[MUSIC PLAYING]
When the term modern philosophy is used in
universities, it's usually to make a distinction
from ancient and medieval philosophy.
So it doesn't mean just the philosophy of
our own day, here in the 20th century, it
means the philosophy of the last four centuries.
In fact, there's one man who is generally,
and I think rightly, regarded as the inaugurator
of modern philosophy-- the Frenchman Descartes.
So in practice, what the term modern philosophy
means is, philosophy from Descartes on.
Rene Descartes was born in France in 1596.
He received an unusually good education.
But he also had unusual independence of mind.
And while still young, he perceived that the
various authorities he was studying quite
often put forth arguments that were invalid.
As a young man, he became a soldier and traveled
widely in Europe, though without seeing any
fighting.
And he was struck by the fact that the world
of practical life was as full of contradictions
as the world of books.
He became fascinated by the question whether
there was any way at all in which we human
beings could get to know anything for certain.
And if so, how.
He stopped travelling and went into seclusion
in Holland, the country in which intellectual
life in those days was at its freest.
There, during the 20 years from 1629 to 1649,
he produced work of the profoundest originality
in mathematics and philosophy.
And also did a great deal of work in science.
He invented the branch of mathematics known
as coordinate geometry.
It was his idea to measure the position of
a point by its distance from two fixed lines.
So every time we look at a graph, we're looking
at something invented by Descartes.
In fact, those two familiar lines on a graph
and known by his name.
They are called Cartesian coordinates, Cartesian
being the adjective from the name Descartes.
His most famous works of philosophy are The
Discourse on the Method, which was published
in 1637, and The Meditations, published in
1642.
He never married, though he had an illegitimate
daughter who died at the age of five.
He always had an eye to his own dress.
Was proud of being an officer.
And on the whole, preferred the company of
men of affairs to that of scholars.
But during the years of his creative work,
he lived a very solitary life.
When he was 54, he was prevailed on by Queen
Christina of Sweden, rather against his will,
to go to Stockholm and become her tutor in
philosophy.
It was a mistake.
In the bitter Swedish winter, he succumbed
to pneumonia and he died in the following
year, 1650.
With me to discuss the work of this first
of modern philosophers is the provost of King's
College, Cambridge, Sir Bernard Williams,
author of a well-known book on Descartes.
Bernard Williams, I think the best way we
can begin is try and get clear in our minds,
what it was that Descartes thought was the
main problem he was going to have to confront
when he started.
Now, what was that?
I think he'd been impressed by the education
you referred to, and his experience and life
around it.
With the idea that there was no certain way
of acquiring knowledge.
It looked as if there were some sorts of knowledge
around, but there was no reliable method by
which people could advance knowledge.
I think it's very important to put it in historical
context that one realizes that science, in
our sense, really didn't exist.
I mean the concept of science in our sense
is an organized international enterprise,
with research methods and laboratories and
all that, simply didn't exist.
And there was room for an enormous range of
opinions about what chances there might be
of ever being on a science, ever being a science.
On the one hand, there were people-- and perfectly
sensible people-- who thought that if you
just found the right fundamental method, you
could solve all the fundamental problems of
understanding nature in a very short while.
For instance, Francis Bacon, the English statesman,
thought that you'd be able to get everything
on the right road in a very brief period.
On the other hand, there were people-- skeptical
people-- who thought you couldn't find any
knowledge at all.
That there wasn't going to be any knowledge.
That everything was up for grabs, as it were.
I think one particular reason-- it's quite
important actually-- why there was so much
skepticism around, was actually a result from
Religious Reformation.
That after the Religious Reformation, there
were all sorts of claims made about how you
found out religious truth.
And they all conflicted with one another and
there was no way of deciding between them.
And that gave rise to tremendous amount of
controversy in which people said, the enemies
of all religions said, well there simply isn't
a way of solving any of these questions.
All these people disagree with each other.
You can't put on a foundation.
And then religious people, sort of reacting
against that in turn said, well, religion's
no different in this or anything else.
There isn't a way of putting anything on a
firm foundation.
So that skepticism was quite an important
current in the intellectual climate of Descartes'
time, co-existing in an odd way with very
extravagant hopes of what science might be
able to do.
And for instance might be able to do for mankind,
through what we would now call technology.
For instance, there were great hopes that
there could be a scientific medicine and scientific
industry, and so on.
But nobody quite knew how to do it.
For a fundamental innovator like Descartes,
the institutional set-up must have presented
problems, too, musn't it?
