Philosophers like to quarrel about things, 
many different things.
They often have opposing opinions
on pretty much everything. But what they
often debate is not the answers
themselves. Very often you find them
quarreling about the questions,
meaning which of the two questions we
are supposed to discuss. So today is one
of those cases when you have some
philosophers saying "Well, No!
This is the question we have to discuss!" And others are saying, "Well, your question
doesn't make any sense!" And then they say, 
"Well, you don't have to discuss that question.
The real question is this one!" So today
is one of those cases. So this is where
we currently are: The  history of
science knows many many episodes when
a theory that was accepted for a very long
was eventually abandoned. The best
example would be probably geocentric
astronomy which provides you a very good
example - a theory accepted for about two
thousand years and then abandoned.
We know this - this is a historical fact.
The question is: given that even
time-honored theories become rejected, can we still claim that our current theories
succeed in describing the world? This is
the question: do our best theories
succeed in describing the nature of
mind-independent world? I'm going to explain the question. Here we have things as
they exist independently of the human
mind - you are familiar with the diagram!
And here we have things as they appear
to human minds in experiments and
observations. And finally here we have
accepted theories. Now you have two
options: Do our theories describe things
as they actually are, here,
independent of our experience? Is this
what our theories try to describe?
Or do they only describe things as they 
appear to us in our experiments and
observations? You have two options: Do our theories describe things as they actually
are - the independent world, the mind-
independent world out there? Or do they
only describe things as they appear to us?
This is  how most philosophers approach the question nowadays. This is the question
they like to discuss. If you say yes
that our theories actually
succeed in describing the nature of the
world that is out there and not merely
our sensations, not merely our experience -
if you say yes, this is the position that
we nowadays called scientific realism.
Scientific realists believe that our best
scientific theories correctly describe
the nature of the mind-independent world.
The opposite view would be called
scientific anti-realism.
Pay attention to their thesis:
they do not say that our theories
fail to describe the nature of the
mind-independent world. That's not what these
guys say. They say that we're not in a position to know whether our theories succeed or
whether they fail. You see the difference
here? They don't say that our theories do
not describe anything out there and they just describe our experiences. That's not what
they say. They say that theories describe
our experiences and as far as the
external world is concerned,
we just don't know.
OK? If you are a scientific realist, then
for you two concepts should be separated:
acceptance and use. On the one hand, you
can say "Well, you know what, I use
the theory in practice." But you can also say,
"I accept these theories as the best
available descriptions of reality."
So for you it is possible to accept some
theories and use some other theories.
So you have this distinction if you're a
scientific realist. On the other hand, if
you are a scientific anti-realist,
you can't really "accept" things - you can't
really believe that any of your theories
provide any description of the world, so
the only thing that remains for you is
to use your theories. So for you, all of
the science is just a nice calculating
tool. Thus the alternative name is
instrumentalist. Instrumentalists believe
that all the sciences just a useful tool
for practical applications.
You understand the difference between the
two conceptions here? Is it clear?
Very good! Scientific realism we're
talking nowadays
in the 21st century has two major flavors:
structural realism and entity realism.
The sign here is a symbol of
generalization which means that these two
are sub-types of this one. So you have
scientific realism divided into two
different versions - at least two different
versions and in fact there are many more.
We start with the structure realism. This is what
they say: they say that although our theories
about the nature of unobservable
entities are strictly speaking fallible, our
knowledge of the relations between
entities is true. So this is what they
have in mind. Here you have the entities
and here you have the relations. What
they say about
our knowledge about unobservable
entities like molecules, electrons,
protons, quarks, and leptons? This knowledge is
fallible. This knowledge is changeable.
It changes with time. What remains
unchangeable, what persists through
changes is our knowledge about certain
relations between those entities and
this knowledge is normally summed up in
our equations. It's the equations that survive.
Alright? So our knowledge about entities
will change because it's fallible.
What will remain is our
knowledge about structures -
relations between things. What they have
in mind is something like this:
although in the future of theories may
be rejected, most of the equations will
maintain their places in the mosaic. Just
like the law of gravity: you may switch
from Newtonian theory to general relativity but
the idea that there is this relation
between different entities in the
universe  will maintain its place in
our mosaic. Another example is the law
of refraction for optics. This law has been
proposed in the 17th century. Since then
we've been through at least four
different optical theories. We have
corpuscular optics, we have wave optics.
