David Makinster again,
and this lecture
is called What is Truth?
This corresponds to the assigned
readings in Bertrand Russell's
The Problems of Philosophy.
It sort of dovetails with
the previous lectures
that are based on that book.
But like those
lectures, it's also
going to go a little farther.
Very famously, in
the New Testament,
Jesus is being interrogated
by Pontius Pilate.
And Jesus says something
about coming into the world
to bear testimony to the truth.
And Pilate replies,
what it is truth?
Which all of the Romans seem to
think is a really funny joke.
Why would they think that?
These are classically
educated pagans, these Romans,
Pontius Pilate and his cohorts.
And of course what
he's doing is,
interestingly enough, he's sort
of doing something Socratic.
But what is truth?
Oh lord, no, he's going
to do like Socrates.
Which Jesus doesn't
answer, although that
would have been an
interesting conversation.
But this is a
question which always
reminds me of what Saint
Augustine said about time.
Of course I know what
time is, unless you
ask me to explain it.
And then I'm at a complete loss.
Most people feel the
same way about truth.
Well, if you ask, what is truth?
Well, you know, it's like
stuff that's not false.
Well, isn't that circular?
And indeed, Russell does
say that any adequate theory
of truth must also have
an account of falsehood.
Plato dedicated
an entire dialogue
to understanding the
nature of falsehood.
It's called the Sophist.
Russell talks about primarily
the correspondence theory
of truth, the coherence
theory of truth,
and then talks about
the pragmatic theory
of truth just enough
to dismiss it.
And we're going to try to
give it a little better, more
sympathetic treatment here.
He also talks about knowledge
by acquaintance and knowledge
by description.
And I'm going to try
to show that it's
the commitment of Russell to a
correspondence theory of truth
that really requires him
to make this distinction
and to press hard
with this distinction.
Also going to talk about a
contemporary problem, a gate
through which you must pass if
you study philosophical truth,
called the Gettier problem
after the philosopher
who articulated it.
And we'll talk about
the possibility
that maybe we need a sense
of truth that isn't merely
about propositions.
Traditionally, Western
philosophers at least
have wanted to
define truth as being
a property of propositions.
Statements are true or false.
Anything that's not
verbal, not linguistic,
is not capable of being
meaningfully called
true or false.
So let's begin.
The correspondence
theory of truth
is very often thought of as
the default theory of truth.
If you don't think
too much about it,
it's probably what
you come up with.
And indeed, it does
seem to be intuitive.
It does seem to work well
for many instances of things
that we'd say are true.
OK, the pen is on my hand.
There's a statement.
The pen is on my hand.
Is that true?
Well, actually
marker, OK, I know
someone will say, wait a minute.
He's trying to fool us.
That's not a pen.
That's a marker.
OK, the marker is on my hand.
Is that true?
Well, not a trick
question, yeah, it's true.
What makes it true?
Well, according to the
correspondence theory of truth,
this state of affairs
makes it true.
Not another proposition about
the world, but the fact that
the state of affairs exists.
The marker is on my hand.
What makes that false?
Well, here's the marker.
Here's my hand.
That's the state of the world.
As long as you're dealing with
what British philosophers like
to call medium size dry
goods as your examples,
that seems to work pretty well.
Plato talks about the
correspondence theory
of truth and dialogue
called the Theaetetus,
and he commends it
as seeming to be
very intuitive and
straightforward
for a number of instances of
how we use the term truth.
But he also raises
doubts that it's
completely adequate for every
way in which we use truth.
Remember, Plato is one
of those people saying,
we don't necessarily
always mean the same thing
when we say that
something is true.
For propositions about
the way the world
is, such as the pen is on
my hand, ordinary material
objects, that seems like it
would be pretty adequate,
except for one thing.
What does correspondence mean?
How exactly does a
proposition correspond
to something in the world?
Now, that would seem
to be relatively
easy to explain until
you try to explain it.
And then in fact it's been
devilishly difficult for people
to come up with an explanation
of that that actually holds up
to scrutiny.
Some contemporary philosophers,
defending the correspondence
theory of truth,
have said, look,
in any system you have certain
terms that are primitives.
I believe I mentioned
those before.
A primitive, whether it's
in mathematics, or logic,
or whatever, is
a first principle
that isn't defined in terms
of more basic principles.
It's a term that is in fact
defined by the way it's used.
You have to have some
things that are undefined.
Otherwise you get into
an infinite regress
of definitions.
Well, define what
correspondence is.
Well, define what you're talking
about in that definition.
