immanual kant
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IMMANUAL KANTIMMANUAL KANT
The Copernican Revolution in Philosophy
The Copernican Revolution in Philosophy
IMMANUAL KANTIMMANUAL KANT
IMMANUAL KANTIMMANUAL KANT
Kant was one of the first to truly appreciate Hume’s skeptical
dilemma.
IMMANUAL KANTIMMANUAL KANT
Hume had demonstrated that many of our basic common
sense beliefs cannot be justified.
IMMANUAL KANTIMMANUAL KANT
Common Sense Beliefs:1. There is an independent
physical world. (Material substance exists.)
2. I exist.
3. Every event is caused.
4. Causal laws will not change.
IMMANUAL KANTIMMANUAL KANT
Hume had shown that none of these statements are analytic truths, and none of them are a
posteriori truths.
Hume insists that every truth is either an analytic a priori truth, or a synthetic a posteriori truth.
IMMANUAL KANTIMMANUAL KANT
Hume points out that a statement can be true based on experience, or because it
is a logical truth, but NO OTHER WAY!
IMMANUAL KANTIMMANUAL KANT
But those 4 common sense beliefs could not be justified
either way.They are not based on
experience (not a posteriori)and they are not logical truths (not analytic).
IMMANUAL KANTIMMANUAL KANT
Kant agrees with Hume’s analysis of the problem, but
has a more ingenious solution than Hume. For Hume, these 4 beliefs are simply habits of mind.
IMMANUAL KANTIMMANUAL KANT
Kant’s solution requires a radical revision in our
understanding of the way knowledge of the world
comes about.
IMMANUAL KANTIMMANUAL KANT
Kant calls his solution:
THE COPERNICAN REVOLUTION IN PHILOSOPHY
THE COPERNICAN THE COPERNICAN REVOLUTION IN PHILOSOPHYREVOLUTION IN PHILOSOPHY
The original Copernican Revolution was in Astronomy.
Copernicus theorized that the Earth revolves around the sun and not the other way around
as most thought.
THE COPERNICAN THE COPERNICAN REVOLUTION IN PHILOSOPHYREVOLUTION IN PHILOSOPHY
Just as Copernicus replaced a passive Earth
with an Earth actively involved in the motion of the
heavens…
THE COPERNICAN THE COPERNICAN REVOLUTION IN PHILOSOPHYREVOLUTION IN PHILOSOPHY
Kant would replace the notion of a passive mind
with that of an active mind that actively constructs knowledge of the world.
THE COPERNICAN THE COPERNICAN REVOLUTION IN PHILOSOPHYREVOLUTION IN PHILOSOPHY
Kant saw an analogy between what Copernicus did to astronomy and what
he was about to do to philosophy.
THE COPERNICAN THE COPERNICAN REVOLUTION IN PHILOSOPHYREVOLUTION IN PHILOSOPHY
What is Kant’s solution? What does he mean by an
active mind?
Let’s look at
Kant’s Active Mind Theory of Knowledge.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
Kant realized that Hume’s skeptical argument
(sometimes called Hume’s fork) demonstrated that
neither the rationalists nor the empiricists could
account for our knowledge.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
Yet Kant insisted that we do know that:
1. There is a physical world.
2. I exist.
3. Every event is caused.
4. The causal laws will not change.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
To explain how we can know these things (despite Hume’s
argument) requires that Kant rethink the whole
picture of how knowledge is acquired.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
Both the rationalists and the empiricists must have
made some unrecognized mistaken
assumption. Kant thought he knew what that assumption was.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
We might call that mistaken and unrecognized
assumption:
The Passive Mind Theory of Knowledge
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
Both the rationalist and the empiricist shared the basic picture of how
knowledge is acquired.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
We can picture it using a cartoon.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
We need a world “out there” to be known:
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
A person to do the knowing:
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
And the knowledge itself.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
This IS the passive mind theory of knowledge.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
The only difference between the rationalists and the empiricists is about what connects our knowledge
to reality.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
For rationalists, our REASON
is able to directly grasp at the nature of reality.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
For empiricists, our senses
are able to directly grasp at the nature of reality.
Notice that KNOWLEDGE OF
REALITY
is a perfect copy of
REALITY ITSEF.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
As long as our knowledge
is a perfect copy of
REALITY ITSEF…
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
Then our knowledge is accurate.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
But …
How could we ever know that?
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
After all, we can NEVER compare the two!
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
All we ever deal with is our knowledge of reality…
Never reality itself.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
Since we can NEVER compare the two, we can never know
if our knowledge is accurate.
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
Thus we are inevitably lead to Hume’s skepticism!
The Passive Mind Theory of The Passive Mind Theory of KnowledgeKnowledge
Kant realized that what is required is a complete
rejection of
The Passive Mind Theory of Knowledge.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
So now we must try to picture Kant’s “Active Mind”
alternative.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
First, reality itself is independent of us, so it is
forever unknowable!