And if we put them together, we have
contemporary quantum theory of light.
But this equation or something similar
to this equation has been in the mosaic
all the time. You see? Our knowledge,
our understanding of the nature of
light changed but this relation
has always been there. So this is the
idea: our knowledge of entities is
changeable but structures remain. Is it clear?
We have a question here.
(Student) "How can the equations stay the same if we
think it's acting in a different way?
Doesn't the equation take into account
how we think and act?" (Hakob) The champions
of this theories reply to your comment
that "of course equations must change as
you introduced new entities, but what
remains is some sort of a structural
similarity between different equations."
So probably one of the theories
would signify one thing and the other
theory would signify something different, but
essentially there would be some
structural unity that will remain. So on the
surface this is a very simple idea -
entities change, relations remain. But when
you get to the details, it's not as
straightforward as you may think!
So what's the opposite view? It is
entity realism. They think
exact opposite. They say, "No, it's the knowledge
of relations that is changeable." So
what happens in science is that we discover
newer and newer types of behavior, newer
relations. What  remains unchangeable his
own knowledge of entities. So once
discovered, once established, the entities
will remain in the mosaic forever.
It's like this: Our knowledge about relations
between entities is fallible but our
knowledge about unobservable entities is true.
What normally they have in mind
are things like molecule. Once discovered,
they say, can you imagine chemistry of the future
that doesn't deal with molecules?
Probably not, they say. Other examples
are atom, proton and quark. So these guy's
believe that it's the entities that will
remain. We may or may not learn new
things about these entities, we may for
instance one day learn that there
is this relation between a proton and
a neutron that we weren't
aware, but the entities themselves will remain.
You understand the difference
between the two conceptions here?
Very good! The problem is: no matter which one
of these two your pick, you end up in
trouble. There is a serious problem here. Let's
start with the structural realism. If you
know some history of science, it shouldn't be
very difficult for you to see that our
knowledge of relations is actually
changeable. It is not something infallible.
Take a timeline. Let's go back to the
early 17th century Aristotelian physics.
Let's consider a simple case. We have
here a Roman archer - I don't know why he is not
Greek, probably because I was too lazy
to paint a Greek one -
The theory says you have
applied force here and you
have a certain medium - in this case,
the air that has a certain resistance.
And the arrow moves with a certain
velocity. The theory says that if the
force here is greater than the
resistance of the medium then the object
will move and the velocity will be
proportional to the force and inversely
proportional to the resistance.
Basically the greater is the force,
the greater is the velocity, and the greater
the resistance the smaller is the velocity.
This is the idea. Let's sum it up here.
This is the first question: whether the
force is greater than the resistance?
If it is greater then the velocity would be
proportional to the force and inversely
proportional to the resistance.
What about the case when the resistance in
general is greater than the applied
force? What will happen
to the object? You want it
move but it won't move. In simple English, if
the force is greater than the resistance,
then your object will move with a velocity
proportional to the force and inversely
proportional to the resistance otherwise
the object won't move.
This was their law of violent motion.
Compared this with the Newtonian law.
The same situation in Newtonian physics:
the same archer, and you have the mass of the 
arrow - this now becomes an important variable,
you have a net force which would include
this force, the force of gravity and
everything, right?
And then you have acceleration, not
velocity but acceleration. So what Newtonian
theory tells you - it says the
acceleration of the body is proportional
to the net force and inversely
proportional to the mass. So the equation
is completely different. Not only the
equation but the meaning is different.
Aristotelians believed that the
force is proportional to velocity.
Newtonians think force is proportional to
acceleration, not velocity. It's the change of
velocity per unit time. It's a different
idea. Can you really say that
we maintained any part of the equation?
Probably not. There would be too much of
an exaggeration to say that. Take another
example: compare the classic law of
gravity with its rough equivalent
nowadays, general relativity or
field equation. I'm not going to explain anything
here. Just have a look. If anyone claims
that these two have any structural
similarity, I will say "Well, not really!"
Not only are they mathematically different,
not only do they look different, appear
different, but they convey different
meanings. In this case you have an
equation that connects any two objects
with the mass in the universe. And here you
have an equation that gives you the
value of a curvature of every point in
space-time continuum, so  this point is
curved this much and that point is curved
that much. Two completely different ideas!
