1. Epistemology “Episteme” = knowledge “Logos” = words / study of
What does it mean to know something?
How do we know things?

2. Plato’s Cave

7. Theories of Knowledge

8. Epistemology “Episteme” = knowledge “Logos” = words
What does it mean to know something?
How do we know things?

9. Divisions of Theories of Knowledge

10. Rationalists
Those who believed that all knowledge can be known by the mind inquiring within itself
We are born with innate ideas
Rene Descartes

11. Empiricists
Those who believe that all knowledge is derived from experience
John Locke ( )
George Berkeley ( )
David Hume ( )

12. Rene Descartes
( )

14. All knowledge can be known through the mind inquiring within itself
Rationalist
All knowledge can be known through the mind inquiring within itself

15. Cartesian Theory of Knowledge
Meditation One
“The Method of Doubt”

16. In order to discover that which is absolutely true,
we try to find that which we absolutely cannot doubt

17. we must disregard that path to absolute truth
If we get deceived once,
we must disregard that path to absolute truth

19. Can we absolutely trust Our Senses?
Sight
Hearing
Touch
Taste
Smell

20. NO!

21. Sight?
Mirage

22. Ringing in our ears after concert
Hearing?
Ringing in our ears after concert

23. Touch?
Amputation

24. Taste?
Novocain

25. Smell?
Hallucinations

26. Sometimes they are incorrect
Our Beliefs?
No!
Sometimes they are incorrect

27. Certain we have bodies?
NO!
Matrix!

29. Can you tell that you are dreaming when you are dreaming?
Dreams?
Can you tell that you are dreaming when you are dreaming?

31. You usually realize you have been dreaming
AFTER
You wake up

32. How do you know for certain that your life is not simply a dream
And when you die
You simply wake up from this dream

33. An Evil God?
Is there anything this Evil God could not deceive you into thinking you were doing?

35. Waterskiing

36. Mountain Climbing

38. Could this Evil God deceiving you into thinking if you weren’t really thinking?

39. Wouldn’t you have to be thinking in order to be deceived?

41. “I think, therefore I am”
Cogito Ergo Sum
“I think, therefore I am”

42. Our Essence
Is Thinking

43. When we think about ourselves thinking, we cannot be deceived
Can’t be deceived
When we think about ourselves thinking, we cannot be deceived
Even by an Evil God

44. This is the only thing we can know for absolutely certain
Cogito Ergo Sum

45. Solipsism
the view that the self is all that can be known to exist.

46. Criterion of Certainty
Clear and Distinct Idea
We have a clear and distinct idea of
something it is true
Cogito ergo sum
Material Objects and Extension

47. Standard Formal (1) I think Therefore (2) I am (I exist)
Cogito ergo sum

48. Standard Formal (1) I can’t be sure about my beliefs
(2) I can’t be sure about my senses
(3) I can’t be sure about my thoughts
(4) But when I think about myself thinking, I must exist
Therefore
(5) I exist

49. Doesn’t get us very much
Problem
Doesn’t get us very much

50. In order to get to objective reality, he must prove two other things

51. 1. That God Exists

52. 2. That God is not a Deceiver

53. Descartes’ Proof for the Existence of God
Where does the idea of God come from?

54. Our idea of God is greater than we should be able to think of

55. God is:
Perfect
Infinite
Omnipotent
Omniscient
Omni-benevolent
Eternal

56. Nothing is our world possesses these qualities

57. Descartes’ Conclusion
The origin of our idea of God is God

58. That God is not a Deceiver
Deception is an imperfection
God is perfect
Therefore God is not a deceiver

60. Reality can be trusted most of the time
What does this give us?
Reality can be trusted most of the time
No 100%
But most
If we are careful

61. 4 Rules that will help us to arrive at approximate truth
Discourse on Method
4 Rules that will help us to arrive at approximate truth
Make less mistakes

62. 1. Never accept anything as true unless it is self-evident

63. Divide each problem into as many parts as possible
2. Divide and Conquer
Divide each problem into as many parts as possible

64. Then more to the more difficult
3. Begin with the Easiest
Then more to the more difficult

65. 4. Be as Complete as Possible
Omit nothing

66. Innate Ideas
Ideas we are born with

67. 1. God’s Existence

68. 2. Metaphysical Truths The Law of Non-Contradiction
Something cannot both exist and not exist at the same time

69. 3. Mathematical Truths
1 + 1 = 2