?
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
Kant calls reality itself,
NOUMENAL REALITY.
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Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
It is the source of the content of our knowledge.
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Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
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But the mind must add structure or form to render
the content knowable.
Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
It is the interaction of reality itself and the knowing mind
That allows the construction of our knowledge or reality.
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Kant’s Active Mind Theory Kant’s Active Mind Theory of Knowledgeof Knowledge
Kant calls reality as we know it,
PHENOMENAL REALITY.?
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
How does the Active Mind Theory answer Hume’s
argument?
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Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Hume showed that many of our beliefs about reality could not
be justified.
They were neither analytic truths of reason nor a posteriori
truths of experience.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Beliefs including:1. There is a physical world.
2. I exist.
3. Every event is caused.
4. The causal laws will not change.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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These beliefs are not based on reason alone (not analytic)
yet not based on experience (not a
posteriori).
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Although these beliefs are not analytic, they do come from
the mind, insists Kant.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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They are not derived from experience, they are
imposed ON experience.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Here is where the mind plays an ACTIVE role.
The mind ACTIVELY imposes these beliefs on reality as
structures, or RULES.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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So, the belief that there is an independent physical world “out there” is not based on
there being a physical world “out there,”
But is a rule imposed on reality by the mind!
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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And, the belief that there is an I (self or mind) doing the
experiencing of that world
is a rule imposed on reality by the mind!
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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And, the belief that
Every event is caused
is a rule imposed on reality by the mind!
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Finally, the belief that the causal laws will not change
is a rule imposed on reality by the mind!
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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All the beliefs that Hume could not justify
are rules imposed on reality by the mind!
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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These beliefs are not analyticAnd they are not a posteriori.
They are informative beliefs about reality, thus are
synthetic.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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These beliefs are not analyticAnd they are not a posteriori.
They are not BASED ON experience, but are
IMPOSED ON experience,
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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These beliefs are not analytic
And they are not a posteriori.
Thus they are a priori beliefs.
Overcoming Hume’s Overcoming Hume’s SkepticismSkepticism
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Kant’s ACTIVE MIND THEORY OF KNOWLEDGE allows for
a third kind of statement:
synthetic a priori.
Hume’s ForkHume’s Fork
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Hume’s fork allowed only analytic a priori truths
that come from the mind,
Hume’s ForkHume’s Fork
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And synthetic a posteriori truths
that come from reality itself.
Hume’s ForkHume’s Fork
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But now Kant introduces a third kind of truth
The synthetic a priori truths that reflect structures the mind imposes on reality.
Remember that Hume's fork allowed for only two
kinds of statements:
MATTERS OF FACT and
RELATIONS OF IDEAS.
Hume’s ForkHume’s Fork
Hume’s ForkHume’s Fork
MATTERS OF FACT
Contingent
Synthetic
A Posteriori
RELATIONS OF IDEAS
Necessary
Analytic
A Priori
Kant has now added a third prong to Hume’s Fork.
Hume’s ForkHume’s Fork
MATTERS OF FACT
Contingent
Synthetic
A Posteriori
RELATIONS OF IDEAS
Necessary
Analytic
A Priori
Hume’s ForkHume’s Fork
MATTERS OF FACT
Contingent
Synthetic
A Posteriori
RELATIONS OF IDEAS
Necessary
Analytic
A Priori
MIND IMPOSED RULES
Synthetic, A Priori Truths
RELATIONS OF IDEAS
Necessary
Analytic
A Priori
Kant’s ForkKant’s Fork
MATTERS OF FACT
Contingent
Synthetic
A Posteriori
MIND IMPOSED RULES
Synthetic, A Priori Truths
Is Kant right? Are some truths
really synthetic (informative) yet a priori (independent of
experience)?
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
According to Kant, the mind not
only imposes rules (structures) to make
knowledge possible, it must also impose rules to make
experience possible!
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
The rules the mind imposes to
make experience possible are:
SPACE & TIME ! ! !
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
If Kant is correct, space and time are not “out there” independent of us.
Space and time are structures the mind necessarily imposes
on reality to render it “experiencible!”
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Our common sense view of space is based on the passive
mind theory of knowledge.
We believe space is “out there” independent of us, and really
is exactly as we experience it.
SPACESPACE
Out there is space itself.
In the mind is the experience of space.
SPACESPACE
SPACESPACE
Notice that space as experienced (phenomenal space)
Is a perfect copy of reality itself (noumenal reality)
SPACESPACE
But Kant saw that Hume had shown this could not be right.
We cannot know the nature of space independent of us.
SPACESPACE
SPACESPACE
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Instead, noumenal reality is unknowable.
SPACESPACE
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But we see reality as being extended in 3 dimensions of space.
