Immanuel Kant (1724-1804)

1
Immanuel Kant(1724-1804)

• The Critique of Pure Reason
• (1781, 1787)

(Text, pp. 157-213)
2
(No Transcript)
3
Topics covered in the reading

• The nature, scope, limits of human knowledge
  (pp. 157-183)
• 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 (pp. 184-195)
• Morality metaphysics freedom, immortality,
  God (pp. 196-213)

4
What is knowledge?
Introductory Note

• Answer Knowledge is verified true belief.
• To know is to believe
• the belief must be true (rather than false) and
• the belief must be verified, i.e., proved true.

5
According to Kant,
The Rationalist-Empiricist Dispute

• 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

8
A priori judgments are necessarily universally
true (or false), whereas

• a posteriori 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
Its 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., 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
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

• 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
that there are

• synthetic a priori judgments

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

• 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?

25
Kants solution of
the general problem of pure reason

• How are synthetic a priori judgments possible?

26
Kants 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
Kants overall view
Transcendental Ideas Moral Postulates
(Rational Belief)
Noumena
Reason (Vernunft)
Objects of Consciousness
Understanding (Verstand)
Categories
Phenomena
Sensibility (Sinnlichkeit)
Mind
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
from knowledge to

• rational belief

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 reasons
  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 Cosmosenables 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 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 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
Kants 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,

• 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
According to Kant,
Freedom of the Will

• 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. 201 in text), he seeks to deduce
  the moral law from the concept of moral duty (or
  obligation).

56
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.

(Text, p. 208)
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.