(intro music)
My name is Sally Haslanger,
and I'm a professor of philosophy at MIT.
Today, we're going to discuss an argument
in favor of atheism,
in favor of the belief that God doesn't exist.
Let's start with some definitions.
"Theism" - that's "the belief that God exists."
So, "atheism": "the belief that God doesn't exist."
Rational theism is one form of theism.
It's the belief that there are evidential reasons
to believe that God exists.
Now, arational theism is the belief in God without evidence.
There are plenty of people who are arational theists,
because they believe in God based on faith.
Faith is often thought to be believing something
in spite of the fact that you don't have evidence for it,
and it's completely common for people
to believe things without evidence, right?
We believe things all the time based on wishful thinking.
We believe it because it's just in the air,
or it's convenient for us to believe it.
It makes us happy for us to believe it.
All those sorts of things.
But we're talking here about evidence,
where "evidence" is "some information
"that lends credibility to the claim,
"in the sense that it's more likely to be true
"if you have the evidence."
Okay, so arational theism, as I said,
is a common position,
but we're not really gonna talk very much about it today.
Irrational theism is the belief in God
in spite of evidential reasons supporting atheism.
Notice that this is quite different from arational theism.
The belief in God without evidence, as mentioned,
could be just on the basis of a lack of evidence.
But irrational theism is when you hold belief in God,
that is, when you hold theism,
but there are clear supporting reasons
for the opposing view, that is, for atheism.
Now, that's problematic, and we're gonna look
a little bit further into why it's problematic.
Let's move on to a few more definitions
so that we're clear what we're talking about.
"Contradiction" - what is a contradiction?
A contradiction is when you have a set of beliefs
that are not possibly true together.
So a set of beliefs is contradictory if and only if
it's not possible for all of them to be true.
Here's a simple example:
"Today is Monday.
It's not the case that today is Monday."
Those can't both be true together.
Now, we're making an assumption: mainly,
that we're talking about right here right now.
We're not talking about something
on the other side of the dateline.
Considering "today is Monday,"
and "it's not today is Monday,"
that's a contradiction.
Both of them can't be true.
So if you believe both of them,
then you're believing a contradiction.
Now, it's not necessarily the case
that a contradiction needs to involve only two statements.
It can involve three statements.
So "all birds can fly," "penguins are birds," "penguins can't fly."
Not all of them can be true together, right?
If you hold what it is to fly stable,
if you hold what it is to be a bird stable,
then you can't hold all these together
and have just true beliefs.
One of them has got to be false.
Now you could say,
"Well, maybe it's not the case that all birds can fly,"
or, "Maybe it's not the case that all penguins are birds,"
or maybe you could come up with a modification
of what it is to fly so that penguins can fly.
They're really good underwater, for example.
You watch them under water, they look like they're flying.
But that's not really flying.
So you can't hold all of these beliefs.
You have to figure out which one you're going to give up.
Likewise, "today is Monday"
and "it's not the case that today is Monday" -
you need to give one up.
Okay, now why do you have to give one up?
Some people say,
"Wait, we believe in contradictions all the time.
"It's just not obvious that we believe in contradictions."
Well, that's true.
We probably do have contradictory beliefs,
but it's not good to have contradictory beliefs.
We want to get rid of our contradictory beliefs.
Now there are a couple of reasons why.
First of all, it's really good to have true beliefs.
You don't want to go around the world having false beliefs,
cause it gets you into trouble.
So if I believe that there's no wall here,
and I go walking into the wall,
then that's not so good.
False beliefs can get you into trouble in that way.
They can lead you into problematic circumstances
that you'd probably best not be in.
So holding beliefs that are false is problematic,
and if you hold contradictory beliefs,
you know one of them has got to be false,
and that's bad.
Another thing is coherent action.
Having contradictory beliefs makes it difficult
to act coherently.
Look at this one:
"Today is Monday, and it's not the case that today is Monday."
Suppose you have a dentist appointment on Monday.
