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Wagers and Evil
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Pascal’s Wager
Le silence éternel de
ces espaces infinis
m'effraie.
... from Pensées
(The eternal silence
of these infinite
spaces terrifies me.)
Blaise Pascal (1623-1662)
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Pascal’s Wager
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Prudential and Evidential Reasons for belief
– Suppose I offer you ten bucks if you believe that there
is life on Mars (assuming you don’t already)
– You don’t care one way or the other
– It’s an easy ten dollars
– You have a prudential reason to believe
– But you have no evidential reason to believe (based on
my offer)
– An evidential reason increases the probability of the
belief
● example: you learn that Mars has methane in its
atmosphere and it’s hard to think of any source
except living organisms
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Pascal’s Wager
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●
Blaise Pascal
– philosopher of the 17th century
– invented the theory of probability (with Fermat and the
Chevalier de Mere)
● after being asked about a gambling problem
● what are the chances – when rolling dice – of getting
10 and of getting 9?
– invented decision theory
What is the ‘expected utility’ of an action
– multiply the chance of the action succeeding by the
‘payoff’ (utility) of the successful outcome
– example: flipping coins, if you win $1.00 each time you
flip and win then what is the expected utility of a flip
– $1.00 (payoff/utility) x 0.5 (chance) = $0.50 (Exp Ut.)
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Pascal’s Wager
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What is the expected utility of this game:
– You get paid $1 if you roll a die and get 6
– What is the expected utility of rolling?
● 1/6 x $1 = about 16 cents
● What should you pay to play this game
What about Lotto 649
– Prize = $2M
– Chance of winning = 1 in 14M
– What is expected utility
● 2M / 14M = about 14 cents (very crude estimate)
What is the expected utility of this complex game:
– You flip a coin. You get paid $2n where n is the number
of time you get heads in a row (game over with tails).
– EU = 2x.5 + 4x.25 + 8x.125 ...... = ?? infinity
– what should you pay to play? (St. Petersburg paradox)
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Pascal’s Wager
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●
Pascal gave an argument which presents a prudential
reason to believe in God.
Here is the payoff matrix:
Believe in God
God exists
God does not
exist
Do not believe in God
Plus infinity
Minus infinity
A small negative
A small positive
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Pascal’s Wager
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To figure out the expected utility, you need the probability
of God existing, P(G) = ε
Suppose it is NOT zero, ε > 0
Thus the expected utility of belief is positive infinity!
Believe in God
God exists
God does not
exist
Plus infinity
x
Do not believe in God
Minus infinity
ε
A small negative
x
1-ε
x
ε
A small positive
x
1-ε
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Pascal’s Wager
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Problems
– It is impossible to ‘decide to believe’ (Doxastic
voluntarism)
● Try to believe, really believe, that there is an
elephant in the room right now.
● Pascal’s reply: one can engage in actions that will
tend to make one believe (go to church, make
religious friends, read the bible, etc.)
– The decision matrix is incomplete
● What if there is a God who punishes believers
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Pascal’s Wager
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Suppose
– Either God A or God B exists
– God A imposes eternal punishment on those who
believe in God B
– Same for God B (mutatis mutandis)
Believe in God A
God A exists
God B exists
Believe in God B
Plus infinity
Minus infinity
Minus infinity
Plus infinity
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Pascal’s Wager
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Why take any argument like Pascal’s seriously?
– The benefit is purely speculative
– What is the special attraction of religion
– Freud’s answer
William James’s version of the wager
– Pragmatism: truth = the useful
– For most beliefs, evidence matters
– For some, there is no evidential grip
– Religious beliefs are of this kind
– They provide a ‘vital benefit’
– They are ‘low cost’ evidentially
William James (1842-1910)
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Pascal’s Wager
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Clifford’s reply
– It is wrong to believe without evidence
If I steal money from any person, there may be no
harm done from the mere transfer of possession;
he may not feel the loss, or it may prevent him
from using the money badly. But I cannot help
doing this great wrong towards Man, that I make
myself dishonest.