I mean almost every serious institution of
learning, or study, or teaching was in the
hands of an authoritarian church, whose own
intellectual leaders were for the most part
enthralled through ancient authority.
That is certainly true.
Of course there were many different religious
influences, as we just said.
I mean that one effect of the Reformation
had been that some seats of learning had more
of a Protestant complexion, while obviously
those in Descartes' own Paris had a Catholic
complexion, and so on.
Because the point you mentioned about authority
is very important.
Although there had been a good deal of research
into what we would now call mechanics, or
kind of mathematical physics in the Middle
Ages, and we shouldn't forget that fact.
A great deal of what would go by the way of
being science was actually in the form of
commentary on ancient books.
Above all, though not exclusively those, of
Aristotle.
One thing that Descartes and others of his
generation absolutely knew, was that historical
authority was not the same thing as if it
were first order research, or inquiry.
In other words, what one can say is that Descartes,
in starting out on his famous search for certain
knowledge, was really looking for a way of
moving forward from the situation that you've
just outlined.
I mean he was looking for a research program,
as we might say in modern parlance.
And prior to that, a research method.
Yes, I think that's a perfectly correct description
of the situation.
It's very important, with one further fact
which conditions all of his work and which
one finds the thread through it, was that
science was not conceived as a shared, or
joint, or organized enterprise, as it is now.
For us, it's just taken for granted that science
means scientists.
There a lot of people.
And they communicate with each other.
And there's a division of labor, a division
of intellectual labor.
At that time, in the first half the 17th Century,
it was still a reasonable project for one
man to have the idea that he could lay the
foundations of all future science.
Descartes, who did really fundamentally believe
that, it was not, as it were, a piece of megalomaniac
insanity on his part, as is it would be in
the modern world for anybody to have that
idea.
In my introduction to this discussion, I said
that Descartes became fascinated by the question
of whether there was anything that we could
know for certain.
He was clear from the outset, wasn't he, that
certainty and truth are not the same thing.
And that they-- to put it at its utter-most
crudity-- certainty is a state of mind.
That truth relates to the way things are out
there in the world.
But he seems to have thought that you could
only be-- know that you've got the truth,
so to speak, if you also had grounds for certainty.
So that his method was not only going to have
to be one which delivered the goods in the
form of worthwhile conclusions, but also gave
him a way of defending them against skeptical
arguments.
Now, how did he go about meeting that double-barreled
requirement?
Well Descartes had a set of conditions on
inquiry.
And some of them were just sort of sensible
rules about dividing questions up into handleable
amounts, trying to get your ideas clear and
things like that.
But he had got this very characteristic, and
important rule for him, that you shouldn't
accept as true anything about which you could
entertain the slightest doubt.
Now, of course as you said, on the face of
it that isn't in immediately sensible rule.
Because in ordinary life, we are constantly
seeking true beliefs about things but we don't
necessarily want to make those beliefs as
certain as possible.
For one thing, we'd have to invest too much
effort into making the ultimately certain
beliefs all the time.
But Descartes, who was trying to get the foundations
of science, and also not only the foundations
of the science itself in the sense of fundamental
general truths about the world, but also to
lay the foundations of inquiry.
That is, to be able as he thought, to lay
the foundations of the possibility of going
on to find out more things.
To establish that scientific knowledge was
actually possible.
For him, he felt that it was absolutely essential
that you should start the search the truth
with the search for certainty.
But what he wanted to do was to be able to
put the scientific enterprise, as we would
put it, into a shape in which it could no
longer be attacked by skeptics.
So the first thing he wanted to do was to
engage in the kind-- we might call it pre-emptive
skepticism.
In order to put the foundations of knowledge
beyond skeptical reach, he said to himself,
I will do everything the skeptics can do,
only better.
And what I can do by pressing the skeptical
inquiry hard enough, is, he hoped, come out
the other side with something which would
be absolutely foundational and rock hard.
And among the most characteristic features
of Descartes is not that he confuses the idea
of looking the truth, the idea of looking
for certainty, he saw they were two separate
things.
But he thought that the only sure way of searching
for truth was by starting by searching for
certainty.
And that led him, didn't it, to the famous
Cartesian doubt.
Yes.
As a method.
Not the discourse on the method.
That's about something else, but doubt used
as a method was fundamentally his message.
Yes, he adopted something that he called the
method of doubt.
And indeed, the method of doubt is part of
the method which is discussed in the discourse
on the method, but only one element in it.
