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The Existence of God
CLASSICAL PROOFS
Classical Arguments
There are three ‘classical’ arguments for the
existence of God:
• The cosmological argument
• The teleological argument
• The ontological argument
Cosmological Argument
Premise 1: All motion we observe is derived
motion; things that move have their momentum
imparted by earlier moving things that moved
them, which in turn were themselves moved by
earlier moving things, etc.
Premise 2: This process can’t stretch back
infinitely.
Conclusion: There must be an ‘unmoved mover’
that started the process. This is God.
Variant
Premise 1: All events we observe are contingent
(might not have happened) and caused by
earlier contingent events, which in turn were
caused by still earlier contingent events, etc.
Premise 2: A causal chain, all of whose links are
contingent, can’t stretch back infinitely.
Conclusion: There must be a non-contingent
(necessary) first cause. This is God.
The Idea
The idea here is that contingent things require
explanations. Because they could have not
happened, we have to explain why they did
happen. There can’t be an infinite chain of
explanations that doesn’t “ground out”
somewhere. Necessary things, since they must
happen, require no explanation: there’s no
other way for things to have gone. So a
necessary thing must be the original source for
all the contingent events.
Common Criticisms
1. God is claimed to have these properties
(unmoved mover, necessary existence), but no
evidence is offered.
2. An unmoved mover or a necessary being might
not be God. The argument doesn’t tell you the
unmoved mover loves humanity or even that it
thinks at all.
3. There’s no logical reason that a chain of derived
motion/ contingent causes can’t stretch back
infinitely.
Paley’s Analogy
“In crossing a heath, suppose I pitched my foot
against a stone and were asked how the stone came
to be there, I might possibly answer that for
anything I knew to the contrary it had lain there
forever; nor would it, perhaps, be very easy to show
the absurdity of this answer. But suppose I had
found a watch upon the ground, and it should be
inquired how the watch happened to be in that
place. I should hardly think of the answer which I
had before given, that for anything I knew the
watch might have always been there…
Paley’s Analogy
Yet why should not this answer serve for the
watch as well as for the stone? Why is it not as
admissible in the second case as in the first? For
this reason, and for no other, namely, that when
we come to inspect the watch, we perceive—
what we could not discover in the stone—that
its several parts are framed and put together for
a purpose.”
The Teleological Argument
Premise 1. All around the world we see complex
aspects of nature that serve a valuable purpose,
and could not serve that purpose if they were
any different.
Example: The human eye is complex, allows us
to spatially locate ourselves and other objects in
our environment almost instantaneously, and
could not function if any of its many interacting
parts were different from how they are.
The Teleological Argument
Premise 2: It is impossible or at least
extraordinarily unlikely that complex purposeserving adaptations could come about by
“blind” unguided natural processes.
Conclusion: Therefore, structures like the human
eye were consciously designed by an intelligent
creator. This intelligent being is God.
Hume’s Criticisms
1. Even if the argument proves a designer’s
existence, it cannot prove God’s existence.
God is all good, but there are complex
purposeful adaptations in nature that do
nothing but cause pain and suffering (e.g.
AIDS virus). The designer is not all good.
2. Similarly, God is all powerful/ intelligent. But
poor design (human sinus) shows that the
designer is either incapable or incompetent.
Hume’s Criticisms
3. Nothing in the design argument rules out the
universe having multiple, distinct designers.
4. Accepting the conclusion of the argument
(the existence of a designer/ God) presents us
with a regress. For God presumably has complex
parts that work together to serve a valuable
purpose. So God too must have been designed
by another designer. And that designer too must
have been designed, etc.
Darwin
The teleological argument suffered most at the
hands of Darwin, who showed how complex
adaptations could arise by natural means, via a
process of random generation and natural
selection. Random mutations generate new
anatomical structures; if they are beneficial, the
genes that produce them proliferate; if they are
harmful, a quick death removes them from the
gene pool.
The Fine-Tuning Argument
A contemporary version of the teleological
argument is the “fine-tuning” argument.
Premise 1: There are fundamental physical
parameters, like the strength of gravity, the
strength of electromagnetism, and the strength
of the strong nuclear force. If these were only
slightly different, life could not possibly exist.
The Fine-Tuning Argument
Premise 2: It is highly unlikely that a universe
with randomly-selected values for these
parameters would support life.
Conclusion: The parameter values were selected
by an intelligent being that desired life in the
universe.
Criticisms
The Anthropic Principle: In order for life to
observe the fine-tuning of the universe, the
universe has to be fine-tuned. We’re not in a
randomly selected universe, we’re in a randomly
selected fine-tuned universe.
