Illusions and Reality in Philosophical Thought
Bouwsma and the evil
demon
Bouwsma’s Goal
Bouwsma tries to show that in the evil demon scenario we are
not actually deceived.
Contrary to what Descartes assumed, in such a world all of our
ordinary beliefs are still true!
Demon vs. Tom Round 1:
Paper World
While Tom sleeps the demon replaces everything in the world
with paper.
Tom, though fooled (visually) at first, is easily able to uncover
the illusion by using his other senses.
Demon vs. Tom Round 1:
Paper World
Bouwsma draws two lessons from this case. First:
“An illusion is something that looks like or sounds like, so much
like, something else that you either mistake it for something
else, or you can easily understand how someone might come
to do this.” (117)
Demon vs. Tom Round 1:
Paper World
Second, an illusion requires that the deceived can “tell the
difference” between the illusion and reality.
This does not mean that one cannot be deceived by an illusion,
but one must be able to understand the difference between the
two (e.g. paper world vs. actual world).
Announcements
My office hours this week are cancelled for tomorrow. I will
hold my office hours on Friday from 11AM-1PM.
Thomson has been postponed again!
Tom vs. the Demon Round 2:
Demon World
While Tom sleep the demon destroys everything besides Tom
and makes it so that Tom will continue to think that everything
is just as it was yesterday.
Tom vs. the Demon Round 2:
Demon World
“There are to be no flowers, no Milly, no paper. There is to be
nothing at all, but Tom is every moment to go on mistaking
nothing for something, nothing at all for flowers, nothing at all
for Milly, etc…And yet all is to be arranged in such a way that
Tom will go on just as we now do…He will love flowers, he will
kiss Milly, he will blink at the sun. So he thinks…” (119)
Tom vs. the Demon Round 2:
Demon World
In this case there is no way, even in principle for Tom to detect the
change.
All his perceptual experiences are identical to what they were
before.
This is just like our cases of radical deception (Matrix/BIV/Evil
Demon)
Tom vs. the Demon Round 2:
Demon World
In Bouwsma’s story the Demon attempts to explain to Tom the
nature of his deception.
In response Tom claims that by “flower” he just means “thing
that smells, feels, looks, etc. this way.”
According to this line of thinking, the demon has not created a
world in which there are no flowers and Tom is not deceived!
Thick vs. Thin Illusions
Thin Illusion
: e.g. lowers in a mirror and paper flowers; they
only
look like
flowers. They do not have
all
of the qualities a
flower has.
Thick Illusion:
A demon flower. Mirrors
all
the properties of a
flower. It looks, feels, smells, tastes, etc. like a flower.
Thick vs. Thin Illusions
Tom’s reply:
“I see that what you mean by thin illusion is what I mean by
illusions, and what you mean by thick illusions
is what I mean
by flowers
. So when you say that my flowers are your thick
illusions this doesn’t bother me. And as for your mirror that
mirrors all layers of your thick illusions, I shouldn’t call that a
mirror at all.
It’s a duplicator
.” (78)
Thick vs. Thin Illusions
The demon replies that HE has a sense by which he can tell
real flowers from demon flowers: (thick illusions from reality).
Tom lacks this sense, so he can’t tell the difference, but there
is a genuine difference.
Thick vs. Thin Illusions
But this doesn’t help!
According to Tom all the demon has done is get rid of things he
can sense in this special way.
He hasn’t gotten rid of
flowers
because flowers are just things
that look, smell, taste and feel a certain way!
Two Interpretations
There are two ways of trying to make sense of Bouwsma’s
remarks:
(1)
Linguistic Interpretation
(2)
Metaphysical Interpretation
Bouwsma’s Argument: Linguistic
Interpretation
Our word “flower” means something different than the demon
thinks.
The word “flower” just means something that looks, smells,
tastes and feels a certain way.
So if the demon means to use our word “flower” when he
says “There are no flowers” what he says is false.
So Tom is not deceived.
On the Linguistic Interpretation
What we mean by “flower” is clearly not just some set of
observable characteristics:
Flowers have a wide range of these (colors shapes, tastes,
etc.) and we call them all “flowers.”
We can imagine discovering a new plant that did not have
these observable characteristics that we would call a “flower.”
On the Linguistic Interpretation
What about Milly?