That's the situation there.
Now the method of doubt worked, since he was
looking for certainty, by laying aside anything
in which he could find a doubt.
As he famously put at one point, it's like
having a barrel of apples and some of them
are bad and some of them are sound.
You want to keep only the sound ones.
So you take them all out first, look at them
one by one, throw away the ones that are dubious,
and put back only the absolutely sound ones.
So he started by emptying his mind of all
beliefs.
Laying aside anything in which he could see
the slightest doubt.
And the way he did that was really in three
stages.
He started by laying aside things in which
just on ordinary common-sensical grounds you
might possibly find doubt.
For instance, he reminded himself of such
well-known facts as sticks can look bent in
water, or things can look curious colors to
you if you have defects of eyesight.
These certainly are obvious things.
But he wanted to go beyond those absolutely,
so everyday, kinds of doubt.
The next step he took was to entertain the
idea that perhaps we could doubt we were really
awake and seeing things around us, as we ordinarily
suppose.
For instance, he just entertained the following
thought, he had often dreamt in the past that
he was perceiving things.
While he was dreaming-- at the time he was
dreaming, he thought, just as he does now,
that he was seeing people, or tables, or whatever
around him.
But of course he woke up and found that that
was all an illusion.
How could he be certain that at this very
instant he wasn't dreaming?
Well, that's a un-nerving kind of skeptical
consideration, isn't it?
It had been used by skeptics before, but he
gave it an orderly unsettled place in his
inquiry.
Now of course the dream doubt, the doubt based
on the dream, does depend upon knowing something.
It depends upon knowing that in the past you've
sometimes woken up and found you were dreaming.
It depends on the idea that you know something
about the world.
For instance that sometimes you sleep, sometimes
you wake, sometimes you dream, and so on.
He then took another step.
He said, I will imagine.
I will go to the most extreme doubt possible.
I will imagine the idea of a maligned spirit.
Sort of evil spirit, malicious demon as it's
sometimes called in literature, whose sole
intent is to deceive me as much as he can.
And then I put myself the following question,
suppose there were such a spirit.
It there anything that he couldn't mislead
me about?
And this is of course a pure thought experiment.
It's an abstract thought experiment.
We must emphasize that Descartes never meant
this philosophical doubt to be a tool for
everyday living.
He makes that point over and over again.
They method of doubt, and in particular the
fantasy, or model of the evil spirit, he's
used only as a form of intellectual critique
in order to winnow out his beliefs and see
whether some are more certain than others.
And of course, the ultimate purpose for his
long-range strategy of winnowing away everything
that he can possibly in any imaginable circumstance
as doubt, is to find rock-hard, indubitable
propositions, which can then function as the
premises for arguments.
Absolutely.
There's two things.
He wants to find-- he certainly wants to find
rock-hard, indubitable propositions.
That's to say, the propositions which in some
sense, which of course requires a bit of inquiry
into what exactly is, cannot be doubted.
Which in some sense cannot be doubted, which
will resist the doubt.
He wants them, in part, as premises of arguments.
He also wants them in some rather more general
role, as to provide the kind of background
which will validate the methods of inquiry
I was referring to before.
And we both can say something about how that
works, yes?
But now, after peeling away all imaginably
doubtable propositions, what are the utterly
indubitable ones that he finally arrived at?
Well the famous thing that he arrived at that,
that some French commentators call the turning
point of the doubt-- that's where the doubt
has got to the end and it does a u-turn, and
he starts coming back again, constructing
knowledge again.
The point at which it stopped was the reflection
that he was himself engaged in thinking.
As he said, the malicious demon can deceive
me as he will.
He can never deceive me in this respect.
Namely, to make me believe that I'm thinking
when I'm not.
Because if I have a false thought, well that's
a thought.
So in order to have a deceived thought, I've
got to have a thought, so it must be true
that I'm thinking.
And from that, Descartes drew another conclusion,
or at least he immediately associated with
that another fundamental truth, namely that
he existed.
And so his fundamental first proposition,
or two propositions really, was I am thinking,
therefore I exist.
Or cogito ergo sum, in the Latin formulation,
or as it's often called, the Cogito.
That's that.
It's worth making the point that he himself
made it clear that by thinking, he didn't
just mean conceptual thought, he meant all
forms of conscious awareness whatsoever.
Experience.
Absolutely right.
Experience, feelings, et cetera.