OK, now define
what you're talking
about in that definition.
And you can go on and on and on.
It's an infinite regress.
Something has to be taken
as a starting point.
And then you
understand what it's
supposed to mean by
demonstrating how it's used.
Correspondence is good
for ordinary objects,
but what about abstract
general propositions?
One plus one equals two.
What does that correspond to?
Now, that's a little bit
more difficult to explain
in terms of correspondence.
If P then Q, and P therefore Q.
OK, you've seen that
argument form before,
although I just
wrote it in notation.
What does that correspond to?
There's no single
state of affairs
that either one of
these corresponds to.
Because of that,
some philosophers
have been unwilling to
accept the correspondence
theory of truth as being
either robust enough to explain
everything that we
need to explain,
and some have rejected
it all together and said,
this is an example that breaks
the back of the correspondence
theory.
Now for Plato and for
Russell, by the way,
this is not a
particular difficulty
if you believe that abstract
general properties exist,
universals, in other
words, that universals
are a real part of the world.
Abstract general
properties, OK, that's
what these correspond to.
OK, but if you want a
more trim metaphysics,
if you're not willing to embrace
the notion of universals,
then there doesn't seem
to be anything really
for these kinds of
truths to correspond to.
Now, out of that concern came
the coherence theory of truth.
Coherence means that
things hold together.
They make a sensible,
intelligible whole
when taken together.
The coherence theory
suggests that in fact there
are certain fundamental
beliefs that we
use to understand the world.
What makes a proposition
true or false
is whether or not it is coherent
within that set of beliefs.
Some philosophers
that what to say it's
within a set of
a priori beliefs.
And some would say, we don't
need to even go that far.
It's just here are the
working assumptions
we use to get through the world.
We call something
true if, in fact,
it is coherent within
that set of beliefs.
Now, that seems to
work fairly well
for general abstract
propositions such as these.
But if you want
to explain in what
sense it's true that the
marker is on my hand,
all of a sudden this
gets extremely awkward.
You have to start
saying, well, we're
invoking these a priori beliefs
about space, time, causality,
sensation, blah, blah,
blah, blah, blah, blah,
and building a fairly elaborate
and increasingly less plausible
edifice to explain a
proposition such as the marker
is in my hand in
terms of coherence.
So the mirror images
of one another,
correspondence seems
to work pretty well
for ordinary objects.
And unless you have a
platonic or Russellian sort
of metaphysics, it doesn't
seem to work as well
for abstract propositions.
Coherence seems to work pretty
well for abstract propositions.
But if you try to use it
for everyday propositions
about the world, it
gets very clunky, and is
isn't clear that it's
really working very well.
Russell also points out
an additional criticism,
which is still debated.
Why can't you have several
different sets of beliefs
and say a proposition
is in fact coherent
within that set of beliefs?
Several internally
coherent but incompatible
sets of beliefs about the world.
Normally we'd say,
well, if you have
completely different and
incompatible explanations
about how the world is,
either one or both of you
is wrong on at
least some respects.
To say we have
different beliefs is not
to say that there
are two truths.
It's to say some of us have
got an accurate understanding,
and some of us have got a
less accurate understanding.
Or some parts of each
understanding are accurate,
and others are inaccurate.
The notion that people have
different sets of beliefs
doesn't indicate that truth
is, in any significant sense,
plural.
Beliefs are plural.
But I'm perfectly
capable of having
false beliefs, as
is anyone else.
You wouldn't
conclude that if you
say two different societies
have different beliefs
about the shape
of the world, you
wouldn't conclude from that
that the world has no shape.
Because in fact there isn't
any truth to the matter.
There's just conflicting
sets of beliefs.
Well, the logic would be the
same to say here that, well,
if you have two different sets
of beliefs and each of them
works reasonably well
or reasonably faultily,
imperfectly to explain the
world that both of them
are equally true.
Different explanations
can be more or less wrong.
That's the beauty of the
rise of modern science
is saying, as Socrates
said, make your hypotheses.
Hold it up to scrutiny.
Test it out.
And if it works, good.
If it doesn't work, you're
going to have to revise it.
And if you can't revise
it to make it work,
you don't get to cherry
pick your evidence.
You don't get to suspend logic.
You have to abandon
your hypotheses
if you can't make it
work in terms of the way
the world is actually
presented to us.
Now, on the other
hand, you think
about the parable of
the seven blind wise men
and the elephant, is
any one of them wrong?