There is no attraction in this equation.
Nothing like that. We have to conclude
that the history of science says
that our knowledge of relations is
changeable. Structural realism is wrong
and it has to go because our knowledge
about relations is not immune to change.
What about entity realism? Can we really claim
that there are certain entities that
maintain their positions in the mosaic
despite the underlying changes and
theories? You see the question?
Let's have a look! Again we have to go
and consult history. In the mid 18th century,
there was a phlogiston theory,
the process of combustion. If you asked
specialists in the mid 18th century,
this is how they would explain the process,
they would say "Well, what you have here is a
certain substance which is combustible,
and it burns because it contains a certain
substance called phlogiston, you can call it
a "principal" and there is pholgicston in it.
So what happens? When burning, the
substance is being de-phlogisticated
and the air becomes phlogisticated, so
phlogiston moves from the burning substance
to the air and that's why some
subsistences are combustible while others
are not combustible. So in combustion a
burning substance becomes de-phlogisticated
while the air absorbs phlogiston here 
and turns into phlogisticated
air. Pay attention to the names of
the entities: phlogiston, phlogisticated air,
de-phlogisticated air. What about the
contemporary view on the subject? You all
know this one: we have here a certain
combination of carbon, hydrogen and
oxygen - I don't know what this
combination is because we are not
really interested - and we also have some
oxygen in the air and what happens is
it turns into a carbon dioxide and vapor.
This is what we have. So chemically
speaking in combustion substance
composed primarily of carbon, hydrogen
and oxygen combines with the oxygen in
the air and the products of the reaction
are carbon dioxide and water vapor.
You see how different the explanations are?
One more example. Consider the Aristotelian
elements, the four elements. And then
compare those elements with the elements
of our standard model. This is probably
the most straightforward example.
But if anyone tells you that the
entities that we believe populate the
world survive, then what about this?
Did any of them survive? Not really, they didn't.
This is what we believe exists in the world, not this.
One way of bypassing this problem would be
to say the real science began sometime
in the 18th century. Everything that
happened before that doesn't really
concern us - that's not real science. But that
would be extremely anachronistic,
wouldn't it? If we choose that path, we
have to be absolutely prepared. Future
science will take the scissors and cut
us out of the picture if we cut out 
the science of the past
of the picture then we have to be
prepared that we are going to be
dismissed as well! Are we ready for that?
This example shows that entity
realism is no good. It's no good because
entities are also changeable. Not the
entities themselves, I mean our knowledge
of entities, you understand? So what do we do?
Structural realism is no good because it
assumes that our knowledge of relations
is unchangeable. This is not good.
This is incorrect.
Entity realism assumes that our knowledge
of entities is unchangeable and this is
also not good. This is also incorrect.
So what's wrong here? Why do they both fail?
They fail because they both represent
a wrong-headed approach, a selective
approach, which is: "Although strictly
speaking all our theories are false,
some aspects of our theories are true."
They both exemplify this approach.
selective approach. What they try to do
basically is to take the theory and say
"Well, yes all together it is false but
some parts of it are true." Basically
they're trying to distinguish between
true propositions in the theory and false
propositions in the theory. You see what
they are trying to do? Some propositions are
true, some propositions are false.
Why do you think this is bad?
Any ideas? You know enough philosophy of
science to be able to answer this question.
What's wrong with the selective approach?
It is also called selective skepticism or
selective optimism. It comes with different
names.
But essentially they share the same idea that
parts of the theory operate while others
are fallible. If I can't even say here in
the 21st century that I believe that
some propositions are immune to change.
How would you react to that? What's wrong
with this approach? (Student) "Wouldn't 
that kind of belief be based on
infallibilism which isn't generally accepted 
anymore?" (Hakob) That's the point! If you
say "Yes, all theories are fallible
and yet some parts of our theories are
infallible. Basically what you're saying
is that you can have absolutely certain
synthetic propositions.
Not all of them are absolutely certain
but some of them are. Either those
describing entities or those describing
structures but some of them are
infallible. That's what you're saying. And
many of the philosophers don't realize
that when they talk about these things
and then you discuss this with them and
said "listen, what you're saying is
basically you are going against the idea
of fallibilism. It's the fallibilism
that's accepted nowadays, right? We
believe that any synthetic proposition,
any hypothesis about the world, be it a
hypothesis that concerns structures or
entities or anything, is fallible,
meaning not immune to change, right? I
think we have established this. We have
established this in Lecture 2. If the
question is what's wrong with the
selective approach, this is what's
wrong with it!
