From a class discussion about Pascal's philosophy of religion.

1. philosophy of religion
Pascal’s wager
philosophy of religion – p. 1

2. Pascal and decision theory
philosophy of religion – p. 2

3. Pascal and decision theory
Blaise Pascal (1623–1662)
philosophy of religion – p. 2

4. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
philosophy of religion – p. 2

5. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
How do we decide when the outcomes are
uncertain?
philosophy of religion – p. 2

6. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
How do we decide when the outcomes are
uncertain?
Decision theory:
philosophy of religion – p. 2

7. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
How do we decide when the outcomes are
uncertain?
Decision theory:
Rational agents seek to maximize the return on
their investment.
philosophy of religion – p. 2

8. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
How do we decide when the outcomes are
uncertain?
Decision theory:
Rational agents seek to maximize the return on
their investment.
Rational decisions are possible if we know the
possible outcomes and the probabilities of those
outcomes.
philosophy of religion – p. 2

9. Pascal and decision theory
Blaise Pascal (1623–1662)
“We are all forced to gamble . . . ”
How do we decide when the outcomes are
uncertain?
Decision theory:
Rational agents seek to maximize the return on
their investment.
Rational decisions are possible if we know the
possible outcomes and the probabilities of those
outcomes.
Can these ideas be applied to religious belief?
philosophy of religion – p. 2

10. :
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philosophy of religion – p. 3

11. a lottery
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:
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

12. a lottery
:
:
:
:
:
:
:
:
win
1/100
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

13. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

14. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

15. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

16. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

17. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100 $-1
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

18. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100 $-1
$0
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

19. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100 $-1
$0 $0
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
philosophy of religion – p. 3

20. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100 $-1
$0 $0
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
expected outcome if you play: (1/100 × $100) + (99/100 × −$1) = $0.01
philosophy of religion – p. 3

21. a lottery
:
:
:
:
:
:
:
:
win
1/100
lose
99/100
you
play
you don’t
play
$100 $-1
$0 $0
Is it rational to play if 100 tickets are sold for $1 and the prize is $100 ?
expected outcome if you play: (1/100 × $100) + (99/100 × −$1) = $0.01
if tickets cost $2: (1/99 × $100) + (99/100 × −$2) = −$0.98
philosophy of religion – p. 3

22. :
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:
philosophy of religion – p. 4

23. Pascal’s wager
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:
philosophy of religion – p. 4

24. Pascal’s wager
:
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:
God
exists
philosophy of religion – p. 4

25. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
philosophy of religion – p. 4

26. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
philosophy of religion – p. 4

27. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
philosophy of religion – p. 4

28. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
philosophy of religion – p. 4

29. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
small
loss
philosophy of religion – p. 4

30. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
small
loss
infinite
loss
philosophy of religion – p. 4

31. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
small
loss
infinite
loss
small
gain
philosophy of religion – p. 4

32. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
small
loss
infinite
loss
small
gain
expected outcome for belief: (? × ∞) + (? × −something) = ∞
philosophy of religion – p. 4

33. Pascal’s wager
:
:
:
:
:
:
:
:
God
exists
God does
not exist
you
believe
you don’t
believe
infinite
gain
small
loss
infinite
loss
small
gain
expected outcome for belief: (? × ∞) + (? × −something) = ∞
expected outcome for non-belief: (? × −∞) + (? × +something) = −∞
philosophy of religion – p. 4

34. :
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:
philosophy of religion – p. 5

35. the other religions objection
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:
philosophy of religion – p. 5

36. the other religions objection
:
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:
Yaweh
exists
philosophy of religion – p. 5

37. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
philosophy of religion – p. 5

38. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
philosophy of religion – p. 5

39. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
philosophy of religion – p. 5

40. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
infinite
gain
philosophy of religion – p. 5

41. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
infinite
gain
infinite
loss
philosophy of religion – p. 5

42. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
infinite
gain
infinite
loss
infinite
loss
philosophy of religion – p. 5

43. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
infinite
gain
infinite
loss
infinite
loss
infinite
gain
philosophy of religion – p. 5

44. the other religions objection
:
:
:
:
:
:
:
:
Yaweh
exists
Allah
exists
you believe
in Yaweh
you believe
in Allah
infinite
gain
infinite
loss
infinite
loss
infinite
gain
expected outcome whoever you believe in: (? × ∞) + (? × −∞) = 0
philosophy of religion – p. 5

45. belief and choice
philosophy of religion – p. 6

46. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
philosophy of religion – p. 6

47. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
philosophy of religion – p. 6

48. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
philosophy of religion – p. 6

49. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
Go to church.
philosophy of religion – p. 6

50. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
Go to church.
Associate with religious people.
philosophy of religion – p. 6

51. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
Go to church.
Associate with religious people.
Pray often.
philosophy of religion – p. 6

52. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
Go to church.
Associate with religious people.
Pray often.
. . . do these things long enough and belief will
come.
philosophy of religion – p. 6

53. belief and choice
Can you believe something that you have no
evidence for, even if you have an incentive to believe?
Pascal’s answer:
Act as if you believe . . .
Go to church.
Associate with religious people.
Pray often.
. . . do these things long enough and belief will
come.
Prudential reasons for belief can override lack of
evidential reasons.
philosophy of religion – p. 6