Well, as the seventh
blind wise man said,
they're all speaking
the truth insofar
as they're telling
you their experience.
But they are all
speaking falsely
insofar as they think that
that's the whole story.
And in fact you might go further
and say every one of them
is speaking falsely.
The one who said, the elephant
is like a great serpent
because he felt the trunk would
have been more accurate to say,
the elephant, the part of
the elephant that I touched,
seemed to feel like
a great serpent.
I have no other
reason for believing
it actually is a serpent.
Well, the part of the
elephant I touched
seemed had these characteristics
in common with a great tree
trunk.
But it would be hasty to
conclude that it actually
is a tree trunk, and
so forth, and so forth.
In other words, the more
cautious and the more careful
we are about how we describe
the world, the less likely
we are to rush into judgments
that later can't be defended.
OK, finally the pragmatic
theory of truth.
And Russell wants to
dismiss that right away.
Basically pragma, the
notion of pragmatic,
comes from an ancient
Greek term, pragma,
which means significant work.
Pragmatism as an American
school of philosophy.
It's not pragmatism in
the sense that we use it
in ordinary language
as in, well,
my values don't enter into it.
I'm just concerned
about what works.
Pragmatism is a
theory of meaning.
And essentially what it
says is that language
is a tool kit, not a
tool but a tool kit.
It's a bunch of tools
clumped together.
And we use it for a bunch
of different purposes.
And the truth of a
proposition depends upon
whether in fact it is
functionally adequate.
Does it in fact
achieve whatever it
is that caused us to utter it?
If I say, the pen is on my hand,
why would I be saying that?
So that you can locate the pen.
If I say that, does it in fact
help people locate the pen?
Yes, OK, well, it succeeds.
That's why we call it true.
If I say, the house is on
fire, and in fact nobody
can find any fire in the
house, was that true?
No, that's false.
Why?
Because if I say
that, apparently I'm
trying to say that you're
going to find flames somewhere
smoldering, smoking, that
it's dangerous to stay inside
or whatever.
But what if nobody can
find anything like that?
Well then why was I saying it?
OK, there's falsehood for you.
I'm muttering something
that doesn't really
have the purpose that
it pretends to have.
Russell thinks this is nonsense.
And he thinks it's nonsense
because he says, of course,
you have to be able to
distinguish between truth
and falsehood in any
adequate theory of truth.
And the problem with saying
that a proposition is true
if it achieves its end is that
you can't really clearly state
what the difference is between
a successful lie and the truth.
If I say, for instance,
Santa Claus is coming,
and he won't come unless
you're in bed asleep,
I might be able to get a child
to hop in bed and go to sleep.
And that's my purpose.
OK, so I achieved my purpose.
Does that mean that it's true
that Santa Claus is coming?
Bertrand Russell was
actually rather fond
of using that sort of
Santa Claus example of how
it is a proposition may
be successful in its aims
even if it is not
true in the sense
that we want it to be
true as in presenting
this is the way the world
is rather than telling us
something about a world
that doesn't exist
and getting us to do
something because of that.
I saw an editorial
cartoon a couple of years
ago, Socrates talking
the Karl Rove.
Socrates had his
head in his hand.
And Karl Rove was saying
to him, but Socrates,
if a lie is repeated so
often that it is believed,
does it not become the truth?
OK, now that's exactly what
Russell is worried about.
You can skillfully mislead
people and achieve your end.
And as Russell sees it, the
pragmatic theory of truth
cannot distinguish between
doing that and actually telling
the truth.
Now, there's a sense in which
this notion of, OK, well, you
test your propositions
by whether they have
the effects you
want, there's a sense
in which that is sometime
certainly useful.
People who say daily
affirmations, of course,
to try to improve their attitude
and hence improve their lives,
is it working?
Do you feel better
about yourself?
Do you treat people better?
Well, there's a
sense in which there
is some sort of truth contained.
Not because it's
describing the world
but because it is promising
to have an effect,
and it's having that effect.
Very often with
ethical precepts,
and I think this is
very close actually
to David Hume's
view about ethics.
Ethical precepts
are supposed to help
us make life a certain way.
The value or lack of value
of an ethical precept
is to be understood in terms
of how it does or does not
improve our lives.
So the sense of ethical
truth would simply be,
does this work?
We utter ethical
propositions in order
to alter our behavior alter
the behavior of others
in a way that makes life better.
Does it work?
Well, in that sense
it's an ethical truth,
because ethical truths aren't
about matters of material fact
or matters of logical
or mathematical fact.