Most of the universe contains no life, and
complex life on Earth has existed for only a very
short period of time. If the creator wanted life,
this is a funny way to make it!
The Ontological Argument
1. God is, by definition, the greatest being
conceivable.
2. Things that exist are greater than things that
don’t exist.
3. If God does not exist, then we can conceive
of a greater being: something just like God,
but that does exist.
4. But that’s a contradiction with (1).
Therefore, God exists.
Criticism: The Perfect Island
1. Define Paradise = the greatest island
conceivable.
2. Islands that exist are greater than islands that
don’t exist.
3. If Paradise does not exist, then we can
conceive of a greater island: something just
like Paradise, but that does exist.
4. But that’s a contradiction with (1).
Therefore, Paradise exists.
Criticism: Hume on A Priority
The ontological argument does not rely on any
assumptions about how things actually are.
Therefore if it’s a good argument, then the
conclusion is true, no matter how things are.
Therefore, it should be impossible to imagine
the conclusion being false. But it’s trivially easy
to imagine our world existing, but with no God
in it. So the argument must go wrong
somewhere.
Criticism: Kant on Existence
Kant’s famous response to the ontological
argument was to claim that “existence is not a
predicate.” The main idea was that imagining
God and imagining something-just-like-Godthat-existed was the same thing. To imagine a
thing is to imagine its existence. Therefore
premise (3) is wrong: even if God does not exist,
we can’t imagine anything greater than God.
PASCAL’S WAGER
Types of Reasons
There is a variety of types of reasons in the
world:
Moral reasons: You ought not to kill babies for
fun, because it is morally wrong to do so.
Prudential reasons: You ought not to cut off your
fingers, because it is not in your best interests.
Epistemic reasons: You ought not to believe that
smoking is healthy, because the evidence says
otherwise.
Reasons for Belief
Clearly most of our reasons for our beliefs are
epistemic reasons. Sometimes we hold beliefs
for non-epistemic reasons: I might believe my
wife is faithful, despite all the evidence to the
contrary, because it makes me feel good. Or I
might believe that different races of people
were equally smart, even in the face of
compelling counterevidence, out of a moral
conviction regarding equality.
Evidentialism
However, we largely regard holding beliefs for
non-epistemic reasons to be irrational. I should
not (rationally) believe my wife is faithful, if the
evidence says otherwise. And even if it flies in
the face of my moral convictions, I should
(rationally) believe what the evidence suggests
to be true, even if it’s morally wrong to do so.
Evidentialism is the philosophical doctrine that
only epistemic reasons (evidence) are relevant
to what we should rationally believe.
Prudential Reasons for Believing in
God
There is, however, an interesting argument put
forth by Blaise Pascal, that we should believe in
God no matter what the evidence says,
regardless of what epistemic reasons we have.
We have an overwhelming prudential reason to
believe in God’s existence, one that trumps any
epistemic reasons we might have. Evidentialism
is false, if Pascal is right.
Blaise Pascal (1623-1662)
Blaise Pascal
Pascal was a mathematician, physicist, and
philosopher. Among his many achievements, he
invented the mechanical calculator, discovered
Pascal’s triangle, and was one of the early
pioneers in probability theory and decision
theory.
No Epistemic Reasons for God’s
Existence
“If there is a God, He is infinitely
incomprehensible, since, having neither parts
nor limits, He has no affinity with us. We are
incapable, therefore, of knowing either what He
is or if He is. That being so, who will dare
undertake to decide this question? Not we, who
have no affinity with Him. Who then can blame
the Christians for not being able to give reasons
for their belief, professing as they do a religion
which they cannot explain by reason.”
Decision Theory
Decision theory is the mathematical discipline
devoted to calculating the prudentially best
course of action. While Pascal believes there
cannot be an epistemic reason for belief in God,
he thinks decision theory can show us there is
an excellent prudential reason for such belief.
Problem Specification
Solving a decision problem begins with a
problem specification, breaking down the
problem into three components:
1. Acts: the various (relevant) actions you can
take in the situation.
2. States: the different ways that things might
turn out, and the probabilities of each.
3. Outcomes: What results from the various
acts in the different states.
Example
For example, consider a simple decision problem
involved in betting on a sports team:
1. Acts: Bet on the Dragons, bet on the Cherry
blossoms.
2. States: Dragons win (1-to-4 odds), Cherry
Blossoms win.
3. Outcomes: +$500 for successful bet on
Dragons, +$300 for successful bet on Cherry
Blossoms, -$200 for any lost bet.
