Prof: Okay,
so today what we're going to
talk about is the logic of
science.
And there's a reason that this
lecture comes at this point in
the course.
 
Most of you are now just
getting to the point where
you're going to get serious
about writing your papers--
that's going to happen during
the next couple of weeks--
and in doing that,
you're going to be making
judgments about how good is the
science that you're reading in
the papers.
 
So I want to raise,
in your minds,
this issue of what constitutes
science and what is not science,
and what's good science and
what's bad science,
so that you'll yourself start
to develop your own criteria.
And these are issues that have
occupied a lot of bright people
for a number of centuries;
so I'll only be touching on a
few points this morning,
but they're important ones.
Now science is basically
culture's answer to the big
problem of epistemology,
which is how can we know
anything at all?
 
How do we know that there is a
material reality?
And this issue,
as you know,
goes back to Plato and
Aristotle,
in the Western tradition,
and in each of the other major
cultural traditions these issues
have been debated.
There's a lovely humorous story
in Zuang Zi from the third
century B.C.
 
in China, about this issue.
 
So basically if you look at
what all the different parts of
our culture do for our society,
this is the role of science.
It tries to give some kind of
objective message about the
nature of reality,
to everybody in the culture,
if they want to pay attention.
 
Now in talking about this,
I am essentially assuming that
you've got some background in
these issues;
and not all of you do,
but there are places where you
can catch up.
 
For example,
Bertrand Russell wrote a
somewhat opinionated but amusing
and informative history of
Western philosophy,
where you can sit down and in
the course of about a month read
through all of the major issues
that have been debated.
 
I'm going to assume that you
know that David Hume
demonstrated that inference
doesn't lead infallibly to
truth.
 
And that's an interesting point
and it's one that I think a lot
of modern philosophers probably
would disagree with,
to some extent.
 
Basically what Hume was arguing
about was how do we know that in
fact the sun will rise in the
east tomorrow morning?
And the fact that it's just
done so, for a long time,
is no guarantee that it will do
it again.
We need to know something else
in order to feel confident that
the sun will rise in the east
tomorrow morning.
And, in fact,
what we've got going for us now
is we've got a model of the
universe in which the earth
spins on its axis and planets go
around the sun and stuff like
that.
 
That is a theory.
 
It's a model of the universe,
and it's been so extensively
validated and connected to so
many observations that it would
be mad to deny its reality.
 
But that's quite different from
just sitting there,
without having that model of
the universe in your head and
noting that the sun comes up
every morning,
and just accumulating instances.
 
And what Hume essentially
pointed out was that just the
accumulation of instances is not
leading you infallibly to the
truth;
that there could be alternative
explanations.
 
So without that contest of
alternative explanations having
taken place, we don't really
know that the sun will come up
in the morning.
 
By the way, it is rather
similar with the issue of
something like is DNA the
genetic code,
which is a little bit closer to
the subject of this course.
It was not at all clear,
say in 1945,
in the Avery experiment,
that DNA was the genetic
substance.
 
And as late as the discovery of
the structure of DNA in 1953,
by Watson and Crick,
there were still people who
felt that DNA probably wasn't
the genetic code;
that it was probably some
protein that contained the
genetic code.
 
And so there was a contest of
alternatives,
there were critical experiments
that were done,
and then the evidence
accumulated to the point where
it would become mad to deny that
DNA is the genetic molecule,
and that it has a particular
triplet code and so forth.
So that's a way of showing how
a working hypothesis survives a
contest of alternatives to
become something that then gets
operationally accepted as truth.
 
>
 
And I suppose that it is
conceivable that someone might
now come up with an observation
that would convince us that,
at least in some cases,
DNA wasn't the genetic code.
But for all intents and
purposes, this contest of
alternative ideas,
through experimental
demonstrations,
leads to something that science
then accepts pretty much as
truth.
And what I'm telling you is
that these theories about the
structure of reality are
basically arrived at by a
contest of ideas that is being
testing empirically over and
over again,
and you're accepting the last
one that's left standing.
 
So here's more or less what
scientists think.
They think there's a material
reality and they think we can
discover its nature.
 