54. self-deception and wishful thinking
philosophy of religion – p. 7

55. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
philosophy of religion – p. 7

56. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
philosophy of religion – p. 7

57. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
Don’t look for evidence that supports what I don’t want to know.
philosophy of religion – p. 7

58. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
Don’t look for evidence that supports what I don’t want to know.
Over-emphasize evidence in favor of my preferred view.
philosophy of religion – p. 7

59. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
Don’t look for evidence that supports what I don’t want to know.
Over-emphasize evidence in favor of my preferred view.
Come up with other interpretations of the evidence and treat
them as more likely.
philosophy of religion – p. 7

60. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
Don’t look for evidence that supports what I don’t want to know.
Over-emphasize evidence in favor of my preferred view.
Come up with other interpretations of the evidence and treat
them as more likely.
Rely heavily on the opinions of people who haven’t seen the
evidence.
philosophy of religion – p. 7

61. self-deception and wishful thinking
“I know very well that my wife is having an affair, but I don’t want to
believe it . . . ”
“What can I do to convince myself that she’s not cheating on me?”
Don’t look for evidence that supports what I don’t want to know.
Over-emphasize evidence in favor of my preferred view.
Come up with other interpretations of the evidence and treat
them as more likely.
Rely heavily on the opinions of people who haven’t seen the
evidence.
Can these methods be used deliberately? Or do they only work as
automatic, unconscious mechanisms?
philosophy of religion – p. 7

62. infinite payoffs?
philosophy of religion – p. 8

63. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
philosophy of religion – p. 8

64. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
philosophy of religion – p. 8

65. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
philosophy of religion – p. 8

66. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
The expected outcome is ((1/2) × 2) + ((1/4) × 4) + ((1/8) ×
8) + ((1/16) × 16) + ((1/32) × 32) + . . . = ∞
philosophy of religion – p. 8

67. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
The expected outcome is ((1/2) × 2) + ((1/4) × 4) + ((1/8) ×
8) + ((1/16) × 16) + ((1/32) × 32) + . . . = ∞
If we spent eternity alternating between 5 minutes of bliss and 5
mintues of torture, we would experience both infinite bliss and
infinite torture.
philosophy of religion – p. 8

68. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
The expected outcome is ((1/2) × 2) + ((1/4) × 4) + ((1/8) ×
8) + ((1/16) × 16) + ((1/32) × 32) + . . . = ∞
If we spent eternity alternating between 5 minutes of bliss and 5
mintues of torture, we would experience both infinite bliss and
infinite torture.
Is anything we do ever enough to deserve an infinite payoff?
philosophy of religion – p. 8

69. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
The expected outcome is ((1/2) × 2) + ((1/4) × 4) + ((1/8) ×
8) + ((1/16) × 16) + ((1/32) × 32) + . . . = ∞
If we spent eternity alternating between 5 minutes of bliss and 5
mintues of torture, we would experience both infinite bliss and
infinite torture.
Is anything we do ever enough to deserve an infinite payoff?
Justice requires proportionality – worse crimes get worse
punishments.
philosophy of religion – p. 8

70. infinite payoffs?
Does it make sense to talk about infinite rewards or punishments?
The St. Petersburg paradox
How much would you pay to play a game where you get $2n
for every n flips of a coin until a head comes up?
The expected outcome is ((1/2) × 2) + ((1/4) × 4) + ((1/8) ×
8) + ((1/16) × 16) + ((1/32) × 32) + . . . = ∞
If we spent eternity alternating between 5 minutes of bliss and 5
mintues of torture, we would experience both infinite bliss and
infinite torture.
Is anything we do ever enough to deserve an infinite payoff?
Justice requires proportionality – worse crimes get worse
punishments.
But infinite reward or punishment cannot be proportional to any
finite act.
philosophy of religion – p. 8

71. Kant’s moral argument
philosophy of religion – p. 9

72. Kant’s moral argument
Either there are moral absolutes or anything goes.
philosophy of religion – p. 9

73. Kant’s moral argument
Either there are moral absolutes or anything goes.
But it is not true that anything goes – it is just plain wrong to kill
babies for fun.
philosophy of religion – p. 9

74. Kant’s moral argument
Either there are moral absolutes or anything goes.
But it is not true that anything goes – it is just plain wrong to kill
babies for fun.
So there must be moral absolutes.
philosophy of religion – p. 9

75. Kant’s moral argument
Either there are moral absolutes or anything goes.
But it is not true that anything goes – it is just plain wrong to kill
babies for fun.
So there must be moral absolutes.
In order to make sense of moral absolutes we must suppose that
there is a good God who is responsible for creating and enforcing
moral rules.
philosophy of religion – p. 9

76. Kant’s moral argument
Either there are moral absolutes or anything goes.
But it is not true that anything goes – it is just plain wrong to kill
babies for fun.
So there must be moral absolutes.
In order to make sense of moral absolutes we must suppose that
there is a good God who is responsible for creating and enforcing
moral rules.
So we must suppose that there is such a God, even if there is
absolutely no evidence that He or She exists.
philosophy of religion – p. 9