Decision Tables
Decisions, after being analyzed by a problem
specification, can be summarized in a decision
table, with the Acts on the left, the States on the
top, and the corresponding Outcomes (plus the
probabilities of those Outcomes) for each Act,
State pair in their appropriate locations.
Example Table:
Dragons Win
I bet on
+$500
Dragons
I bet on Cherry -$200
Blossoms
Cherry
Blossoms Win
-$200
0.2
0.8
+$300
0.2
0.8
Expected Value
The expected value of an act is the weighted
average of the values of the outcomes of the
act. The outcomes of betting on the Dragons, for
example, are +$500 and -$300. How do we
weight them? By the probability that we’ll
receive each value. If the Dragons have a 20%
chance of winning, the EV of a bet on them is:
$500 x 20% + -$300 x 80% = -$140
Maximize Expected Value
According to decision theory, the act you should
(prudentially) choose– the one that’s in your
best interest– is the act that maximizes expected
value.
One way of justifying this is that the Law of
Large Numbers says that if you bet on games
exactly like this a large number of times, on
average you will receive the expected value of
each bet.
Pascal’s Wager
Here’s the decision problem as Pascal sees it:
Acts: Either you can believe that God exists, or
you can not believe that God exists.
States: Either God does in fact exist or He does
not. (Ignore the probabilities for now.)
Outcomes
1. You believe in God, and He exists: an
“eternity of life and happiness” in heaven.
2. You believe in God, and He does not exist:
some wasted time in church.
3. You don’t believe in God, and He exists: no
heaven (maybe hell?).
4. You don’t believe in God, and He does not
exist: free time on Sundays (Saturdays).
Decision Table
God exists
Believe in God +∞
Don’t believe
in God
+finite amt
God does not
exist
-finite amt
+finite amt
No Probabilities, Numbers Needed
There are no probabilities or specific numbers
indicated in this decision specification. Why? It
doesn’t matter:
The maximum expected value of “don’t believe
in God” is always going to be identical to the
maximum outcome, which is always finite.
The Wager
The minimum expected value of “believe in
God” is always going to be +infinity, provided
that there is a non-zero probability that God
exists.
Since obviously there’s a non-zero probability of
God’s existence, and +infinity is greater than any
finite number (the max expected value of
disbelief), Pascal says you should always believe
in God.
The Other Gods Problem
One common response to Pascal’s wager has
been that it can’t be correct, because it equally
recommends a belief in any other deity (that
promises an infinite reward). As such, it
recommends belief in no deity at all, because
there’s no way of choosing.
Zeus
God exists
Believe in Zeus +∞
Don’t believe
in Zeus
+finite amt
God does not
exist
-finite amt
+finite amt
Criticisms
Other common criticisms:
• The wager assumes doxastic voluntarism: that
our beliefs are under our control.
• It assumes God wants us to believe regardless
of the evidence.
• It assumes that it’s possible for prudential
reasons to rationally justify a belief. (Assumes
that evidentialism is false.)
THE WILL TO BELIEVE
William James (1842-1910)
William James
William James was an introspectionist
psychologist and an American pragmatist
philosopher. (Pragmatism, remember, was
founded by Pierce.) James also famously argued
against evidentialism, and even quotes Pascal:
“Le cœur a ses raisons, que la raison ne connaît
point.” The heart has reasons that reason never
knows.
Hypotheses and Options
James starts out by introducing some
terminology:
Hypothesis: something we can potentially
believe.
Option: a choice between two hypotheses.
Properties of Options
• Living or dead: a living option is one where
you can seriously entertain the possibility of
believing either hypothesis.
• Forced or avoidable: an avoidable option is
one where you can choose not to believe
either hypothesis.
• Momentous or trivial: a trivial option is one
where accepting either of the hypotheses
doesn’t affect you very much.
Genuine Options
James calls an option genuine if it is forced,
living, and momentous. You cannot avoid the
choice, both hypotheses appeal to you
somewhat, and your decision matters a lot.
Response to Doxastic Voluntarism
James concedes that what we believe is not fully
under the control of our wills.
However, he thinks this has to do with the living
vs. dead distinction. If an option is dead, and we
can only seriously entertain one of its
hypotheses, then we cannot by force of will
entertain the other. But belief in either
hypothesis of a live option is a matter of will.
Principles of Belief
James says there are two principles we try to
satisfy when forming beliefs:
1. Believe the truth.
2. Don’t believe false things.
We can satisfy (2) by believing as few things as
possible, and satisfy (1) by believing as many. It
is a balancing act to satisfy both at once.