Cogito, in this Latin formulation, equally
for Descartes' French formulations, means
all sorts of things like perceptions, and
pains, and sorrow, not just--
So it wouldn't be unfair to say that what
he was saying was, I am consciously aware.
Therefore, I know that I must exist.
That's right.
That's it.
He does actually, in the great work called
The Meditations, in which this is most carefully
and elaborately set out, he does actually
show a great deal of finesse in pushing the
boundaries of the Cogito forward, step by
step through various kinds of mental experience.
But some of what he gets to is exactly that.
Now in the process of peeling away everything
that can possibly be doubted, in order to
arrive at these fundamental, indubitable propositions,
he himself has shown that from these fundamental
propositions, nothing follows.
That although I am consciously aware, I may
draw all sorts of false inferences.
For example, the external world or whatever
it might be.
From whatever the deliverances of my own consciousness
are.
So I'm conscious only, I mean I can be sure
only of the fact that I am having whatever
immediate experience it is that I am having.
I can't be absolutely certain of any inference
I may make from that.
Well, it depends on what sort of inference
it is.
What he thought was that the mere fact that
I have the experience, as it were, of being
confronted with this table, for instance,
doesn't guarantee the existence of that table.
I mean that was got rid of, even at the dream
state of the doubt.
And of course it's even more got rid of by
our friend, malicious demon, who is made that
I might just have this experience and nothing
actually be there.
So I can't immediately infer from my experience.
What Descartes tries to do is to construct
now a set of considerations which will enable
him to put the world back.
But it has to be said straight away that the
form in which the world is back is rather
different from that of common sense.
We don't just, as it were, having moved all
the furniture out of the attic and because
of the doubt, stuff it all back again in a
totally un-reconstructed form.
We have a different view of the world when
we re-constitute it than we did in our everyday,
common sense experience.
Incidentally, we'll come to how he does that,
but it's a very important fact about the method
of doubt that that is so.
It's extremely important.
Because sometimes people talk about Descartes'
doubt as if all he did, he had a kind of virtuitous
doubt, and then sort of put the whole world
back again afterwards.
But it's very important that not only does
he put it back for very special reasons, but
that what he puts back has actually been subtly
modified by an intellectual critique of how
we can know things.
But now how he puts it back is--
Yes, I was going to say that the point that
I am concerned to get at now is that he seems,
in arriving at these indubitable propositions,
to have painted himself into a corner.
Because he's given himself indubitable propositions,
which he himself has shown at a previous stage
of the inquiry, can't be used to infer any
certain truths about the existence of anything
outside myself.
Well, all he's seen at the earliest stage
of the proceedings is the most obvious way
of inferring the world from them isn't valid.
He's now going to give you a way which he
claims is.
Now of course, some people think that this
actually is a bit of a countering trick, and
that he actually tries to get himself out
of the corner into which he's painted by the
well-known hero of the [? thriller novel ?]. Likely
he threw of his bonds, but I mean this is
how it works.
Now having, as you rightly say, got to the
point at which he sees only the contents of
his consciousness, which he is acquainted
with, there is nothing else available to him.
It's obvious if he's going to put world back,
he's got to do it entirely out of the contents
of his consciousness.
So he's got to find something in the contents
of his consciousness which leads outside himself.
And he claims that what this is is the idea
of god.
He discovers, among the contents of his consciousness,
the conception of god.
And he argues that this is unique among all
the ideas that he has.
Among all the things that are in his mind.
This alone is such the mere fact that he has
this idea proves that there is really something
corresponding to it.
That is to say that there really is a god.
That's a very difficult one for many modern
[INAUDIBLE], isn't it?
Of course.
In fact, he has two different arguments--
both of which he uses in The Meditations for
doing this.
One is an old, medieval argument called the
ontological argument, which is I think-- perhaps
we needn't spend time on that.
That is a kind of logical puzzle.
I think a metaphysical puzzle, but it's much
less characteristic of Descartes.
The one that's really characteristic of Descartes
is the argument which says, I have this idea
in my mind, but I see an absolutely intuitive
necessary principle.
Which is the lesser cannot give rise to the
greater.
The lesser cannot be at the cause of the greater.
Now my idea of god is the idea of an infinite
thing.
And although it's only an idea in itself,
it's nevertheless the idea of an infinite
thing.
It involves the idea that I can conceive an
infinite being.
But no finite creature, as I know myself to
be, could possibly have given rise to such
an idea, the idea of an infinite being.
It could only have been implanted in me by
God himself, has he memorably puts it at one
point, as the mark of the maker on his work.
