PHILOSOPHY OF KNOWLEDGE & REALITY W E E K 7 : E P I S T E M O L O G Y - K A N T

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1 PHILOSOPHY OF KNOWLEDGE & REALITY W E E K 7 : E P I S T E M O L O G Y - K A N T

2 AGENDA 1. Review of Epistemology 2. Kant Kant s Compromise Kant s Copernican Revolution 3. The Nature of Truth

3 KNOWLEDGE: THREE KINDS 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.

4 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, 2) subjectivity, 3) can t trust majority experience

5 EPISTEMOLOGY: QUICK REVIEW Rationalist ( ) Empiricist ( ) Senses can t be trusted. Mind is a blank slate. Knowledge comes from reason (e.g. mathematics, I think, therefore I am.) Descartes Solving the perc. problem: Two qualitiesprimary & secondary. Our perceptions represent reality. Locke Empiricist ( ) Only experience ideas, so only ideas exist no material world. Mind important: To exist is to be perceived. Berkeley Empiricist ( ) Can never have general knowledge. Can never experience causes. Hume

6 KANT S COMPROMISE We need to change the way we look at knowledge and say there are different types of truths. In addition to knowledge being a priori and a posteriori, let s make another distinction: Analytic = true by definition, not new info. Synthetic = truth beyond definition alone, provides new info

7 KANT S COMPROMISE 4 CLASSIFICATIONS OF JUDGMENTS Synthetic Analytic 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 All humans are under 12 ft tall. Mount Everest is the highest mountain on Earth There are more people in San Francisco than Milpitas. This comes from experience. Where does this come from? This comes from definition.

8 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 reality: time and space 9

9 KANT S COPERNICAN REVOLUTION IMPACT ON SYNTHETIC A PRIORI TRUTHS 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.

10 KANT S COPERNICAN REVOLUTION IMPACT ON SYNTHETIC A PRIORI TRUTHS 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)

11 KANT S COPERNICAN REVOLUTION Synthetic 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 Descartes: I think therefore I am. Synthetic a Posteriori Knowledge There are two doors in this room. Our class is comprised of both men and women. I received an A on my midterm. The Revolutionary Idea: The mind is not a passive agent of experience. ALL sensory experience is based on active processing of the mind (Hume on the right track). AND ALL synthetic, a priori knowledge is true because it is imposed on reality by our mind How our mind best makes sense of its experience.

12 KANT S COPERNICAN REVOLUTION: IMPACT ON SYNTHETIC A POSTERIORI TRUTHS All sense experience is then filtered and shaped by our minds.

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25 KANT S COPERNICAN REVOLUTION All understanding and perception of reality is filtered and shaped by our biology and mind. 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).

26 GROUP DISCUSSION Synthetic 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 Descartes: I think therefore I am. Synthetic a Posteriori Knowledge There are two doors in this room. Our class is comprised of both men and women. I received an A on my midterm. Kant believes that we cannot know the truth about reality as it is, why not? What justifications would Kant give for denying the absolute reality of the synthetic a priori and a posteriori truths like these?

27 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.

28 KANT AND KNOWLEDGE Hence: Our brain creates knowledge. Does this make sense if knowledge is justified, true belief. Justified? Belief? True?

29 SO WHAT IS TRUTH? Correspondence Theory of Truth: A belief is true if and only if, it corresponds with something that exist in the world (common understanding of truth). Example: My belief that a table is in the room is true, if and only if there actually is a table in the room. Objections?: Kant has a problem with the idea that there is actually a table in the room.

30 SO WHAT IS TRUTH? Coherence Theory of Truth: A belief is true if it coheres with a body of other statements that we take to be true (fits within our web of beliefs). Example: My belief that a table is in the room is true if it coheres with other beliefs I take to be true. What beliefs does must this fit into. A room is a space that can be occupied. To be in a room means to exist in that space. A table is a piece of furniture with a flat top and one or more legs, providing a level surface on which objects may be placed. This is a room. I sense a table that occupies space in this room. Objections? Could just be fitting into a web of false beliefs: racist, psychotic, an ancient scientist (earth is flat).

31 SO WHAT IS TRUTH? Pragmatic Theories of Truth: Americans to the Rescue! Let s take a step back for a second. What is the point of finding the truth?

32 SO WHAT IS TRUTH? Pragmatic Theories of Truth: Americans to the Rescue! Charles S. Pierce ( ) Truth is tentative, dependent upon further scientific inquiry. John Dewey ( ) Truth is what works. F = MA because it works. William James ( ) Truth is useful to believe, has practical value in our lives.

33 SO WHAT IS TRUTH? Pragmatic Theories of Truth: Americans to the Rescue! In response to Correspondence Theory: Truth is tentative and always in need of re-evaluation. In response to Coherence Theory: We can t objectively know reality anyway, so let s just settle on truth as being statements of belief that is practical and works.