable
has a personal identity that persists through time
exists in relation to other real things outside it
experiencer & thinker

38. The Transcendental Idea of the Cosmos (or world-in-general)
a unified and infinitely long series of events
the totality of all causal series

39. The Transcendental Idea of God
The primordial, single, self-subsistent, all-sufficient, supreme ground of being
Supreme creative & purposive reason as the cause of the universe 

40. The Justification of the Transcendental Ideas
They are the foundations for reason's construction & account of the systematic unity of experience.

41. The Idea of the Self enables reason to construe
all of "my" subjective experiences as existing in a single subject (my "self"),
all of "my" powers of perception & thought as derived from a single source (my "self"),
all changes within "me" as belonging to the states of one & the same permanent being (my "self"), and
all phenomena in space as entirely different from the activity of thought (i.e., as other than my "self").

42. In other words, the idea of the Self
provides me with a metaphysical foundation for the unity of my experience.

43. The Idea of the Cosmos enables reason to
think of the world as if it were a unified collection or totality of infinitely long causal series that can be endlessly investigated by science.
In other words, the idea of the cosmos-as-a-whole is a stimulus to scientific inquiry.

44. The Idea of God enables reason to see nature
as a system grounded in reason
and
pervaded with purpose
since God is Supreme Reason
aiming at
the ultimate good of all things.

45. In other words,
the idea that God (a supremely rational & purposive being) is the cause (creator) of the universe
enables us to see the world as a teleological unity
in which everything (absolutely every-thing) serves some purpose.

46. Kant seems to be saying that,
unless we assume the existence of the Self (transcendental ego), the Cosmos-as-a-whole, & God,
the world & our experience of the world
will lack systematic unity & coherence.
In other words, the world & our experience of the world cannot be completely intelligible (or meaningful) without the transcendental ideas of pure reason.

47. However ,

48. the transcendental ideas
are "regulative,"
not "constitutive."
That is, they guide or "regulate" our study of the world by leading us to proceed AS IF the Self, the Cosmos-as-a-whole, & God are real.
However, the objects of the transcendental ideas (Self, Cosmos, & God) do not "constitute" actual objects of experience; they are "merely" ideal objects, which, if real, add systematic unity & coherence to our experience of the phenomenal world.

49. But we cannot KNOW whether or not the Self, the Cosmos, & God are real
because they are "transcendental" (noumenal) objects, i.e., they are not phenomena that appear in space & time
& to which the categories of the understanding can be applied.

50. Morality, Happiness, & Metaphysics
Freedom, Immortality, & God
(The Postulates of Practical Reason)

51. Kant's distinction between
theoretical reason (reasoning about the universe, the world of nature)
and
practical reason (reasoning about human existence & action)

52. As we have seen, Similarly . . . ,
pure reason (i.e., pure theoretical reason), in seeking to understand the universe as a whole, formulates certain "transcendental ideas"
(of Self, Cosmos, & God).
Similarly ,

53. pure practical reason,
in an effort to see human existence & human moral effort as meaningful,
postulates the reality of moral freedom, the immortality of the soul, & the existence of God.
(In the Critique of Practical Reason (1788), Kant calls freedom, immortality, & God "the postulates of practical reason.")

54. morality (the moral law) tells us what we OUGHT to do.
Freedom of the Will
According to Kant,
morality (the moral law)
tells us what we OUGHT to do.
Thus, morality presupposes freedom of the will
because, logically speaking, "ought" implies "can."

55. The existence & nature of the moral law
In the Critique of Pure Reason, Kant assumes the existence of pure a priori moral laws that determine what we ought and ought not do.
In his later works on ethical theory (see footnote on p. 358 in text), he seeks to deduce the moral law from the concept of moral duty (or obligation).

56. reason discerns a relationship between morality & happiness.
According to Kant,
reason discerns a relationship between morality & happiness.
What is the nature of that relationship?

57. On this subject,
there is a difference between the pragmatic law & the moral law.
The pragmatic law answers the question, "What must I do in order to become happy?"
The moral law answers the question, "What must I do in order to deserve (be worthy of) happiness?"

58. Moral laws are
categorical imperatives, i.e., absolute & unconditional moral commands (e.g., "Be honest");
they are NOT
hypothetical imperatives (e.g., "If you wish to have a good reputation, be honest").

59. In general, the moral law says,
"Do that through which you become worthy of happiness."

60. Reason is not satisfied
with morality all by itself,
nor with
happiness all by itself.
In a completely good world, "a system in which happiness is tied and proportioned to morality [which makes one worthy of happiness] would be necessary."

61. "What is the supreme good of the moral world that a pure but practical reason commands us to occupy?"
"It is happiness in exact proportion to the moral worth of the rational beings who populate that world."

62. For such an ideal world to exist, two things are necessary:
the existence of God;
and
the immortality of the soul.
Only God can guarantee the ideal proportionality of morality & happiness.
If happiness & unhappiness are to be necessary consequences of our conduct in the empirical world, then there must be a future world in which the soul lives on.

63. That’s all, folks!