Not everybody on the planet
agrees with that.
We can eventually agree on what
we've discovered.
At the leading edge of science
there's plenty of disagreement
about the nature of reality;
that's the whole point about
the contest of alternative
hypotheses.
So what we call science is
limited to knowledge about the
part of material nature that is
currently accessible by our
current technology,
our current techniques,
our current investment,
and on which we can agree;
and that agreement can take
some time.
And not everything in material
nature is accessible.
If you just go back and you
look, for example,
prior to the discovery of- or
to the invention of sensors that
could detect the orientation of
magnetic fields on the floor of
the ocean,
we didn't have access to the
evidence that demonstrated plate
tectonics.
Okay?
 
So that's something that
happened after about the Second
World War, and that evidence was
accumulated actually mostly in
the '50s and '60s.
 
Prior to high throughput DNA
sequencing techniques,
we did not have access to the
deep structure of the Tree of
Life.
 
So those are technological
advances that then open up
things that we can get answers
to.
Currently we do not have the
technology to decide about
whether or not string theory is
the best way to look at the
very,
very fine structure of
substances, and therefore
whether or not time travel is
possible,
or there are worm holes in
space time,
and stuff like that;
we don't have enough technology
to get us to where those ideas
are going.
 
So this is something that
depends on the current state of
technology.
 
Now the part of knowledge that
people can agree upon,
through this debate of
alternatives,
is what we call science;
and that means that somebody
else can replicate your claim.
 
They can't replicate your claim
unless you've described it
clearly.
 
That means if you're reading a
paper, for one of your papers,
and somebody can't tell you
clearly what they've done,
they're not doing a good job.
 
They have to be able to write
clearly in order to complete
this part of the logic.
 
One of the loveliest cases of
this that I ran into was now
almost 30 years ago.
 
I was invited to Scandinavia,
and there were people there in
departments in Göteborg --
Gothenburg -- and in Lund and
in Oslo and in Stockholm,
and Uppsala,
who did not have any professors
who could teach them modern
behavioral ecology.
 
But they were fascinated by it,
and the professors that they
had,
who were experts in things like
comparative morphology,
were willing to let their
students study this new subject,
and the students taught it to
themselves entirely from the
scientific literature.
It had been so effectively
described in journals that they
could pick up and read that
they'd bootstrapped themselves
into becoming world experts in
behavioral ecology,
and the Scandinavian School of
Behavioral Ecology has become a
dominant force in the field.
 
They did it without having any
professors to teach them,
because people could write good
papers.
So that is one of the reasons
that I'm so enthusiastic about
people learning to write
effectively,
because it can actually
accomplish cultural
transformation.
 
I think I've already made this
point well enough.
Okay.
 
So how do we agree?
 
Well here are some issues.
 
I'm going to be talking a bit
about the method of multiple
working hypotheses,
about falsifiability,
about strong inference,
about scientific revolutions,
and about the issue of whether
philosophers understand this
better than scientists do.
 
And I'd like to touch a little
bit on where ideas come from;
and I've already given you a
couple of hints on that in terms
of support for writing your
papers.
By the way, if I just go
through this,
this is certainly not a
rigorous and inclusive coverage
of all of the important points
in the philosophy of science.
It is just hitting a few high
points that I hope will
stimulate you to think about
these things,
and perhaps you'll want to read
further.
So there are many different
ways of doing this,
but in choosing these
particular things I am hitting
on issues that have particularly
occupied the minds of
biologists.
 
So it's not random,
in that sense.
Okay, so let's go back to
T.C. Chamberlain.
T.C. Chamberlain was the head
of the Geological Society of
America,
and he gave a wonderful
address, which has been
reprinted several times,
and which is part of your
reading for Section this week.
And basically what Chamberlain
says is that we fall in love
with our own ideas,
and therefore we're biased,
and so when we look at a
pattern of data,
we will have a tendency to pick
out the parts of it that support
our preconceptions and to leave
out the parts that don't support
our preconceptions,
and if you're interested in an
objective view of reality,
this is a bad thing to do.
So how do we protect ourselves
from this?
Well the best way,
he thought, was to explicitly
come up with a set of multiple
working hypotheses,
that are actually different
from each other,
and then weigh the evidence for
and against each of them.
So this is a way of protecting
ourselves against our love for
our own ideas.
 