It contradicts the position of
fallibility which is nowadays accepted.
And that's the reason why it has to be
abandoned. So you cannot really take a
theory and separate its true
propositions from its false
propositions. Its not going to happen
because all of your empirical hypotheses,
whether they concern entities or
structures, all of these hypotheses are
fallible. And you have to accept that. You
cannot hope that you have a secure place
in your theory that is beyond any doubt.
You can't have that. So what do you do?
What do you do if you are fallibilist?
If you are fallibilist, if you really
appreciate the fact that every
hypothesis is as fallible as anything else,
if you really understand this, and the
only thing that you can hope to achieve
is to know whether your current theories
are closer to the truth than the theories
of the past. So it's not a question
whether your theory is correctly
describing or incorrectly describing
the world. As far as the previous question is
concerned, the answer is simple: yes, they
roughly describe the world but we can
never know the degree to which they
describe the world. End of the story.
The question that we're really
interested is the question of scientific
progress.  I'm going to explain this.
So the question here.
"Do scientific theories correctly
describe the external world?" is a wrong
question. The right question is this one:
"Does science actually progress towards
the true description? In other words: Is it true
that our current theories are only
slightly better in describing the world
than the theories of the past? So what we
want to know is whether there has been
or is any scientific progress? Are we
moving in the right direction? You see
the difference here? This question doesn't
assume that any part of our theory can
be absolutely true. It doesn't assume. And yet
we want to know whether we are moving in
the right direction.
The reason why this is important is
because we happen to believe that unlike
many other fields of human endeavor,
science is almost unique in a sense that
a notion of progress can be properly
applied to science. If you consider other
fields of human endeavor, say art, sport,
or anything really, you see that the
notion of progress is really
questionable. I'm going to give you some
examples. Progress in music: let's take
this "boy band" (The Beatles) here,
and this band here. Can anyone in a sober mind
really argue - unless you're 13
and have never heard anything by the Beatles -
I'm not claiming that one is better than the other -
I'm not claiming that. I think we can all
agree that the notion of progress as far
as boy bands are concerned is really
questionable. Can we all agree on that? OK!
Take rock music - this was the music of my
time when I was a kid (Queen),
Freddie Mercury was everything. His death
was a huge huge thing. I was only
12 years old and it was
terrible. But this is the music now (Coldplay).
Is this the best we have?  Again, no offense.
I like your music but can anyone claim
that these guys here have anything
remotely as good as Bohemian Rhapsody?
Probably not. Again let's just appreciate the 
fact that not one is better than the other -
that's not what I'm claiming, OK? Don't go
and tell your friends that you have to
listen to Queen because Hakob says Coldplay 
is rubbish. That's not what I'm saying.
I'm just saying that the notion of 
progress here is questionable.
Those of you know about these things can
say "Hakob, who cares about pop music?
Let's go and compare the real
music, classical music!"
Ludwig van Beethoven.
Have you ever heard of this guy?
Pierre Boulez.
I had a girlfriend once
- this is not the same from last week -
this one was an actual professional
musician and she actually was trying
to convince me that whole history of music
is a progression from simple forms
to more complex and complex forms, like  from 
simple unison singing to polyphonic singing
(different voices) to harmonies and then
you get all the way to the contemporary
classic music when everything is atonal -  do you know what "atonal" means?
There is no key. That's what it means.
There's no key.
Go to YouTube and try to listen.
Pierre Boulez.
She was honestly trying to convince me, that this guy is our contemporary Beethoven.
Again, I'm not saying anything but I think we can all appreciate
that the notion of progress in music is problematic.
Can we all agree on this?
Unless you're going to apply the famous formula which Mark Twain said about Wagner's music.
He said, "Well, you know what, his music is actually much better than it sounds."
OK, what about visual art? You say, "Well, OK! Forget about music, with visual art we
have progress! After all we started from
something like this and then we moved on
all the way to you know something like
that to which I can say "What, you
remember what happened after ... you have this
Expressionism! And then you have all
sorts of cubism and stuff and then
things like that and all the way to this.