What do you do?
Do you go or not?
You both believe that it is and it isn't Monday,
so what are you gonna do?
It's hard to act coherently and act in a sensible way
to fulfill your obligations, etcetera.
Since one of the beliefs you hold has got to be false,
and you can't act on two contradictory beliefs,
you can't really act coherently.
So we're talking about whether God exists,
and evidence for and against the existence of God.
Now, there are many different conceptions of God or gods.
I'm not trying to adjudicate what's the right
or best conception of God.
But there's a particular standard definition in the West,
that God is an all-perfect being,
a being at least who has these three features:
a god is all-knowing (which is to be omniscient),
all-powerful (which is to be omnipotent),
and to be wholly good (or omnibenevolent).
So this being is perfect,
is omniscient, omnipotent, and wholly good,
(or omnibenevolent).
We're gonna call the combination of these features "OOO" ("O-O-O")
because they're pretty good ooo features.
Let's go ahead and now look at the argument
that suggests that atheism is the rational view to hold,
the one that there's the greatest evidence to believe.
Here's the first premise:
if God exists, he, she, or it would be OOO.
Now I use "he, she, or it" because, of course,
I don't know whether there's a God,
and if there is, whether it's a he, she, or it,
or at least for the purposes of the discussion,
we're not gonna assume anything like that.
Okay, so that's the first premise.
Second: if an OOO god exits, there would be no evil.
Well, why's that?
Well, if a god were all-knowing,
then that god would know when evil was going to occur
(or that it occurred),
would have the power to make it not occur,
and is wholly good, so would also have the motivation
to make it not occur.
So this combination of omniscience, omnipotence,
and omnibenevolence suggests that if a god were truly OOO,
there would be no evil.
We assume for the purposes of argument that God exists.
And we conclude, then, there is no evil.
So if God exists, he, she, or it would be OOO.
If an OOO god exists, there would be no evil.
God exists, so there is no evil.
The problem is, there is evil.
Well, at least, it seems there's evil.
That might be one of the questions that comes up
when we consider objections to the argument.
It appears, certainly appears, that there's evil:
lynching, terrorism, the death of innocent babies.
So for the moment, we're gonna say there is evil.
But look: "there is no evil," "there is evil" -
this is a contradiction.
And so we have to reject one of these premises.
Well, this one, that God is OOO,
that one is hard to reject
because that's just how we've defined what God is.
This one - it seems straightforward.
And so once we assume God exists,
and we assume that there is evil in the world,
which is hard to deny, we get a contradiction.
So we have to reject something.
And so the thing that's most likely to be false,
according to the argument, is number (3),
that God exists.
So we conclude that God does not exist.
Now this argument is a little bit truncated,
as any argument is.
It relies on two further assumptions.
First, a wholly good thing always eliminates evil
as far as it can.
And second, that there are no limits to what
an omnipotent thing can do.
But these just seem to be part of the definition of
all-knowing, all-powerful, and wholly good.
It's just true by definition.
So here's a way to think about it.
If we assume a certain kind of God, an OOO God,
and we really take seriously the perfection of that God
(all-knowing, all-powerful, omnibenevolent,)
then once we assume that kind of God,
and that there exists some evil in the world,
then we've got a contradiction.
So the theist is left with this position:
either the theist has to say there is no evil in the world,
or the theist has to give up
one of these features of their God.
Those are your two options.
Neither of them look very appealing.
And so now we're in a position to say,
"If you don't want to do that,
"you are an irrational theist,"
that there is compelling evidence that God does not exist,
God of this OOO kind does not exist,
and yet, you believe anyway.
That is to say, you believe a contradiction.
You believe that there is evil, and there is no evil.
You believe that there is this kind of god,
there isn't this kind of god.
We saw before that belief in contradictions is a bad thing,
and you ought to avoid it wherever you can.
And so this is the argument that you should not be a theist,
because irrational theism
is not an acceptable form of theism.
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