Now sometimes,
several can all be correct,
and that is the case whenever
hypotheses are not mutually
exclusive,
where they could all actually
be working at the same time.
 
Sometimes that is true and
sometimes that's not true.
That tends not to be true when
you're talking about particular
molecular structures.
 
There is normally just one
molecular structure.
If your techniques are not
good, there are some
alternatives,
but when you get them really
good, usually there's just one.
 
But often there are several
different selection pressures
that will result in the same
outcome.
And you've seen that with
sexual selection.
Okay?
 
So a female could be choosing a
male for good genes,
or because he's got lots of
resources,
or because he'll have sexy
sons, and in fact those could
all be true at the same time.
 
Now one way to get to
objectivity--
given that, in fact,
the observer,
the human,
always has kind of a selfish
bias towards their own idea--
one way to achieve objectivity
is to try to demonstrate
systematically that a hypothesis
is wrong.
 
And if you try to refute it,
rather than to confirm it,
and you can't refute it,
it just is stubborn,
it will not go away,
then maybe it's right.
>
 
Okay?
 
So this is the idea behind
Popper's falsifiability
criterion.
 
Karl Popper,
a very influential philosopher
of science, member of the Vienna
School;
that was the school of people
that also had Wittgenstein and
Carnap and a number of others in
it,
and these were people who were
engaged in very strong debate
about how to make sense of the
discovery of reality in the
post-quantum mechanics world.
 
And there had been a great deal
of uncertainty in the basis of
our knowledge,
that entered in,
in the early twentieth century,
with the discovery of quantum
mechanics and of the theory of
relativity.
To put you back into that,
for two or three-hundred years,
people had thought that Newton
had actually figured it all out,
and then from about 1880 up to
about 1910 the Michelson-Morley
experiment and things like that
had demonstrated that speed of
light was a constant in the
universe,
and the only way that that
could really be understood was
through Einstein's special
Theory of Relativity.
And that and the subsequent
discovery of quantum mechanics,
which came out of the
photoelectric effect and other
things,
made people realize that it was
possible for science to go
cruising along for a couple of
centuries,
thinking that it was right,
and then to discover that it
was wrong.
And that suggested,
well that could happen again,
and it could happen in places
where we don't expect it.
So what are we going to make of
all this?
Well one of the responses is
Popper's falsifiability
criterion.
 
So what Popper says is that we
can never actually prove that an
empirical statement is true,
for there are always
alternatives that are possible.
 
So these alternatives we might
not know about,
but that would be a failure of
our imagination,
it would not be a failure of
logic.
However, we can demonstrate
that things are false.
So Popper claims this is what
distinguishes science from math.
Okay?
 
You can prove a theorem in math;
you cannot prove an observation
in science.
 
So proof means true at all
times, in all places.
I think that you're currently
scratching your heads and
wondering,
well in what sense is it not
true that gravity is present
throughout the universe,
or that DNA is the genetic
code, or any of these other big
things that we know in science.
 
Well I would say that the thing
that distinguishes science from
math,
in statements like that,
is that math is 100% certain,
and science is trying to get to
the limit of that 100%
certainty;
so some of it's up there at
99.99, I would say,
or even closer.
 
But with math it's simply
logically true,
and with science it's a matter
of empirical demonstration.
So because of that,
Popper suggested that the
difference between science and
non-science is falsifiability.
If in principle you can
demonstrate that something is
false,
if a certain observation that
one could imagine could
demonstrate it,
then you're dealing with
science, and if you cannot
imagine ever making an
observation that would
demonstrate that something is
false,
then you're dealing with
non-science.
Okay?
 
So that's how Popper
distinguished science from
religion.
 
Now I think that there's
something to this.
Basically what I take away from
this personally--
excuse me, I want this last
statement down here--
is that we trust ideas that
have taken the strongest hits we
can throw at them and they're
still standing.
Okay?
 
So that's, to me,
the best criterion for trying
to see whether people are doing
natural science.
They're not trying to confirm
the ideas, they're trying to be
critical;
they're throwing everything
they can at them,
and by George you can't knock
them down.
 