When Tom talks about Milly, he doesn’t mean “some person
or other with certain characteristics.”
He uses the word “Milly” to refer to
Milly
, not some identical
duplicate or clone.
On the Linguistic Interpretation
Someone is deceived just in case the world is different than
they believe it to be.
Whatever Tom would
call
“a flower” or call “Milly” seems
entirely irrelevant to the question of whether or not flowers or
Milly exist!
Bouwsma’s Argument:
Metaphysical Interpretation
Flowers
just are
things that looks, smell, taste and feel a
certain way.
What it is
to be a flower
is exhausted by its observable
characteristics.
So the demon has not created a world in which there are no
flowers, because there are things with those observable
characteristics.
So Tom is not deceived because all his ordinary beliefs are
true.
On the Metaphysical Interpretation
Things can have all the observable characteristics of flowers,
but not be flowers
What it is to be a flower probably involves a certain kind of
evolutionary history that is not directly observable.
On the Metaphysical Interpretation
What about Milly? Things are even worse!
According to the story, the demon
destroys
Milly, but Tom still
experiences something that looks, feels, smells and acts like
Milly.
On the Metaphysical Interpretation
What if someone destroyed your partner or someone else
close to you and replaced them with a perfect duplicate?
Would you be at all inclined to say that the duplicate was
the
same person
?
The Experience Machine
We don’t just care about what we can experience (i.e. what is
observable) we also care deeply that the world actually is the
way it appears to be.
The Experience Machine
“Suppose there were an experience machine that would give
you any experience you desire. Superduper
neuropsychologists could stimulate your brain so that you
would think and feel you were writing a great novel, or making
a friend, or reading an interesting book. All the time you would
be floating in a tank, with electrodes attached to your brain.
Should you plug into this machine for life, preprogramming your
life’s experiences?” (Nozick:
Anarchy, State and Utopia,
81)
The Experience Machine
Whatever you want in your life, the experience machine can
be programmed to give you experiences of doing that very
thing.
Of course, you aren’t
actually
doing it. You are sitting in a
vat!
Would you plug in?
Summation
What all of this shows is that Bouwsma is simply wrong about
his diagnosis of the evil demon case.
Summation
The correct description of the case is to say that Tom
thinks
that the world is a certain way (that it has water, flowers, and
Milly), but that the world is not that way.
In other words, he is deceived, just as Descartes assumed.
Explore Bouwsma's philosophical insights on illusions and reality through scenarios involving an evil demon and a deceptive world. Learn how individuals can distinguish between illusion and reality in thought experiments involving deception and perception.
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Presentation Transcript
Bouwsma and the evil demon
Bouwsmas Goal Bouwsma tries to show that in the evil demon scenario we are not actually deceived. Contrary to what Descartes assumed, in such a world all of our ordinary beliefs are still true!
Demon vs. Tom Round 1: Paper World While Tom sleeps the demon replaces everything in the world with paper. Tom, though fooled (visually) at first, is easily able to uncover the illusion by using his other senses.
Demon vs. Tom Round 1: Paper World Bouwsma draws two lessons from this case. First: An illusion is something that looks like or sounds like, so much like, something else that you either mistake it for something else, or you can easily understand how someone might come to do this. (117)
Demon vs. Tom Round 1: Paper World Second, an illusion requires that the deceived can tell the difference between the illusion and reality. This does not mean that one cannot be deceived by an illusion, but one must be able to understand the difference between the two (e.g. paper world vs. actual world).
Announcements My office hours this week are cancelled for tomorrow. I will hold my office hours on Friday from 11AM-1PM. Thomson has been postponed again!
Tom vs. the Demon Round 2: Demon World While Tom sleep the demon destroys everything besides Tom and makes it so that Tom will continue to think that everything is just as it was yesterday.
Tom vs. the Demon Round 2: Demon World There are to be no flowers, no Milly, no paper. There is to be nothing at all, but Tom is every moment to go on mistaking nothing for something, nothing at all for flowers, nothing at all for Milly, etc And yet all is to be arranged in such a way that Tom will go on just as we now do He will love flowers, he will kiss Milly, he will blink at the sun. So he thinks (119)
Tom vs. the Demon Round 2: Demon World In this case there is no way, even in principle for Tom to detect the change. All his perceptual experiences are identical to what they were before. This is just like our cases of radical deception (Matrix/BIV/Evil Demon)
Tom vs. the Demon Round 2: Demon World In Bouwsma s story the Demon attempts to explain to Tom the nature of his deception. In response Tom claims that by flower he just means thing that smells, feels, looks, etc. this way. According to this line of thinking, the demon has not created a world in which there are no flowers and Tom is not deceived!
