philosophy of knowledge & reality€¦ · kant’s revolutionary idea • the mind does not...

W E E K 7 : E P I S T E M O L O G Y - K A N T

PHILOSOPHY OF

KNOWLEDGE & REALITY

AGENDA

1. Review of Epistemology

2. Kant

• Kant’s Compromise

• Kant’s Copernican Revolution

3. The Nature of Truth

REVIEW:

THREE KINDS OF KNOWLEDGE

1. Knowledge by acquaintance (knowing someone/thing, familiarity)

2. Knowing how (competence, skill)

3. Propositional knowledge (know that)

• In philosophy, we are almost always concerned with #3

• So epistemology is ___________________.

REVIEW: THE MAJOR THEORIES OF

KNOWLEDGE

Knowledge is true, justified belief.So, how can we justify our belief as being true?

1. Skepticism• You can’t. • Problem with this theory?

• Global skepticism is not very practical (law, science, morality, etc..)

2. Rationalism• Through reason and logic• Problem with theory?

• Many truths are simply true by definition and do not say anything about the world.• Truth that does say something often relies on empirical evidence.

3. Empiricism• Through your sense experiences. • Problem with this theory?

• 1) Senses can be deceiving and perception is subjective, 2) no causation, 3) in general knowledge

QUICK REVIEW: EPISTEMOLOGY

Rationalist (1596 – 1650)

• Senses can’t be trusted.

• Knowledge comes from reason – (e.g. mathematics, “I think, therefore I am”.)

Empiricist (1632 – 1704)

• Mind is a blank slate.

• Solving the perc. problem: Two qualities-primary & secondary.

• Our perceptions “represent” reality.

Empiricist (1685 – 1753)

• Only experience ideas, so only ideas exist – no material world.

• Mind important: To exist is

to be perceived.

Empiricist (1711- 1776)

• Can never have general knowledge.

• Can never experience causes.

Descartes Locke

Berkeley

Hume

KANT’S EPISTEMOLOGY

Immanuel Kant (1724-1804)

German Philosopher

• Changed epistemology forever with…

• 1) Kant’s Compromise

• 2) Kant’s Copernican Revolution

KANT’S COMPROMISE

• “Yes, empiricists, there are contingent truths known by experience. But the mind does not passively take in sensory information. We are not blank slates.”

• “Yes, rationalists, there are necessary truths known through reason. But knowledge is not gained by reason alone.”

Let’s make a compromise!!

KANT’S COMPROMISE

We need to change the way we look at knowledge and say there are different types of truths.

• Distinction # 1: In addition to knowledge being

• a priori (before experience)

• a posteriori (after experience)

• Distinction # 2: Let’s make another distinction:

• Analytic = true by definition, not new info.

• Synthetic = truth beyond definition alone, provides new info

KANT’S COMPROMISE

4 CLASSIFICATIONS OF JUDGMENTS

a priori knowledge

• The shortest distance between two points is a straight line.

• The velocity of a body remains unchanged unless acted on by an outside force.

• Every event has a cause

• All bachelors are unmarried.

• All triangles have three angles.

• A red ball has color.

a posteriori knowledge

• John is under 12 ft tall.

• Mount Everest is the highest mountain on Earth

• There are more people in San Francisco than Milpitas.

Synthetic

Analytic

This comes from experience.

Where does this come from?

This comes from definition.

See! Reason does give us knowledge!

KANT’S REVOLUTIONARY IDEA

• The mind does not passively conform to its objects.

• On the contrary, the objects of consciousness conform to the inherent, a priori structures & categories of the mind itself.

• Two big ways the mind structures & categorizes reality:

time and space

KANT’S COPERNICAN REVOLUTION

1. IMPACT ON SYNTHETIC A PRIORI TRUTHS

Let’s Look at an Example “Truth”:

Every event has a cause (or even simply “causation exists”).

• Our mind understands objects as existing in time.

• This truth is true because of how the mind structures reality as existing sequentially, in the flow of time.

KANT’S COPERNICAN REVOLUTION

1. IMPACT ON SYNTHETIC A PRIORI TRUTHS

Let’s Look at an Example “Truth”:

The shortest distance between two points is a straight line.

• Our mind understands objects as existing in space.

• This truth is true because of how the mind structures reality as existing WITHIN space. (you actually can’t see straightness)

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

All sense experience is then filtered and shaped by our minds.

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

KANT’S COPERNICAN REVOLUTION:

2. IMPACT ON SYNTHETIC A POSTERIORI TRUTHS

KANT’S COPERNICAN REVOLUTION

Therefore:Our truths are never about reality. Our truths are about how our mind best makes sense of reality.

Therefore: We never know reality as it is (Noumena).We can only know it as shaped by our mind (Phenomena).

All understanding and perception of reality is filtered and shaped by our biology and mind.

NEW THEORY OF THE UNIVERSE

NEW THEORY OF THE UNIVERSE

Leonard Susskind Raphael Bousso

What?!!!

NEW THEORY OF THE UNIVERSE

Holographic Universe?https://www.youtube.com/watch?v=16WIlRJxnrY&index=30&list=PLCF863678A8B511B8

GROUP DISCUSSION

• What is “Kant’s Copernican Revolution” and why does it lead Kant to believes that we cannot know the truth about reality as it is?

• Describe how this might lead some to believe that knowledge does not exist.

KANT AND KNOWLEDGE

• Do you think Kant’s philosophy denies the existence of knowledge?

• He actually says that knowledge is possible, because knowledge is about how things appear to us, not about how things are in themselves.

• What does he mean by this?

• Without our mind to structure reality, we only have sensations, and sensation alone isn’t knowledge.

• Knowledge is how we make sense of raw sensation.

KANT AND KNOWLEDGE

• Hence: Our brain creates knowledge.

• Does this make sense if knowledge is justified, true belief. • Justified?• Belief?• True?