Now one person who more or less
implemented this was a chemist
named Platt, and you're going to
read his paper for Section this
week as well.
 
So Platt was one of the
physicists who had come into
biology,
a physical chemist who had come
into biology,
and he asked himself,
"Why is it that some
fields make progress faster than
others?"
 
And he said,
"Oh, it's-- actually we
know.
 
They have a good method.
 
It's called strong
inference."
So devise alternative
hypotheses--that's Chamberlain.
Devise crucial experiments to
exclude hypotheses--that's
Popper.
 
Do the experiments so well that
nobody can argue with you,
and then recycle the procedure.
 
So he said people who are
making progress do that,
and people who aren't making
progress don't do that.
And so in comments on this,
that had been quoted in the
letters,
Leo Szilard,
who is one of the founders of
molecular genetics,
molecular biology,
said the problems of how you
induce enzymes,
or how you synthesize proteins,
or how you form antibodies,
are actually something you can
do with experiments,
that you can finish fairly
quickly,
and it will only take a few
experiments to do it.
 
So actually if intelligent
people were just dealing with
this issue, we would get there
pretty quickly.
And a young ambitious scientist
says,
"It's essentially the old
question: how small and elegant
an experiment can you
perform?"
And a descriptive scientist,
an electromicroscopist,
who is a not a person who is
normally engaged in these
testing of alternatives says,
"Gentlemen,
this is off the track.
 
This is philosophy of science,
this isn't what we really
do."
 
And Szilard says,
"I'm not quarreling with
third-rate scientists.
 
Okay?
 
I'm quarreling with first-rate
scientists."
And then this guy writes in,
a little bit afterwards,
and says, "So,
should I commit suicide?"
So you see people get kind of
stirred up about this stuff;
and there are some remarkably
arrogant people out there.
>
 
So where does this work and
where does it not work?
And by the way,
one of the best demonstrations
of this method that I've ever
seen was when Tom Pollard gave
his lecture in that half-credit
course for freshmen,
and Tom came in and described
how he had figured out how cells
move,
how actin fibers are used in
the motion of cells,
and it was just a tour de force
of strong inference,
it worked like a charm.
Okay?
 
And it was all about cell
structure.
So where does it work best?
 
Well what's the single
mechanism;
what's the structure?
 
That is where strong inference
really works well.
It doesn't really work so well
where there are several
different correct answers,
where you've got multiple
causation going on.
 
That's often much more often
the case in ecology and
evolution than it is in
molecular and cell biology,
and it's certainly much more
often the case in the social
sciences than it is in the
natural sciences.
But it's a good philosophy.
 
Okay?
 
It's a good starting point.
 
It's good to realize that
that's a good standard to set,
and to see how far you can push
the process towards it.
So, for example,
the genes in an environment
interact to cause phenotypes.
 
So it's not just genes,
it's not just environment that
are causing heart disease.
 
And you can use experiments and
hypotheses to get at these
interactions;
and that's clearly an important
point that we would like to know
about.
But when you look at all the
causes of heart disease,
there are at least five or six,
and they're interacting with
each other,
and when a person dies of a
heart attack,
it is often difficult to say it
was only for this reason that
they died of a heart attack.
Now strong inference actually
won't work at all in a field
like astronomy,
geology, paleontology or
systematics.
 
And that's because we can't do
experiments.
Nevertheless,
we can do observations that are
so precise that they become
convincing.
So there is a rigor in
descriptive science that is not
captured by this paradigm of
strong inference.
Okay?
 
For example,
probably the most extreme
example I know of is this.
 
Quantum chromodynamics makes a
prediction for the fine
structure constant,
to so many decimal places that
it predicts it to within half of
the diameter of a piece of
tissue paper,
compared with the distance
between Washington DC and San
Francisco.
Now if a theory is able to make
a prediction quantitatively,
which is that precise,
you're not going to ask some
kind of high-faluting
experimental verification of it.
You're just going to measure
the fine structure constant and
if it measures down to that many
decimal places,
you're going to scratch your
head and say,
"Well, you know,
I think maybe the theory has
got something to it.
 