God, as it were, signed me by leaving in this
infinite idea of god, himself.
When I reflect that the lesser cannot give
rise to the greater in this way, I realize
that since I have this idea of god, it can
only be because there actually is a god who
has created me.
So he's then put in the position of founding
our knowledge of the external world.
On belief in the self-evidentness of the existence
of god.
That's right.
It's absolutely central.
The next big thing goes that it works like
this.
He then says, the things I know about this
god, I know that he exists, I know that he's
omnipotent, I know that he created me, and
I know that he is benevolent.
These are, of course, all traditional Christian
beliefs.
And because God created me, and is benevolent,
he is concerned as much with my intellectual
welfare as with my moral welfare.
What that means is that if I do my bit, and
that's very important.
And I clarify my ideas as much as I should.
And I don't dissent precipitously to things
I haven't thought out properly-- if I do my
bit in that sense, then God will validate
the things which I am then very strongly disposed
to believe.
Now I find that however much criticism I make
of my ideas, however carefully I think out
what is involved in my beliefs about the physical
world and all that kind of thing, I can suspend
judgment in the doubt.
I wouldn't have got to this point if I couldn't.
While I can suspend judgment in this doubt,
I do have a very strong tendency to believe
that there is a material world there.
And since I have this disposition, I've done
everything in my power to make sure that my
beliefs are not founded on error.
Then God will at the end, as is it were, make
sure that I am not fundamentally and systematically
mistaken.
That is, there is such a world.
So by ending up arguing in effect that the
world of science is given to us by a god whose
existence is self-evident, and whose benevolence
is self-evident, he so to speak not so much
answered the skeptics about science as jumped
over them.
He's bypassed them.
Well, what he says is, it's absolutely essential
to his position that he believes that these
arguments that involve God will be assented
to buy any person of good faith who concentrates
on them enough.
That's absolutely essential.
He cannot accept, it would ruin his whole
position, if you accepted the idea that whether
you believe in god is a matter of cultural
or psychological upbringing, and perfectly
sensible people can disagree about whether
there's a god or not, however hard they think
about it.
It is essential to Descartes that to deny
the existence of God, confronted with these
arguments, is as perverse and as totally in
bad faith as it would be to deny that twice
two is four.
And therefore, the idea is that if you lead
the skeptic properly through it, and the skeptic
is an honest man and is not just mouthing
words or trying to impress, and you put these
proofs before him, he must at the end assent.
Now, people have not done this because they
have not thought hard enough.
They haven't split it into, they haven't done
it in and orderly manner.
A lot of the skeptics are, in fact, fakes
who simply go around making a rhetorical position
and don't really think about it.
But if you're in good faith and think hard
enough about it, then you will come to see
this truth.
And then you cannot consistently deny the
existence of the external world.
That's what he believed.
Now one very important outcome, which this
set of arguments had was that of positing
a world which consists fundamentally of two
different sorts of entity.
There's the external world, which is as it
were, given to me by a god on whom I can rely.
But there's me, who is observing this external
world.
And he made a great point, again in this earlier
stage of the argument, when he's stripping
away all the propositions that he can possibly
doubt.
Of saying that when he's considering himself,
and the nature of his self, he can even imagine
himself existing without a body.
That's right.
Absolutely.
And he can't imagine himself not having the
thinking awareness.
No.
That's that's the part about the, I am thinking,
being indubitable.
So, one consequence of that is that you get
a world posited, which insists on the one
hand of thinking entities, which are location-less
and substance-less.
And a world, a material world, which this
thinking entity is thinking about, or observing.
And it's a world of observer and observed.
Mind and matter.
Spirit and material.
Which has become built into the whole Western
way of looking at things.
That's absolutely right, yes.
Now, Descartes' ultimate aim from the beginning,
has been to establish the project of science,
or of what we would call science.
A project of what we would call science.
And by the arguments that you've outlined,
he's now arrived at a certain view of the
external world.
That's right.
Now, how is this external world to be treated
scientifically?
That's-- you remember I mentioned earlier
that when through the help of god we put the
world back again, we didn't put back quite
the same world that we'd thrown away.
That it's criticized in the process.
And in our reflections, we come to the conclusion
that not only there is an external world,
the external world just as my essence as a
thinking thing is simply thought, the external
world has an essence too.
And that's simply extension.
It simply takes up space, that it's susceptible
to being treated by geometry and the mathematical
sciences.