Most Speculative Issues are Trivial
Most speculative issues, according to James, are
trivial: it doesn’t matter to our lives, James says
whether we:
• Have a theory of the nature of X-rays.
• Believe in dualism, that the mind is a different
substance than matter.
• Believe that conscious states can have causal
effects.
Warranted Skepticism
Because the issues are trivial, James thinks that
an aloof skepticism is warranted. We should
simply suspend belief in, say, dualism vs.
materialism, because it doesn’t matter. That
doesn’t mean we shouldn’t keep investigating
the issue– it’s just that there’s no particular
reason for commitment either way.
Warranted Skepticism
“Wherever the option between losing truth and
gaining it is not momentous, we can throw the
chance of gaining truth away, and at any rate
save ourselves from any chance of believing
falsehood, by not making up our minds at all till
objective evidence has come.”
The Scientific Method
On James’ view, scientific matters should be
conducted in ways that avoid error, at the cost
of being overly cautious– because getting the
truth right is not that important. Science has
thus codified a method that is overly cautious–
and that’s a good thing. However, it is wrong to
then apply that method to momentous options.
There, avoiding error at all costs is
inappropriate.
Faith Creates Facts (Sometimes)
James says there are cases “where faith in a fact,
based on need of the fact, can create the fact.”
An example he gives is friendship. If I don’t
believe you like me, because I don’t have any
evidence that you do, you’re unlikely to like me.
Whereas if I believe that you like me, on faith,
then it is more likely to be true that you like me.
Religion
What about religion?
First, James says, religion presents us with a
momentous choice
For some it might not be living, but he has
nothing to say to those people.
It’s forced in the sense that to accept religion or
not accept it exhausts the logical options.
So whether to accept religion is a genuine
option.
Faith Creates Evidence (Sometimes)
Clearly, believing in God doesn’t make God exist
(although later in life, James came to believe
this). However, James thinks only a belief in God
opens the door for evidence of God’s existence.
If we are too skeptical and scientific, God “won’t
like us” and then we will never get the evidence
of His existence.
Conclusion
James identifies two specific circumstances
where he thinks evidentialism fails: self-fulfilling
beliefs, where having the belief makes it true/
more likely to be true, and beliefs where having
them makes it more likely that you will get
evidence for them (if such evidence exists).
Conclusion
When the issues are trivial, we might still
suspend belief, to avoid falsehood. But when
they are momentous, like with religion,
suspending belief can be catastrophic. Thus
rationality recommends belief in religion even
when the evidence does not support such belief.
Criticism
The obvious problems with this approach are
that James doesn’t really explain how belief in
religion is required for evidence for religion, he
just gives us a friendship metaphor.
Second, James doesn’t describe any of the
evidence he’s received for God’s existence after
willing to believe in Him.
Criticism
Third, the argument again seems too powerful:
if contradictory things all have the property
(belief in them increases likelihood of evidence),
then we’re led to believe contradictions.
For example, if I’m more likely to get evidence of
Zeus from believing in Zeus, and more likely to
get evidence of (the JC) God from believing in
God, should I believe in both?
HUME ON MIRACLES
Hume on Miracles
As I said last time, Hume’s Enquiry concerning
Human Understanding is mostly just a
shortened, beautifully written version of Part I
“Of the Understanding” of his earlier A Treatise
of Human Nature. However, there is one section,
Section X, of the Enquiry that is totally new: “Of
Miracles.” Hume added this mostly to rile up
people and get them to read and discuss his
work.
Degrees of Confirmation
Different claims are confirmed by out
experience in differing degrees:
Sometimes they are always confirmed: “An ice
cube melts after an hour in the sun.”
Sometimes they are sometimes confirmed:
“Birds fly.”
Sometimes they are rarely confirmed: “Thai
food is bland.”
Wisdom
Hume says:
“A wise man, therefore,
proportions his belief to
the evidence.”
You believe things “more”
when there’s more
evidence for them.
Example: Testimony
For example, suppose you have three friends:
Butter, Candice, and Dianne:
• Butter tells the truth very rarely.
• Candice tells the truth about half the time.
• And Dianne usually tells the truth.
If Dianne tells you something, and Butter tells
you the opposite, you should believe Dianne.
Mixed Evidence
Sometimes, we have “mixed” evidence– not just
testimony, but testimony AND observation AND
theoretical prediction AND…
For example, suppose while you’re walking
along with a friend, you get robbed. How old
was the guy who robbed you?
Example: Mixed Evidence
• Testimony: your friend was with you and he
thought the guy was between 38 and 42.