It's capturing something
important about the nature of
reality."
 
Things like continental drift
and the Big Bang are accepted
without experimental
confirmation.
By the way, thank God we're not
doing experiments on the Big
Bang.
 
That would be a little bit
exciting >
if we were doing that one.
 
But you might want to think
that if strong inference is the
paradigm of good science,
then why is it that we are now
so happy with the notion that
continental drift is going on
and that the Big Bang occurred?
 
And I think that what you'll
find is that there is a theory
about how it works,
and the theory makes a long
series of predictions,
and many, many of these
predictions have now been
confirmed by observation;
not by experiment but just by
observation.
And if you line up other
alternative theories,
for say the location of the
continents on the planet,
or say the residual cosmic
radiation,
or something like that for the
Big Bang,
you'll find that the
alternatives don't do so well.
Okay, now there is another
possibility for what goes on in
science, and that is this
romantic paradigm of
revolutionary science.
 
And if you would like to read a
piece of glorious philosophical
rhetoric,
read Thomas Kuhn's 1962 book,
The Structure of Scientific
Revolutions.
Kuhn was a guy who had been a
physicist and then he went into
the history of science.
 
He was a Junior Fellow at
Harvard.
He decided to make the
Copernican to Galilean- the
Copernican revolution;
so overthrowing the Ptolemaic
structure of the universe and
moving to a model of the
universe in which the sun was at
the center and the earth went
around the sun,
and then eventually to the
Galilean and subsequent model of
the universe in which the earth
is a small planet circling an
obscure star,
on the fringe of a thoroughly
normal galaxy,
which is one of billions of
galaxies.
So that kind of change in world
view he described as a
scientific revolution.
 
And he described it as a
paradigm shift,
a shift in the whole way that
we look at the world.
And there have been some others.
 
Okay?
 
So Newton to Einstein,
plate tectonics.
And the idea here is that the
paradigm shift is so profound
that people are not able to
communicate across the divide,
so that once you have seen,
for example,
that the continents are in
motion, you can actually no
longer have an intelligent
conversation with your
geological colleague who doesn't
realize that yet,
because it's such a deep change
in the way that you look at the
world.
 
That one actually--I watched
some of these people communicate
across that divide;
so that wasn't really that kind
of paradigm shift.
 
If that really is true,
then the old generation has to
die out before the insights of
the new generation can be
accepted.
 
And if you are a young
revolutionary,
and you're getting a lot of
resistance from the older
generation,
this might be some kind of
solace, that actually you're
younger than they are and you're
just going to outlive them.
 
Okay?
 
Well I think that this is an
interesting set of issues,
because somebody like Charles
Darwin really was a
revolutionary.
 
There's been nobody who has
more profoundly changed the way
that we think about the human
condition and what a human being
is and so forth than Darwin.
 
But Darwin didn't want to be a
revolutionary.
He wanted to be a normal member
of the British upper
middle-class,
who wasn't upsetting anybody.
>
 
And he was conservative.
 
He wanted to be acceptable to
the establishment,
and so he went through rather
elaborate maneuvers,
to try to make himself
digestible.
Steve Gould was not really a
revolutionary but he wanted to
appear to be one.
 
If you go back and you look at
what Steve's written about his
encounter with Kuhn,
in 1965, when he was a graduate
student at Columbia,
you can see that he was seduced
by this idea that revolutionary
science is great science,
and that's what he wanted to
become.
So he had important ideas;
there's no question that Steve
Gould had important ideas,
but he wanted to sell them as a
paradigm shift that would change
profoundly the way that
everybody looked at the world,
and he actually overshot his
mark and he created exaggerated
expectations.
So there was a bit of a
backlash against him because he
was making claims that couldn't
really be supported.
And that is,
I think, kind of unfortunate
because he had some important
ideas;
just oversold them.
 
So is it worth worrying about
being a revolutionary scientist?
Well I think we all have to be
a bit modest about whether we
can tell whether we're currently
making a contribution that's
going to make any difference at
all.
And the only thing that decides
is history, and history chews
this stuff over long after we
are dead.
So it's really only history
that can identify a major
scientific advance.
 