All its, as it were, colorful aspects.
The fact of its color, that there are certain
tastes and sounds, these are really subjective.
They're on the mental side.
They're subjective things that occur in consciousness,
which are caused by this physical, extended
geometrical world.
He had an example which I think is worth mentioning,
it's a very good one, about a piece of wax.
He said, if you take a piece of wax, it has
a certain size and shape in your hand.
A certain color, smell, texture, feel, temperature,
and so on.
And it seems to us to be the combination of
those properties.
If you put the same piece of wax in front
of the fire, it immediately melts.
And then all those things change.
Different color.
Different smell.
Different temperature.
Different everything.
And yet we want to say it's the same wax.
Now, what about it-- what is there about it
that's the same?
Answer, I suppose that there's a continuous
history of space occupancy.
Yes.
There is, as you know, there is a great--
one of the disputing things in expounding
Descartes is what exactly he thought the wax
argument proved.
And how much he thought it proved, just by
itself.
But he certainly did use that example to illustrate,
if not actually to prove, what he thought
was the fundamental idea.
That if it were space occupancy, just being
a piece of space.
Yes.
And it's really curious.
He did actually not think-- he really did
think a piece of space.
He didn't think it was just a thing in space.
Because he didn't believe in a vacuum.
He really did think that the whole world was
one extended item.
And that separate items-- things in it, as
we say, tables or whatever-- really are local
pieces of this in certain states of motion.
Now this, as a foundation for the mathematical
physics of the 17th century, in its own terms,
didn't come off.
I mean, eventually it was going to be replaced
by classical physics and dynamics and Newton
would have a different conception of a mathematical
world.
But he did a tremendous amount to establish
the notion of a physical world which is fundamentally
of a mathematical character.
And permits mathematical physics to be done.
Because it was one of the most important and
striking facts about the Scientific Revolution
starting in the period we're discussing, in
Descartes' lifetime and through his work,
is that the first of the great sciences, as
it were, to get going was in fact mathematical
physics.
Chemistry-- the things that deal with sorts
and things, in much more of that kind of detail,
is of course much more a product of the 18th
19th century, not of the 17th century.
Wouldn't it be fair to say that they Descartes,
in his time, did more to launch the possibility
of science, and to as it were, sell science
to the educated public than anyone else?
Yes.
I should have thought that was probably true.
I mean the figure who was also enormously
famous, and as a matter of fact whose actual
physics is nearer to classical physics as
it came out in the end, is actually Galileo,
rather than Descartes.
But of course, Galileo was more notorious,
perhaps than respectable, because he was tried
and condemned by the Inquisition.
Yes, I mean Descartes' intellectual influence
in this respect, was simply enormous.
Even though the details of his physics were
eventually to be in good part repudiated.
Now up to this point in the argument, what
Descartes has shown-- Descartes hasn't, as
it were, provided us with any physics.
What he's shown is that a mathematically-based
physics is possible.
It's possible, yes.
And is applicable to the real world.
Yes.
Can you expand on that distinction a little?
Yes, absolutely.
What he hopes to have shown, by the maneuvers
we've been through, we've followed so far,
is that, as it were, the world is so constructed
that man is capable of knowing about it.
I mean in that sense, man and the world are
made for each other by God.
There is still a teleological thing at the
end in God.
Even though, of course, man in his essence
is not actually part of nature.
Because man is this immaterial, intellectual
substance, which isn't part of the natural
thing.
Man is not part of nature in that sense, but
he is as it were, his intellection it is quite
well adjusted to it.
And that means we can conduct a mathematical
physics above all.
Now Descartes thought that some of the fundamental
principles of physics could themselves be
known by what we would call philosophical
reflection.
He thought, in particular, we could know by
such reflection that every physics had to
have a conservation law.
There had to be something that was concerned.
We talk about the conservation of energy,
the conservation of force, and so on.
The indestructibility of matter, as it used
to be--
Yes, that's right as it used to be thought.
Of course, now we know the equivalence of
matter and energy through atomic reactions
and so on.
Now, Descarte actually picked on [? the quantity
that was conserved ?], something which wasn't
what was conserved, and indeed in terms of
classical physics, later not even well-defined.
But the idea was there, and that was a prior
right, was to be known by reflection.
Further details of the laws of physics, he
thought required investigation.
And in particular, how the world was actually
laid out.
How different patterns of motion were to be
founded he thought was a matter for experimental
inquiry.
Now this is quite important, because Descartes
is rightly said to be a rationalist philosopher.