• Observation: to you he seemed younger,
between 30 and 34.
• Theoretical Prediction: the police have a
suspect– if the suspect is the robber, he was
39.
If you have to guess the robber’s age, you need
to use all the available evidence.
Karl von Frisch
Karl von Frisch was a
Nobel Prize winning
scientist who studied
bees, and bee
communication.
Laboratory Studies…
“If we use excessively elaborate apparatus to
examine simple natural phenomena Nature
herself may escape us. This is what happened
some forty-five years ago when a distinguished
scientist, studying the colour sense of animals in
his laboratory, arrived at the definite and
apparently well-established conclusion that bees
were colour-blind…”
vs. Field Work
“…It was this occasion which first caused me to
embark on a close study of their way of life; for
once one got to know, through work in the field,
something about the reaction of bees to the
brilliant colour of flowers, it was easier to
believe that a scientist had come to false
conclusion than that nature had made an absurd
mistake.”
Novel Testimony
Suppose now that we get testimony concerning
something we have never experienced.
Hume imagines someone from the equatorial
regions being told about frost, and snow, and
ice. They have never experienced anything like
that before.
It’s Strange!
Hume thinks this person would have reason to
disbelieve stories about a white powder that fell
from the sky, covered everything by several
inches, and then turned to water and went
away.
It’s not that they should believe the stories are
not true, just that they don’t have to believe
they are true. We need more evidence.
But suppose someone tells us an even stranger
story. It’s like the snow-story, in that we’ve never
experienced anything like it before. But it’s even
stranger, because we have always experienced
the opposite before.
Miracles
For Hume, this is the definition of a miracle. A
miracle is a violation of the laws of nature. Every
event or process in the world conforms to the
laws of nature (for example, the laws of physics
like the law of gravity)– except, if there are any,
miracles.
Example
There are about 100 billion people who have
lived and died in the history of humanity (and
there are 7 billion more who are alive now).
As far as we know, none of the 100 billion
people who have ever died and were dead for
four days, later came back to life. It’s a law of
nature that when you die, that’s the end, there’s
no more.
Lazarus
Although there is
testimony, in at least one
religious book– the
Christian bible– that such
an event occurred at least
once in history, when
Jesus raised Lazarus from
the dead, after he had
been dead for four days.
What Should We Believe?
According to Hume, we should be wise and
apportion our belief to the evidence.
Since on the one hand we have 100 billion
people who died and never came back, and on
the other hand we have an old legend from a
book intended to make people believe its
religious views, it’s most probable that the
raising of Lazarus never happened.
Hume on Miracles
“No testimony is sufficient
to establish a miracle,
unless the testimony be of
such a kind that its
falsehood would be more
miraculous than the fact
which it endeavors to
establish.”
Seeing and Believing
So, for example, Hume would even say that if
you saw someone die and come back to life, you
should not believe that it really happened.
Because it’s always possible that what you saw
was a trick, or the person was never really dead,
or you were on drugs or… Since none of those
suppositions are miraculous, you should believe
them instead of believing in the miracle. They’re
more likely than a violation of nature’s laws.
Problems with Testimony
It’s of course possible that the number of
independent witnesses to a miracle could
outnumber the times we have seen a certain
law of nature confirmed. If that were so, Hume
would have to accept the miraculous testimony,
provided the witnesses were reliable enough. So
Hume spends some time arguing that testimony
about miracles is not very reliable.
Problems with Testimony
Hume gives several reasons why testimony
about miracles is problematic:
1. There has never been a well-established,
independently corroborated miracle.
2. People have reasons to lie about miracles, to
convince others to believe their religion.
3. We have lots of evidence of fake miracles and
forgeries (e.g. the shroud of Turin).
Problems with Testimony
Finally, Hume argues, if there is at most one true
religion (and maybe none) then all of the other
religious holy books must contain false
testimony of miracles. Therefore, most
testimony of miracles is false. So upon receiving
testimony of a miracle, the most likely
supposition is that it is false.
SUMMARY
Summary
There are interesting epistemic issues
surrounding God and religion. (An interesting
one we didn’t cover: if God knows what will
happen in the future, does that mean I’m not
free to choose what to do?)
Some philosophers have argued against
evidentialism and for the idea that belief in God
can be rational, even if there’s no evidence for
God’s existence.
Summary
Other serious evidentialists, like Hume, have
argued not only that evidence is required for a
belief in anything, but that in the case of
religion, some putative evidence frequently
cited in its favor (testimony of miracles) cannot
in principle provide evidence for religion.
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