So there may be a sense
in which this is actually
a very useful way of looking
at at least some propositions.
Russell is committed
to a distinction,
and he has a whole
chapter by itself
on this, between knowledge
by acquaintance and knowledge
by description.
And as I said at the
beginning, his commitment
to the correspondence
theory of truth
really requires this of him.
Knowledge by description
is essentially knowledge
through language, just
what it sounds like.
Knowledge by
acquaintance means that I
am directly aware of something.
Russell spilled a lot of
ink talking in various books
and articles about the
implications of that.
Do I see a marker?
No, I see colors.
I see shapes.
I see relationships
between them, or at least
intellectually apprehend
relationships between them.
I infer there's a pen here.
OK, so what am I
acquainted with?
Things like colors, shapes,
textures, sense data,
internal states, such
as pain or pleasure.
That's what I'm acquainted with.
When I start inferring
anything about that,
when I start laying
descriptions on those things--
this is a pen.
I have a headache.
Whatever-- when I'm describing
it, when I'm saying,
this is the proper language to
describe what I'm experiencing,
at that point I
have opened the door
to the possibility of error.
In fact, the further away
from acquaintance I get,
the more elaborate my
descriptions become,
the more the chance of error.
That's a distinction that Rene
Descartes also worried about.
My direct experience is,
as he put it, incorrigible.
It can neither be
improved or made worse.
It just is what it is.
But when I start trying to talk
about it, and say what it is,
and communicate it
to other people,
I'm adding descriptions.
I'm saying, this language
rather than this language
is appropriate.
And at that point, I'm
capable of committing error.
Now, the dilemma is the
closer we are to acquaintance,
the less useful it is.
Because we can't communicate it.
The farther away
from acquaintance
and into description
we get, the more useful
it becomes, but also the greater
the possibility of error.
And Russell does
talk about this.
He notes the elaborateness
of description,
which is necessary
for everyday life.
It's necessary for
science, whatever.
The elaborateness
of the description
increases the
possibility of error.
Now, how is that related to the
correspondence theory of truth?
Every description
we have of the world
has to do more than
simply be logically
consistent or consistent
either with other propositions.
Somehow, it has to drill
down to a direct acquaintance
with the world.
It has to be about what
we really experience.
That's his reason for
making so much out of this.
It's got to be about something.
And it can't just be
about other language.
Wittgenstein I'm
mentioning again.
Wittgenstein once said to
his students at Oxford,
he wrote on the board, this
is a very pleasant pineapple.
And he said, what
does this mean?
And his students
replied, uh, this
is a very pleasant pineapple.
Well, where does the
meaning comes from?
From a thought.
From a thought?
Yeah, what's the thought?
The thought is, this is a
very pleasant pineapple.
Well, wait a minute, where
does the meaning of the thought
come from?
What is this business
about the language
is referring to a thought?
Isn't the language referring
to expressing an experience
that I'm having?
Why do you need that
additional layer in between?
Language has got to
be about something.
Plato himself, long ago, 2,500
years before Wittgenstein,
said that language has to
arise out of life in order
to have any purpose in life.
Wittgenstein says
something very similar.
Language arises out
of forms of life
and expresses forms of life.
Russell is by no means
expressing the same thing
that Wittgenstein
was expressing.
But he is saying something
that is, if you will,
parallel, namely,
description has
to be based on acquaintance
because our language has
to be about something.
It has to actually
point to something.
The map is not the world.
But that doesn't mean
I can just sit down
and doodle and say,
OK, here's a map.
The map has to actually
point to something.
Again, this is something
Wittgenstein said.
Some of our language
says something.
Some of our language,
on the other hand,
merely points to something.
There's a Japanese parable
that this is actually
about religion, but religion is
a finger pointing to the moon,
and we're all untrained dogs.
How Zen, huh?
OK, what does that mean?
Religion is a finger
pointing to the moon,
and we're all untrained dogs.
For our purposes, we could
say instead of religion,
we could say language.
Language is a finger
pointing to the moon,
and we are all untrained dogs.
Have you ever tried to
get an untrained dog
to look at something?
Look, Rover, look, look, look.
What's Rover going to look at?
Your finger, because
that's what's moving.
He doesn't understand
the concept of pointing.
And the Zen parable is saying
that religion, language,
whatever, this is what we do.
We end up staring at the finger
that's doing the pointing
instead of looking at what
it was trying to point to.
A part of what
Wittgenstein is saying
is you have to look at what
the finger is pointing to.
And indeed Russell is
saying, you know what?