That is, that he thinks that fundamental properties
of the world and of the mind and so on, can
be discovered by reflection.
By a kind of philosophical reflection.
And he does not think that everything has
just derived from experience, or experimental
things.
It's sometimes supposed that he was such a
strong rationalist that he thought that the
whole of science was to be deduced by purely
kind of mathematical, or logical reasoning,
from metaphysics.
That if I sat and thought hard enough about
the Cogito and God and matter and all that,
I'd arrive at the whole of science.
He thought no such thing.
In fact, he's absolutely consistent, always,
in saying that experiments are unnecessary
to distinguish it in some ways of explaining
nature and others.
You can build different models.
This is very modern, a very modern aspect
of his thought.
You can build, or construct different intellectual
models of the world.
Within his laws, experiment is needed to discover
which are truly there.
And is experiment seen by him as designed
to test the answers?
Or to give us the material for the premises
to our argument?
It's designed for a number of different things,
actually.
But really the following.
That if you take the fundamental laws of nature,
the principles on which matter moves, there
are a lot of different mechanisms you could
imagine which would produce superficially
the same effect.
You then make differential experiments.
You then arrange a set-up in which one thing
will happen if one model is what's really
there, and it won't if another is.
And so you select between models.
And that really is a quite a good description
of quite a lot of what physicists do.
It's the modern notion of the crucial, or
decisive experiment.
Yes.
And he was very keen on that.
One of the things that Descartes was admiral
about was that it was simply no good blundering
around the world, trying out experience to
see what you could find out.
You had to ask the right question.
And that's again this thing you were saying,
that God is on your side.
If you do your bit, God will not allow you
to be systematically deceived if you don't
systematically deceive yourself.
So what you've got to do is to think of the
right questions to ask.
And then God will assist nature in giving
you the answer.
I think it's worth making the point at this
stage in the discussion that although God
is an absolutely indispensable element to
Descartes in the course of arriving at his
method, once you've got the method, you don't
have to be any sort of believer in God to
use it.
That is an exceedingly important point.
That Descartes wanted to free the process
of science from theological constraints, or
foundations.
Or as one might say, free it from theological
foundations, and hence, from theological interference.
But, of course he was extremely keen to say,
this does not mean that we've produced a godless
world.
We've produced a world which is in fact made
by God, and where our knowledge of it is guaranteed
by God.
The way you have to appeal to God in your
intellectual life, is not in, as you rightly
say, in conducting science, but in proving
to skeptics that it can be conducted.
And Descarte very sensibly thought you shouldn't
spend a lot of time in proving to skeptics
that can be conducted.
You only need to do it once.
He thought he'd done it.
Now let's all get on with it, was his view.
Now one phrase that's commonly used for an
aspect of this whole system that he provided
us with is Cartesian dualism.
We've talked about this already.
You mean the mind body dualism?
Yes, the division of total reality into spirit
and matter.
Now didn't this give him a theoretical problem
of a very important kind?
How do you explain the interaction?
To put it very [? cruelly, ?] how is a spirit
able to push objects in the world around?
Well, I'm afraid, frankly, that the answer
is that he never really did.
Leibniz somewhat scornfully said on this subject--
the interaction-- said Monsieur Descartes
seemed to have given up the game, so far as
we can see.
He did have a theory in a late work, just
before he went to Sweden, he wrote a book
in which he did curiously try to localize
the interaction between mind and body in the
pineal gland, which is a body at the base
of the brain.
But of course, it barely even make sense.
I mean the idea that this purely, sort of
abstract non-material item, something which
is almost, though not quite as it were, the
counting of a number, could induce a change
in the physical world by redirecting certain
animal spirits, which is what he believed.
It's so difficult to see conceive, even in
sort of abstract principles, that it was a
kind of scandal for everybody.
I mean a lot of the philosophy of the 17th
century, and indeed subsequently actually,
addressed itself to trying to find some more
adequate representation of the relation of
mind and body than Descartes actually left
us with.
Nonetheless, some form of Cartesian dualism--
of distinction between an observer and observed,
subject and object, got into Western thought,
for something like 400 years.
I think the distinction between subject and
object, known or unknown, is the distinction
which is simply impossible for us to do without.
There are indeed philosophical systems that
constantly try to say that we simply have
no conception of the known independently of
the knower.
We make up the whole world.
But of course, the trouble about that is that
it's very difficult-- well, complete idealism,
the idea that everything there is really a
product of our minds, to put it a little simply,
is quite difficult to believe.
