Immanuel Kant’s
Epistemology
• Life
– Born in Königsberg, Prussia (now part of
Russia) in 1724.
– His family was originally from Scotland.
(The original family name was ‘Cant.’)
– The family immigrated to Prussia to avoid
religious persecution.
– Never traveled more than 60 miles from
Königsberg, and didn’t leave it at all
during a forty year stretch.
– Attended the University of
Königsberg from 1740 – 1755.
– In 1755, received his doctorate and
became a Lecturer at the University.
He was named full professor in 1770.
– Author of three of the greatest works
in the history of philosophy.
• The Critique of Pure Reason (1781)
– on Epistemology
• The Critique of Practical Reason
(1788) – on Ethics
• The Critique of Judgment (1790) –
on Aesthetics
– A man of precise habits.
• Would stroll every day, for exactly
one hour, eight times up and down
the same street.
• The street came to be called “The
Philosopher’s Walk.”
• So punctual, that the housewives of
Königsberg set their clocks by the
time he took his walk.
– Died, very sadly, totally senile, at
Königsberg in 1804.
• Response to Hume
– Given his temperament, Kant was
not the sort of man who could abide
Hume’s suggestion that humans are
emotional, not rational, beings.
– Nor could Kant abide Hume’s claim
that, at best, science and philosophy
are games people play to have fun,
rather than ways of attaining truth.
– Still, in a sense, Kant gave Hume the
credit for all he accomplished:
• “I openly confess my recollection of
David Hume was the very thing
which many years ago first
interrupted my dogmatic slumber
and gave my investigations in the
field of speculative philosophy a
quite new direction.”
Immanuel Kant, Prolegomena to any
Future Metaphysics (1783)
– Hume had reasoned that, since it is
neither a Relation of Ideas nor a
Matter of Fact, the Principle of
Universal Causation (PUC) is,
philosophically speaking, bogus.
– Kant conceded that PUC is neither a
Relation of Ideas nor a Matter of Fact.
– Kant insisted, however, that this does
NOT mean that PUC is
philosophically bogus.
• Kant’s Analysis of Perception
– Every perception is a two-fold reality:
i.) raw sense data and ii.) the
organizing and structuring of that data
by the mind.
– Sense data, in and of itself, is a
meaningless jumble.
– Sense data makes sense only after it
has been organized and structured by
the mind’s categories.
– Category: A built in, “hard-wired”
capacity of the human mind by which
it organizes and structures raw sense
data. One of the categories is PUC.
– One may see a similarity between
Kant’s view of perception and
Aristotle’s view of substance.
– For Aristotle, a substance is created
when a form organizes and structures
inherently formless and structureless
prime matter.
– For Kant, a perception is created
when the mind’s categories organize
and structure raw and meaningless
sense data.
– An Analogy:
• Suppose you had a massive heap
of coins of different types that were
all mixed up.
• While they remain in the heap, all
mixed up, the coins really have no
value.
• You cannot go to the store and buy
something with a massive, mixed up
heap of coins.
• Before you can spend the coins, you
have to sort them with a coin sorter.
• The coins don’t really have any true
value until they are sorted by the coin
sorter.
• In this analogy, raw sense data is like
the massive, mixed up heap of coins.
• In itself, raw sense data is
meaningless jumble.
• The coin sorter is analogous to
the mind’s categories.
• The coin sorter provides
organization and structure and,
thereby, value to the massive,
mixed up heap of coins.
• The mind’s categories provide
organization and structure and,
thereby, meaning to jumbled up,
raw sense data.
• How does Kant’s analysis of perception
show that PUC is not philosophically
bogus?
– “[PUC] is neither a generalization
from experience [a Matter of Fact] nor
an analytic truth [a Relation of Ideas],
but, rather, a rule for ‘setting up’ our
world . . . . Like a rule in chess, [PUC]
is not a move within the game but one
of the rules that defines the game . . .
. So too, for our belief in the ‘external’
or material world . . . .
– “Our experience alone will not tell us
whether we are dreaming or not, and
the idea of the material (‘external’)
world is not a [Relation of Ideas] . . . .
[The material world] too is one of the
rules that we use to constitute our
experience, namely, that we shall
always interpret our experience of
[sensible] objects [as being] in space,
external to us, and material.”
Robert C. Solomon, Introducing Philosophy,
p. 215
– PUC and the other categories are, as
it were, the “laws of experience.”
– They are not true; rather, they make
empirical truth claims possible.
– Asking why the mind organizes raw
sense data by PUC, or by any of the
other categories, is exactly as silly as
asking why a criminal is put in jail.
– The answer, in both cases, is the
same: “That’s the law.”
• Kant’s Two Worlds
– A consequence of Kant’s analysis of
perception is that there are really two
worlds: The Noumenal World and the
Phenomenal World.
– Noumenal World
• The world of “things in themselves.”
• This the the world from which raw
sense data originates.
• Human beings do not live in this
world and have no knowledge of it.
– The Phenomenal World
• The world of perception.
• The world of sense data after it
has been organized and
structured by the mind’s
categories.
• This is the world in which
humans live and of which they
have knowledge.
– “[W]e indeed, rightly considering
objects of sense as mere
appearances, confess, thereby, that
[the appearances] are based upon a
thing in itself, though we know not this
thing as it is in itself, but only know its
appearances, namely, the way in
which our senses are affected by this
unknown something.”
Immanuel Kant, Prolegomena to Any Future
Metaphysics
• Kant’s “Copernican Revolution” in
Epistemology
– Humans can have no knowledge of
“things in themselves.”
– Order and structure, at least the order
and structure of humans, do not exist “out
there” in the noumenal world.
– (For all humans know, the noumenal
world might as well be Heraclitus’
formless flux.)
– Order and structure, at least those of
humans, exist “in here,” i.e. in the
phenomenal world of the human mind.
• Two Very Important Questions:
– Can we be sure that each human mind
organizes and structures the raw sense
data of the noumenal world in the same
way, by means of the same categories?
– Since the noumenal world might as well
be Heraclitus’ formless flux, isn’t it
possible that, à la the ancient Protagorian
relativists, each human being projects a
different order and structure on the
noumenal world, thereby creating his/her
own individual and unique phenomenal
world?
– By means of what he called a
“Transcendental Deduction,” Kant
attempted to argue, in The
Critique of Pure Reason, that the
answers to these questions are
respectively “Yes” and “No.”
– To challenge Kant, an episode of
Star Trek: The Next Generation
• The consensus among philosophers is
that Kant’s “Transcendental Deduction”
failed.
• At this point, therefore, we must
concede that the Protagorians could
have been right all those thousands of
years ago. It’s possible that each
human being lives in his/her own world,
a world of his/her own making.