Language doesn't mean
anything unless it's
a finger pointing to something.
While we're on the
subject of truth,
I just want to briefly bring
up something called the Gettier
problem, named after the
philosopher who proposed
it just to get you to
think a little bit more
about how slippery the
notion of truth can be.
There's a principle
called addition in logic.
If A is true, I can add
anything else to it,
and that compound
proposition is true.
A or B, OK?
I'll just, since we haven't
really learned notation,
I'll just put in the word or.
A or B, if A is true, then the
compound proposition A or B
is true regardless of what B is.
My name is David, or
I'm a monkey's uncle.
OK, is that proposition true?
Yeah.
Obama is president--
I'm still using
this lecture in a
few years, just note
that I'm doing this in 2013.
Obama is president, or
I'm king of the world.
OK, we actually use
propositions like that.
So here's the problem.
Let's say my co-worker,
Henderson, has
got a very distinct car, let's
say a bright yellow 1952 Buick.
You're not likely to see
a lot of those around.
Every day, I look
out of my window,
and I see there is that
bright yellow 1952 Buick.
And I think, oh,
Henderson's here.
Now, let's say that
Henderson goes on vacation
and I don't know about it.
And he goes to Barcelona.
Oh, let's make it
even more elaborate.
Let's say he goes to Timbuktu.
Timbuktu is a town in
Mali, the African nation.
Let's say he goes to Timbuktu,
always wanted to go to Mali.
Now, someone comes in and
says, is Henderson here?
And I look out in
the parking lot,
and there's a yellow 1952 Buick.
It may not be his.
He may have loaned
it to a co-worker
while he's away in Timbuktu.
And the person who asked me the
question, I say to that person,
well, yeah he's here.
Are you sure he's here?
I can't find him.
Are you sure
Henderson's here today?
I look out.
I see the car again.
I say, look, Henderson's
here, or he's in Timbuktu.
And I mean that as
sort of a joke, right?
Now actually it's true.
Henderson's not there.
He's in Timbuktu.
I thought that
this part was true,
so I added something
implausible to it for contrast.
It turns out this
is what's true,
and this is not what's true.
So OK, one traditional way
of looking at knowledge
is that knowledge is
justified true belief.
I have a belief.
The belief is true.
And I can give an account of it.
OK, well, I have a
belief Henderson's here
or he's in Timbuktu.
I have a justification.
I see his car.
That's good inductive reasoning
for believing he's here.
Plus this principle of deductive
addition, I can add anything
I like to it.
So if Henderson's here is
true, then Henderson's here
or he's in Timbuktu is true.
It's a justified true belief.
But the problem is, the part
of it that I think is true
is not true.
The part of it that I thought
was implausible is true.
My justification is actually
for the part that's not true.
Oh, OK, head spinning
a little bit?
Well, the whole point of this
is Gettier's pointing out
the notion of truth is a
lot more slippery than we
might take for granted.
OK?
We want to start investing
the nature of truth,
we have to understand that
there are a lot of ways
that we can go
astray, that we can
misunderstand the
nature of true.
Now, I want to add one more
thing that I think is important
and just want you
to consider this.
All these theories of
truth have pretty much
made propositions, or
statements if you will.
Language, the bearer of truth.
Most people who are artists, at
least most of the artists I've
known, would claim,
you know what?
In my music, or in my painting,
or in my dance, or whatever,
I feel like I am grasping
certain truths that
can't be expressed
linguistically.
And I'm conveying them the only
way that they can be conveyed.
Are there
non-propositional truths?
Well, none of these
approaches actually
do very good job of accounting
for non-propositional truth.
It may be, it
[inaudible] essentially
taken our cue from Plato
that we don't necessarily
mean the same thing every
time we say something is true.
It may be that each of
these traditional approaches
works pretty well but for
different instances, that truth
isn't one thing.
That it's maybe a
bunch of things.
And if it's a bunch
of things, then
maybe there's such a thing
as non-propositional truth
as well.
In fact, wouldn't there have
to be non-propositional truths
for knowledge by description to
be about something that's true?
People sometimes don't
want to use the word true
when they're talking
acquaintance.
They say, OK, well, rather
than truths by acquaintance,
we want to say that we know
something by acquaintance.
It's not truth.
It's a fact.
It's not something
that's linguistic.
But I think there's something to
be gained, perhaps, by asking,
should we in fact expand
the notion of truth
so that it includes things that
are in fact not linguistic?
It's not just language
that can be true or false.
OK?