It's very difficult,
right in the middle of the
generation that's experiencing
it,
even though it might have
gotten a Nobel Prize,
to be sure that it's really
that fundamental,
because it just takes
perspective and time.
So if you're on the scene and
you're enmeshed in the process,
your own estimate of the
contribution is kind of
unreliable;
and, to go back to Chamberlain,
we're all in love with our own
ideas,
and so we all have a tendency
to think that what we're doing
is the greatest thing ever.
 
And that's simply just not
necessarily true,
and it's kind of hard to tell
until history takes its course.
So the best way to cause a
change is to take the current
state of affairs and push it as
far as it will go.
So taking the current state of
science,
what Kuhn might call boring,
normal science,
and pushing its limits and
discovering where they break
down is probably the most
effective way,
in the long-term,
to really cause major
scientific advance.
 
So, for example,
the Michelson-Morley
experiments,
where they were simply
measuring the speed of light in
the direction of the earth's
movement around the sun and in
the other direction,
and they discovered that it was
the same in both directions,
even though they knew that the
earth was moving around the sun
at hundreds of thousands of
miles per hour,
is a very good example of this.
 
That caused a crisis.
 
And there haven't been very
many experiments in the history
of biology that have had that
kind of impact,
but there have been a few.
 
The Avery experiments in 1945
identifying DNA as the genetic
substance in bacteria are a good
example of that.
There have been some others.
 
So if you make a premature
attempt at revolution and you
overshoot the mark,
then the attempt tends to
collapse under its own weight.
 
There's a whole cottage
industry of criticisms of Kuhn.
You can find conferences that
have gone out and found maybe
seventy or eighty different
senses in which Kuhn used the
word paradigm in that
paper.
So I would say that whether
it's worth worrying about
revolutionary science at all,
or whether it's worth trying to
be a revolutionary scientist,
is an issue which is open to
pretty serious discussion.
 
Now what about post-modernism?
 
Post-modernism is variously
defined, and some of it I think
is quite interesting and worth
reading.
When people say Post-Modern,
they usually think of the
French School of Literary
Criticism and Philosophy;
they think of Jacques Derrida,
they think of Lacan,
they think of Foucault.
 
And there are insights that
those guys have had,
some of which I think should be
part of the intellectual
equipment of any well-educated
person.
And particularly among that
crew I particularly admire
Foucault because Foucault,
for example,
discusses things like is the
definition of madness a function
of the current power structure
of society?
I think that's an interesting
question and I think that
there's some historical evidence
that it is, to a certain degree.
So I think there are important
issues there,
and most of that I think has to
do much more with literary
criticism in the social sciences
than it does with the natural
sciences.
 
But the people who got into
this decided that they might
want to turn this armament of
literary ideas onto natural
science.
 
And they picked up on Kuhn,
because if you could show that
science consists of a series of
revolutionary paradigm shifts,
that would mean that science is
more socially constructed than
empirically verified.
 
Okay?
 
So it's like one paradigm is
one period of mass hysteria,
and then the next paradigm is
another period of mass hysteria;
and there isn't anything going
on here,
other than that people are
tending to agree with each other
on the nature of reality,
but then they're changing their
minds.
 
Okay?
 
Well most of science actually
doesn't proceed according to
Kuhn's model of revolutionary
science.
It's going by the accretion of
well-tested hypotheses.
They're mostly much smaller
than a paradigm.
It's walking with small steps.
 
So it's not built up the way
that say Kuhn's Copernican
Revolution would make it look
like.
And science does succeed in
describing nature in ways that
don't change as science
advances.
So you can ask yourself
questions like this.
In what sense was Newton still
right after Einstein?
Well he was right enough to get
people onto the moon.
You didn't need the correct,
the Einsteinian corrections to
get man to the moon.
 
I think that at that scale
you're off by a matter of meters
or seconds, rather than by
kilometers;
things like that.
 
In what way is Darwin still
right after the rediscovery of
Mendel's laws of transmission
genetics?
Well we're all in a big frenzy
of honoring Darwin's 200^(th)
Anniversary this year;
and he was obviously clearly
right on some very important
points, and wrong on some
others, and science manages to
distinguish that stuff.
So the point is that when the
natural science community gets
down to the task,
and it focuses long and hard on
an important point,
it can actually tell you pretty
well what the nature of reality
is;
and it's not that we're dealing
with successions of mass
hysteria on something like that.
 
