All right, we're going to talk today about Pascal's Wager, a brief section from the Course Reader.
I thought I'd start on this board by contrasting different ways philosophers have approached
the question of God's existence and using reason try to prove it.
So previously, in the previous course, we read Thomas Aquinas’ Five Ways.
A couple of important points to note about those:
they are proofs that always begin with experience.
You remember from my class: every one of Aquinas' five ways starts with an observation about
the way the world is.
We observe in the world that some things are in motion, or that some things are contingent,
or that some things act for the best, system.
Aquinas then applies metaphysical principles and reasoning to those facts about the world.
But he always… one of his premises is always a factual premise about the way the world
happens to be.
We live in a world in which things are in motion, things are changing, things are contingent,
et cetera.
And then he reasons forward from that to the conclusion that there must be… because of
the way the world is, there must be some being outside of the world, to whom those same principles
do not apply.
There must be an uncaused cause, there must be a source of motion which is not itself
in motion or changing, there must be a necessary being that is not itself contingent, there
must be a being that is the ground of its own being.
We won’t walk through those proofs again.
But these proofs are all what philosophers call “a posteriori.”
Meaning they begin in experience, they begin with observations about the world.
Descartes’ proof of God, which we’ve been over much more recently, begins with ideas,
precisely because Descartes has disregarded all of his senses, all of his bodily knowledge,
everything that came to him in any way from his senses or his body he has set aside temporarily
in his thought experiment, and he's left with his innate idea of God.
And from this he reasons that God must exist as the cause of this innate idea.
There's no other possible cause for it.
We go through the three classes of ideas and rule them out: it’s not adventitious, it’s
not caused by me, it must be innate.
And the idea is of such a character, has such a perfection to it, that it must have a perfect
being as its cause.
Notice that makes no appeal to experience which is why philosophers would call it an
“a priori” proof, a proof that is prior to experience.
It doesn't require any sort of observation about the way the world is because this level
of reasoning about God is prior to any experience we have of the way the world is.
Now Descartes thinks the value of this proof is that this type of proof holds even if I
am absolutely mistaken about the rest of the world.
Even if all my senses are globally deceiving me I can still believe, just reasoning from
the fact of my existence and the existence of this innate idea in my mind, I can come
to the conclusion that God exists.
And this was his reason for saying that I am more certain of the truth that God exists
that I am certain of any other truth about my body or any kind of sense knowledge that
I have.
He’s setting the bar very high for the importance of this knowledge.
We come to Pascal though, who’s writing just a generation or half a generation after Descartes.
He’s reacting to Descartes, he doesn't think the Cartesian rationalist approach, still
very heavy into metaphysics in this a priori argument, he doesn't think this is right way
to do philosophy and he doesn't think this is the right way to think about God.
And so we get, at the beginning of the Wager, the assertion that reason cannot determine
the question of God's existence for us, not in the way that Pascal wishes.
It's not enough to motivate belief and a change of behavior or a reform of life.
So we get instead a probabilistic style of reasoning.
We get Pascal reasoning about risk versus reward, about the possible upsides and the
possible downsides of believing or not believing in God, in a situation where it’s impossible
to know for certain whether God exists or not.
So Pascal begins by denying what Descartes thinks he’s done, which is to prove with
absolute certainty beyond a shadow of a doubt that God exists.
Pascal says let’s look at the situation where we don't know, and let’s think the
way that gamblers think.
Because this is exactly what gamblers do all the time.
Not knowing which way the dice will come out or what slot the ball on the roulette wheel
will land in, I have to make a calculated wager based upon my knowledge, my expectations
of what’s going to happen.
I can count cards, I can figure out how many cards, how many face cards are left in the
shoe, I can adjust my wager according to that.
That that kind of rationality is what Pascal is drawing on now in his Wager.
Not the kind of metaphysical reasoning that Descartes uses, a priori style, and not the
kind of metaphysical reasoning that Aquinas uses in his a posteriori style, beginning
with observations about the world.
Instead, he gives us a probabilistic reasoning which gives us reasons for belief, but not
absolute proof.
It’s precisely because we can't have an absolute proof that Pascal thinks that the
appropriate way to approach the question God is with this, with this probabilistic wager.
So we’ll take a look at the reasoning structure of the wager, the logical structure of it,
we’ll ask whether it is persuasive, and we’ll ask what assumptions are loaded into
this wager, what assumptions about the human person and what assumptions about the character
of rationality and philosophical proof.