I think it's agreed among professionals
that as far as visual art is concerned,
we don't have really progress from worst
to better. What we really have is a
proliferation of different forms,
different techniques. So if there is any
progress, it is in a sense of creating
new forms of approaching the subject.
Essentially this is the idea. But as far
as the progress from "not as good" to
"slightly better" is concerned, we're not
really in a position to say that. So the
notion of progress is also problematic
in visual art. What about football?
When I say football I mean the game
98% of the world calls, football - you have 
to use the name properly - this one is
actually played with the ball and feet, right?
I'm not saying that I like this one
better than American football. Pele is
better than Maradona? Or is Maradona better
than Pele? Or is Messi better than Maradona?
The point here can be also applied
to any sport. The notion of progress is
really problematic. If you don't like
this you want to discuss American
football. That's fine too.
Is Peyton Manning better than Tom Brady?
Well it depends on how you look at those
things. If you count the Super Bowls, then 
Tom Brady is superior. But if that is
your strategy then even Eli Manning
would be better than Peyton Manning. Am I right?
Now, can we all agree that in many fields
of human endeavor the notion of progress
is problematic? Science, on the other hand,
seems to be that unique field of human
endeavor when we seem to be in a
position to apply the notion of progress
and claim that our contemporary
theories are at least slightly better
than the theories of the past. So our
question, our task, is to figure out
whether that is really the case. So here
is the question: Is it true that our
theories simply provide us with 
different pictures of reality,
none of which is better or worse?  Is it
really true? That it's only about
providing different forms just like it
happens in visual art, different ways of
looking at things which is particularly
better or worse, just like here in this
case you have the Aristotelian way of
looking at things - you look at things
from the Aristotelian eyes and see an
object descending towards the center of
the universe and then you wear your 
Newtonian glasses and you see objects
attracting each other with the force of
gravity and then you switch to the
general-relativistic way of looking at
things and you see an object in a state
of inertial motion in a curved
space-time continuum. Is this really what
science is all about? Just providing us
with different ways of looking at things,
just like in visual art? 
Or, can we say that our theories
gradually improve our understanding of
reality by switching from one theory to
the next - we are actually getting better
understanding of the world? So this is
the question. If it is the first one, if
it is all about different forms of
approaching the world, then there is no
scientific progress, and the external world
remains unknown. On the other hand, if 
our theories gradually improve our
understanding of reality, yet never
actually getting there, never actually
achieving 100% certainty - if this is 
actually the case, then there
is scientific progress, and the external world
is knowable, albeit always in a somewhat
problematic sense - never with absolute
certainty! You see the dilemma here?
So this is the question: Does science
actually progress towards truth?
In science, generally speaking, we're trying to
accomplish, we try to uncover the
structure of the world we inhabit.
To that end, what we do? We come up with all
sorts of hypotheses. we hypothesize
the existence of different
forces in order to explain and predict
many physical phenomena.
hypothesize something about the
structure of the world such that this
hypothesis allows us to predict things,
to explain things in the world of
experience, the world of observations
because essentially in the end of the day
that's the only world that we are dealing with.
But in order to explain things that we
see, hear, and taste, we hypothesize some
internal structures. That's what we do.
It applies to every field of science.
The hypothesis of atomic structure allowed
us to explain many chemical phenomena.
We postulated the existence of evolution so
that we could explain biological
processes. And examples are endless.
Take any science and you see that we
hypothesize something to explain the
the world of phenomenon, the world as it
appears in experiments and observations.
OK? Now the question here is: Can we say
that our hypotheses here concerning the
inner structure of the world progress
towards the true structure?
Essentially this is the same question,
of progress. Does science actually
progress towards truth? Yes or no.
If you say yes, this is the Progress
Thesis: science progresses towards truth,
meaning that scientific theories provide
increasingly correct descriptions of the
external world. If you say no. this is the No-
Progress Thesis. Basically it says that we
are not in a position to know whether we
progress towards truth. You have to pay
attention: this is not the same question
as the initial one. The initial question was
whether our best theories provide
us with a correct description of the
world, end of the story. And that
question, as I was trying to argue, is a
wrong-headed question because it is
based on an infalliblist assumption,
the assumption that some parts of our theories
may be absolutely correct. We cannot
accept that question. If you're a
fallibilist, this is the right question
to discuss. This is the question to
address if you're a fallibilist.