Thick vs. Thin Illusions Thin Illusion: e.g. lowers in a mirror and paper flowers; they only look like flowers. They do not have all of the qualities a flower has. Thick Illusion: A demon flower. Mirrors all the properties of a flower. It looks, feels, smells, tastes, etc. like a flower.
Thick vs. Thin Illusions Tom s reply: I see that what you mean by thin illusion is what I mean by illusions, and what you mean by thick illusions is what I mean by flowers. So when you say that my flowers are your thick illusions this doesn t bother me. And as for your mirror that mirrors all layers of your thick illusions, I shouldn t call that a mirror at all. It s a duplicator. (78)
Thick vs. Thin Illusions The demon replies that HE has a sense by which he can tell real flowers from demon flowers: (thick illusions from reality). Tom lacks this sense, so he can t tell the difference, but there is a genuine difference.
Thick vs. Thin Illusions But this doesn t help! According to Tom all the demon has done is get rid of things he can sense in this special way. He hasn t gotten rid of flowers because flowers are just things that look, smell, taste and feel a certain way!
Two Interpretations There are two ways of trying to make sense of Bouwsma s remarks: (1) Linguistic Interpretation (2) Metaphysical Interpretation
Bouwsmas Argument: Linguistic Interpretation Our word flower means something different than the demon thinks. The word flower just means something that looks, smells, tastes and feels a certain way. So if the demon means to use our word flower when he says There are no flowers what he says is false. So Tom is not deceived.
On the Linguistic Interpretation What we mean by flower is clearly not just some set of observable characteristics: Flowers have a wide range of these (colors shapes, tastes, etc.) and we call them all flowers. We can imagine discovering a new plant that did not have these observable characteristics that we would call a flower.
On the Linguistic Interpretation What about Milly? When Tom talks about Milly, he doesn t mean some person or other with certain characteristics. He uses the word Milly to refer to Milly, not some identical duplicate or clone.
On the Linguistic Interpretation Someone is deceived just in case the world is different than they believe it to be. Whatever Tom would call a flower or call Milly seems entirely irrelevant to the question of whether or not flowers or Milly exist!
Bouwsmas Argument: Metaphysical Interpretation Flowers just are things that looks, smell, taste and feel a certain way. What it is to be a flower is exhausted by its observable characteristics. So the demon has not created a world in which there are no flowers, because there are things with those observable characteristics. So Tom is not deceived because all his ordinary beliefs are true.
On the Metaphysical Interpretation Things can have all the observable characteristics of flowers, but not be flowers What it is to be a flower probably involves a certain kind of evolutionary history that is not directly observable.
On the Metaphysical Interpretation What about Milly? Things are even worse! According to the story, the demon destroys Milly, but Tom still experiences something that looks, feels, smells and acts like Milly.
On the Metaphysical Interpretation What if someone destroyed your partner or someone else close to you and replaced them with a perfect duplicate? Would you be at all inclined to say that the duplicate was the same person?
The Experience Machine We don t just care about what we can experience (i.e. what is observable) we also care deeply that the world actually is the way it appears to be.
The Experience Machine Suppose there were an experience machine that would give you any experience you desire. Superduper neuropsychologists could stimulate your brain so that you would think and feel you were writing a great novel, or making a friend, or reading an interesting book. All the time you would be floating in a tank, with electrodes attached to your brain. Should you plug into this machine for life, preprogramming your life s experiences? (Nozick: Anarchy, State and Utopia, 81)
The Experience Machine Whatever you want in your life, the experience machine can be programmed to give you experiences of doing that very thing. Of course, you aren t actually doing it. You are sitting in a vat! Would you plug in?
Summation What all of this shows is that Bouwsma is simply wrong about his diagnosis of the evil demon case.
Summation The correct description of the case is to say that Tom thinks that the world is a certain way (that it has water, flowers, and Milly), but that the world is not that way. In other words, he is deceived, just as Descartes assumed.