Now that said,
one of--there are moderate
post-modernists who will say,
"Yes, but the social and
political context does bias the
kinds of questions that are
tested."
 
And I think there's some truth
to that.
And I think there's some truth
to the idea that if science was
dominated by women,
that they would be testing a
different set of questions than
if it were dominated by men.
And I think that if it were
dominated by Marxists,
that they would be testing
different sets of questions than
if it were dominated by
Capitalists.
But I think that the objective
weighing of alternatives is
going to cause all of those
different traditions to arrive
at the same point eventually.
 
Because Mother Nature doesn't
care whether you're a man or a
woman, or a Marxist or a
Capitalist;
Mother Nature just is,
and she's going to give you
answers.
 
Now science consists of shared
knowledge--that's what we can
agree on--and that doesn't mean
that science is a social
construct.
 
Science is accumulated by
humans having social
interactions,
but that doesn't mean that it's
arbitrary.
 
So it's making progress,
and it's expanding the part of
reality we can agree on,
and eventually reality has been
checked by so many methods that
we converge;
any independent intellectual
tradition would converge on
reality as it actually is.
 
And that doesn't matter whether
you would start this process
coming out of a Buddhist
tradition or a Christian
tradition or whatever;
you would eventually end up
with quantum chromodynamics in
physics, and you would
eventually end up with cell
biology and evolution in
biology.
 
I think that there's a lot of
fun that the philosophers of
science have in arguing about
what scientists actually do and
what's the best way to do it.
 
But I think the thing that the
scientist needs to take away
from it is just agreeing that we
can all be critical about the
hypotheses we pose,
and that the tests that they
have, have to withstand,
and the ones that we can agree
on they have withstood.
 
If we can agree that we're
going to be critical of each
other,
and we will do so in a
civilized way,
and we will insist that we will
only accept constructive
criticism,
and we will agree that we will
only try to give constructive
criticism,
because we want to have this
play of alternatives,
and we know that's the only way
we can get to an accurate
description of reality,
then we can do good science.
 
And I don't think that we have
to get much fancier than that
agreement, in philosophical
terms.
Now if we want to be
philosophers of science,
we can go and get as fancy as
we want;
that's another issue,
that's another field.
But what the working scientist
at least needs to do is to
realize that something like this
is going on.
Okay.
 
I'll now give you Western
philosophy in about two minutes.
Okay, so philosophy starts out
as being essentially what we
would now call education in
general, learning in general.
And then parts of it become
mature, and they have then
significant elements that are no
longer subject to debate.
So they split off.
 
The first thing that goes off
is math, then physics.
So Math gets split off by,
arguably oh second century BC,
I would say.
 
Physics gets split off by
roughly the time of Galileo,
between Galileo and Newton.
 
And of course Astronomy quickly
follows.
And then with Lavoisier and so
forth, the end of the eighteenth
century, Chemistry splits off.
 
Then Geology becomes a special
subject, pretty much in the
nineteenth century,
and so does Biology.
So what is then left in this
field of knowledge that we call
philosophy, that used to be
everything?
Okay?
 
Well it consists largely of a
set of very interesting issues,
about which we remain
uncertain.
So given that,
should scientists,
who largely agree on how to
proceed,
accept dicta that are handed
down by philosophers who often
don't agree on what they're
taking about?
Well I would say that
scientists shouldn't accept
simple recipes from
philosophers,
especially if they haven't done
science themselves,
but they should listen to
reason from those who have the
perspective of standing outside
the endeavor.
So one should not dismiss the
philosophers out of hand.
They're often very bright
people who are making good
points,
but they may not have the
practical experience to
understand exactly what
difference their points make.
 
Now the final thing that I'd
like to mention is a little bit
about creativity.
 
So where do ideas come from?
 