We all do, and certainly all science does,
depend very much on a dualism between the
knower and the known.
A world which we can know independently of
our process of knowing it.
What I think very few people now assent to
is the absolute dualism between the completely
pure mind and the body.
The knower has to be seen as indeed, of course
it was in philosophy earlier than Descartes,
for instance by St. Thomas or by Aristotle,
the knower has to be seen as an essentially
embodied creature, him or herself, as it were.
And not just as a kind of pure soul.
What would you say its main influence on Western
philosophy has been?
Descartes' influence has been simply immense,
and still is.
Well if you summarize it in one thing is that
is that Descartes, and almost Descartes alone,
who brought it about that the center of Western
philosophy for all these centuries has been
the theory of knowledge.
The idea that philosophy starts from the question,
what can I know?
Not from the question, just what is there?
Or how is the world?
But what can I know?
And not just what can I know?
But what can I know?
That is, that it starts from a first-personal,
egocentric question.
And it is very important for the structure
of Descartes' system-- I mentioned right at
the beginning that it was possible in his
time to think that perhaps science could even
essentially be done by one person.
But even if you lay that historical context
aside, it is a very important part of his
enterprise that it is-- it is autobiographical.
It's no accident that his two great works,
The Discourse on the Method, and above all,
The Meditations, are written in the first
person.
They are works of self-- philosophical self-inquiry,
and this first-personal and epistemological
aspect, that is the aspect concerned with
the theory of knowledge-- has been the overwhelming
influence of Descartes.
Now, given that all that are wrong with the
philosophy that we've touched on, and of course
there are more than we have touched on.
And given that the central concern of philosophy
has now moved away from the problem of knowledge,
which was made central by Descartes, why is
the study of Descartes now as valuable to
us as it is?
If I may put this question in a personal way,
you, Bernard Williams, you've spent, as far
as I know, almost 20 years of your life working
on a book on Descartes.
You must've thought this enormous investment
of yourself and your life was worth it.
Why?
I think for two reasons.
And let's lay aside the purely case of historical
understanding the role that Descartes has
played in getting us into our present situation.
Where I think that just to know what he said
in a little bit of detail is very important,
simply to understand who we are and where
we've come from.
But the reason why I think that this book,
when I say this book, above all I mean the
particular book called The Meditations, is
a book that one very much, if one is interested
in philosophy wants to read now, is because
the path it follows, the path of asking, what
do I know?
What can I doubt?
And so on.
Is presented in an almost irresistible way.
And the point is, it's not an accident that
this emphasis in philosophy has been so overwhelmingly
important.
But just because Descartes, just because he's
a dazzling stylist, or something of that kind,
could kind of perform a long-distance mesmerism
on the mind of Europe.
That isn't the reason.
The reason is because he discovered something
which is intrinsically compelling.
That is, the idea that I ask myself, well
I have all these beliefs, but how can I get
around behind my beliefs to see if they're
really true?
How can I stand back from my belief to see
which of them are prejudices?
How much room for those in skepticism?
These are really compelling questions.
And it needs an enormous amount of philosophical
imagination and work to get oneself out of
this very natural pattern of reflection.
And another very related question, which comes
before you very dramatically in this extraordinarily
written book, is not just what can I know?
Because as we discovered already in the Cogito,
what am I?
We can imagine ourselves.
We have this power of the imaginative extraction
from our actual circumstances.
We can imagine ourselves looking out on the
world from a different body.
We can imagine looking into a mirror and seeing
a different face.
And what's important, looking into a mirror,
seeing a different face, and not being surprised.
And this gives us the idea, a very, very powerful
idea, that I am independent of the body and
the past that I have.
And that is an absolutely foundational experience
of the Cartesian idea, that I am somehow independent
of all these material things.
Cartesian dualism, though once you look at
it as it were sideways as a theory, it's immensely
difficult to believe for the reasons that
we've touched on.
It also has [UNINTELLIGIBLE] that it's almost
impossible to resist, if you go at it through
a certain set of reflections.
But I think the set of reflections that Descartes,
with unexampled clarity and force, lay before
you to lead you down that path, as I think,
mistaken path, are so not only powerful themselves,
but as it were, near to them both.
That it is a prime philosophical task to try
and arrive at an understanding of oneself,
one's imagination, one's conception of what
one might be, that one would free one of that
dualistic model.
Thank you very much.
[MUSIC PLAYING]