SPACESPACE
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Isn’t that because reality itself DOES extend in 3 dimensions of space? Kant says, “No!”
SPACESPACE
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If our knowledge of the 3 dimensional nature of reality came to us from reality by means of experience…
SPACESPACE
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Then our knowledge of space would be contingent, a posteriori, and synthetic.
SPACESPACE
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That would mean that we would have to allow that, even though every object we have come across so far has been spatial, one day we might find a non-spatial object.
SPACESPACE
?
Can you imagine discovering a physical object, but one that did not exist in space?
SPACESPACE
?
Of course not! To find an object is to find it SOMEWHERE!
SPACESPACE
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A non-spatial object makes no sense.
That shows, says Kant, that space is not experienced the way objects are.
SPACESPACE
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Space is a precondition FOR the experience of objects.
SPACESPACE
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Objects are necessarily spatial. Yet experience only gives contingent truth.
SPACESPACE
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So our knowledge of space reflects RULES our minds necessarily impose ON reality!
TIMETIME
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What about the nature of time?
TIMETIME
?
What about the nature of time?
TIMETIME
We tend to think about time using the passive mind theory of knowledge.
TIMETIME
Time, we think, exists independent of us.
TIMETIME
And we know about it by means of our experience of it.
TIMETIME
But Kant recognizes that Hume has shown us that if that were so:
TIMETIME
Our knowledge of time would be contingent, a posteriori, and
synthetic.
TIMETIME
Then we would have to say that, although all of the events we have experienced so far have
happened at some time,
TIMETIME
We might experience an event that occurs, but does not occur at
any time!
TIMETIME
But we cannot conceive of an event that occurs, but does not
occur at some time.
TIMETIME
So time is a precondition of experience, not derived from it.
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TIMETIME
Time, like space, is a MIND-IMPOSED RULE!
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Kant has demonstrated that space and time are really just
mind-imposed rules.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Thus the truths about space and time are synthetic a priori truths.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Consider the following truth about space:
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
The shortest distance between any two points is a straight line.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
What kind of a truth is that?
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
It is not an analytic truth, because the concept of “shortest” is not part of the meaning of “straight.”
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
It is not an a posteriori truth, because it is not based on
experience.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
This belief, too, would not fit on Hume’s Fork. But with Kant’s
idea of an Active Mind,
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
We get a new kind of truth…The SYNTHETIC A PRIORI.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Trying to understand Kant’s active mind theory is not easy.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
Perhaps an analogy would help. Instead of knowledge of reality,
lets consider knowledge of…the average grade
on quiz 2.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
To know the average grade on quiz 2, I need:
all of the individual grades.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
That is the content (raw data). That is like what reality itself
provides.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
But the individual grades alone are not enough.
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SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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That is the problem with the empiricist view. It wants reality to provide knowledge, but it only provides the content (raw
data).
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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To get the average grade, I need to impose structure
(rules) on that content.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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The rule is: add together all the grades, then divide the total by
the number of grades.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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But without content, the rule is empty. That is the problem
with rationalism.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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They want the mind to furnish knowledge, but on its own it just
provides rules.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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That is like trying to find the average grade on quiz 2 by
thinking hard about the rule.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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But without the individuals grades, it won’t work.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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Instead, I need both:The individual grades (content)
and the rule (structure).
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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And these rules will be SYNTHETIC, yet A PRIORI.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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Examples of synthetic a priori truths:1.The shortest distance between any
two points is a straight line.2.There is an independent physical
world.3.I exist.4.Every event is caused.5.The causal laws will not change.
SYNTHETIC SYNTHETIC A PRIORIA PRIORI
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So Kant’s Copernican Revolution in Philosophy overcomes Hume’s
skepticism by making synthetic a priori truths
possible.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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But notice that there is a price to be paid.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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Phenomenal reality is such that we can rely on our 4 common sense beliefs.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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After all, our minds necessarily impose those rules on it.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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But noumenal reality (reality itself) remains forever unknowable!
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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Kant has left the concept on an unknowable noumenal reality as a
challenge to all later philosophers.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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Kant’s philosophy has had an enormous influence on all later
philosophy. But Kant might not have liked all of these developments.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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For example, Kant was sure that all minds would necessarily impose the
same rules on reality (space / time / world /
self / causality / induction).
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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But some later philosophers think different minds might impose different
rules.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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That leads to a form of relativism Kant would have denied.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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But it is an interesting hypothesis. When a scientist and an artist look at a
flower, do they see the same thing?
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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Could a person’s reality depend on the language she speaks? Some think
so.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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But Kant was a strict universalist.All mind impose the same rules.
Kant’s Copernican Kant’s Copernican RevolutionRevolution
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As for the challenge of NOUMENAL REALITY, that will have to wait until
the study of Hegel.
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T H E E N DT H E E N D