And after all I've been talking
about science as a play of
alternatives,
and we have alternative models,
alternative hypotheses that we
want to generate,
and that if we can get them
playing off of each other,
then we can use that as a tool
to try to perceive reality.
Well the best study of where
these ideas come from,
that I'm aware of,
is called The Psychology of
invention in the Mathematical
Field,
by Jacques Hadamard.
 
And Hadamard was a student of
Henri Poincaré,
a great French mathematician
and physicist,
and Hadamard's own personal
research agenda was number
theory;
he wanted to understand the
distribution of the prime
numbers on the real line.
But he was also fascinated by
where do people get these great
ideas?
 
After all, he had hung around
Poincaré,
he knew him,
and he had more or less grown
up at the time that Einstein was
having his ideas.
And so he went and he talked to
Poincaré
and he talked to Einstein,
and then he wrote down what he
discovered, from his interviews.
 
So it's more or less a history
by interview.
So Poincaré
described a case of stepping
onto the bus in Paris,
and he said, "You know,
I had just submerged myself in
this problem."
It had to do with an issue,
an abstruse mathematical issue,
having to do with quadratic
forms.
So Poincaré
just sinks as deeply as he can
into this,
and he gets totally frustrated,
and he just can't go anywhere
with it and he puts it aside.
And about two months later he
is stepping onto the bus in
Paris when suddenly the idea for
the solution appears to him,
full-formed in his head,
and he says,
"You know,
when I sat down and I started
just making a few notes,
I knew that when I got home I
would be able to write the whole
thing out."
It's almost like Coleridge
writing Kubla Khan.
So if that darn neighboring
minister hadn't come to
Coleridge's door,
we would have another ten pages
of poetry like Kubla Khan,
because Coleridge got
interrupted in the middle.
 
Poincaré
was pretty sure he could get
the whole thing out,
and he did.
He went out and he went home
and he wrote down the paper on
quadratic forms.
 
And similarly Kekulé
had this dream of a snake
biting its tail.
 
And Einstein described similar
things, coming up with special
relativity.
 
And so the sequence basically
is there has to be a period of
hard work,
and you have to push yourself
right to the limit,
trying to figure out the
solution to some puzzle.
 
Then you go to sleep,
and maybe the next morning,
or maybe two months later,
something will occur to you.
Your brain is processing
overnight.
It is making connections.
 
It's trying out all sorts of
things, and all of the clutter
and bustle of every day is
getting in the way.
And believe me,
now that we have iPhones,
and we have Twittering,
there is a lot of clutter and
bustle that gets in the way
during the day;
and some of you are probably
surfing the web while I am
saying this.
 
So this point,
that if you can simply put all
that stuff aside and really
concentrate hard,
and then let your subconscious
do the job,
you will be surprised at what
you come up with.
We are all probably more
creative than we give ourselves
credit for.
 
So these things don't happen to
anybody.
They only happen to those who
have prepared themselves by
working hard.
 
So the overview of this is
basically that creative new
ideas, about how the world
works, can come from anywhere.
So this contest of alterative
hypotheses in science,
those new ideas can come from
anywhere,
but they most often emerge from
the minds of people who have
worked very hard to understand
something.
So that's the raw material.
 
And, by the way,
this raw material usually
emerges in the minds of young
people.
It doesn't so frequently emerge
in the minds of the old guys
with white beards.
 
Okay?
 
It's something that emerges in
the minds of young peoples.
And particularly in math and in
physics, those people are often
between the ages of 20 and 30.
 
It appears that in biology
often they're between the ages
of 30 and 40,
just because it's a different
kind of subject and it takes
more background preparation.
So those ideas are then
subjected to rigorous tests,
and the ones that remain
standing become what we call
science.
 
So the importance of new
scientific ideas--gosh,
I went through and I managed to
change everything,
but I didn't manage to change
this one thing.
And I have one or two minutes,
so I think I can change it;
I'm going to just pull up that
last line.
What's important and what's not
important?
Well something is important if
it changes a big chunk of our
view of the world,
and it's not so important if it
changes only a very small chunk.
 
So the bigger the change to the
way that people think about the
nature of reality,
the more important the idea.
Next time I'm going to talk
about ecology;
we'll start into that.
 
The rest of the course is
ecology and behavior.
And anybody who would like
lunch today, that's possible.