In like manner, if I let myself believe anything on
insufficient evidence, there may be no great harm
done by the mere belief; it may be true after all, or
I may never have occasion to exhibit it in outward
acts. But I cannot help doing this great wrong
towards Man, that I make myself credulous.
The danger to society is not merely that it should
believe wrong things, though that is great enough;
but that it should become credulous, and lose the
habit of testing things and inquiring into them; for
then it must sink back into savagery.
William Kingdon Clifford (1845-1879)
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The Problem of Evil
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The Problem of Evil
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Here is an argument against the existence of God.
– If God is omniscient, he knows if there is evil.
– If God is omni-benevolent, he abhors evil.
– If God is omnipotent he can eliminate what he abhors
– God is omni-s/b/p
– Therefore there is no evil if God exists.
– But there is evil.
– Therefore God does not exist.
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The Problem of Evil
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Possible replies
– Since the argument is deductively valid, the only way
to attack it is to show that a premise is false.
– So, perhaps the idea that God is omni-s/b/p is wrong
● What would such a new God be like?
– Recall Greek pantheon
– Manicheanism / Zoroasterianism
● Worship and the properties of God
● What is the difference between this ‘weak’ God
and some ‘super alien’ being?
● Suppose we were created by
technologically advanced
aliens
– would you worship them?
– would they count as God?
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The Problem of Evil
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Possible replies
– The premise which asserts that if God exists then
there is no evil can also be attacked.
Soul Improving Evil
– Some bad things make us better people.
● You have to let a baby fall for it to learn to walk
– God wants us to be as good as possible.
– Therefore, soul improving evil is – on balance – good
worthwhile.
But ... are all evils soul improving?
– what about acne?
● Why should God care?
● 3-o/b/p cares about all
Are there soul destroying evils?
– Why are they permitted?
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The Problem of Evil
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Possible replies
– The premise which asserts that if God exists then
there is no evil can also be attacked.
The Free Will Defense
– Maybe a world in which there are free beings is better
than a world of ‘robots’
– If there are free beings, they can do evil
– Many evils are explained this way
– Two questions:
● Why can’t free beings freely always do good?
– Possible worlds can be used to explain this
● Are all evils the result of freedom of will?
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The Problem of Evil
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The Problem of Natural Evil
– Natural evils are evils that are not the result of the
free will of any agent
– Earthquakes, famines (most often), diseases (most
often), hurricanes, tornadoes, floods, avalanches ...
– Example: Lake Nyos
● Northwest Cameroon
● 1986 CO
cloud
2
● about 1800 died
● plus 3500 livestock
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The Problem of Evil
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More natural evil
– parasitic wasps
●
–
baby spiders eat their own mother
●
–
Darwin: ‘I cannot persuade myself that a beneficent and
omnipotent God would have designedly created the Ichneumonidae
with the express intention of their feeding within the living bodies of
Caterpillars’
the babies literally suck their mothers dry. After several weeks the
mother becomes so weak she can hardly move. At this point the
spiderlings attack their mother just as they would prey, injecting
her with venom and digestive juices and consuming her entirely
Human parasites
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The Problem of Evil
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Replies to the problem of natural evil:
– One reply is to reduce natural evil to willed evil
● How is this possible?
● Invoke the minions of Satan ...
– Another reply is simple
● The ways of God are mysterious to a finite
intelligence that can observe only a tiny part of
the universe
● Analogy: a very beautiful picture could have a very
ugly part in it
– Note the difference between these two replies
● The first accepts that natural evil is not necessary
● The second has to say that all the natural evil we
observe makes the universe better than it
otherwise would be
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The Problem of Evil
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Example:
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The Problem of Evil
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Example:
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The Problem of Evil
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Note the difference between these two replies
● The first accepts that natural evil is not necessary
– This again raises the question of why God did
not make the world in which Satan freely is
good rather than evil
● The second has to say that all the natural evil we
observe makes the universe better than it
otherwise would be
– This is hard to believe