This reminded me one more story to tell you.
I met this guy a few years ago. He was in
his early 40s. And he was married to
his fifth wife at the time. I couldn't
help it. I had to ask: "Listen, why bother
really? I mean I understand once or
twice, you know. Made a mistake. But look
what's the point? You really enjoy the
process? I don't know ... the wedding
preparations? Bachelor parties?
What's the point? He said, "No, I actually hate
those things. Not very fun and extremely
expensive." So then what's the point?
Why would you do that? He said, "You see.
I used to believe that they can be such
a thing as progress in marriage.
and I was aiming to make sure that my
next wife is at least slightly better
than the one before." I said, "Any luck?" He said,
"No, not really." Is such a thing as progress in science?
Does science actually progress towards truth?
The first thing to do, you may think "OK, we
have a theory of scientific change. What
does the theory of scientific change
tell us about this whole thing? Let's
consult the theory of scientific change.
Well, if we consult that theory, then we
have to have a look at the 2nd Law which
says if you want to convince the
community you have to meet their
expectations. This is the 2nd Law. Then we
have to take the definition of "acceptance".
What does it mean for a theory to be
accepted? It means to be considered the
best available description of its
particular object. It could be a formal
object or natural object or social object. If
you put those two together then it is
certain that any scientific community is
always going to have a sense of progress.
So if you ask anyone in the scientific
community "What do you think: Is
general relativity a better description
of reality the Newtonian physics?"
Of course, that's the very reason why we
accept general relativity in the first
place. So if you ask anyone within the
scientific community, the answer to the
question of progress is always going to
be positive, right? Because that is the
very reason why would subscribe to the
theories that we subscribe nowadays. If we
don't believe that they are slightly
better than the theories of the past,
we won't accept them. The scientific
community always holds that there is
scientific progress. So if you ask the
community, the answer is always positive.
I'm going to give you a few examples.
Theory and method: imagine an extremely
conservative community that believes
that the Word of God is
the only source of infallible true
knowledge. Suppose, for the sake of
argument, you have this community. If you
accept this, then you're only going to
accept those things which are found in
the word of God. This will be
your method and this is by the
3rd law. But even this extremely
conservative community can actually
manage to learn new things and can
actually manage to change their method.
What if they discover a new fragment of
the Word of God? Let's say a new scroll?
And suppose, for the sake of argument,
it says in the newly found scroll that our
senses are trustworthy for they are
given to us by God so that we could
study the world. But the moment you
accept this, you have to modify your
method. So this is what happens:
First, this belief has to be modified. You
cannot say that the Word of God is the
only source of knowledge. It's one source
of knowledge because now you have
senses too. Now you have two sources:
revelation, the word of of God, and also things
that you learned through your senses.
Make sense? The moment you accept this
new belief, your method changes by the
third law. The theory is acceptable if it is
revealed in the Word of God or if it is
based on observations. Completely
rational transition. Even this
community will necessarily have a sense
of progress. If you ask them, "Do you nowadays
know more than you knew yesterday?"
Of course! That's the reason why we
changed our views. If we didn't believe
that we progress, we wouldn't change our
theories. So essentially this is a very
interesting approach but it doesn't do
much. The problem with this approach is that
it seems to be question-begging. It is a
question-begging approach because both
of these propositions, both of the
premises, are true by definition.
This is the definition of acceptance and
this one here follows from the
definition of employed method: you
remember that the 2nd law was a tautology?
So if you put two tautologies together and 
solve a problem, well, that's a very cheap
solution because the question is not
what scientists themselves think about
progress. They are always going to say
there is progress because of this thing.
The moment they switch from theory A to
theory B, they are going to believe that
theory B is a better description of 
the world than theory A.
Otherwise they wouldn't switch to theory B.
So this true by definition. Ask any scientific
community and they will believe 
that there is progress.
So the question is not what scientists
themselves think about the process but
whether they actually succeed in
approximating the true. That's the
question. For this. you have to find
some other approach. It is a historical
fact that science has been empirically
successful. We can all agree that as far
as the predictive power of science is
concerned, there has been an
unquestionable progress. So if you
compare science of the 21st century with
the science of the 17th century,
it is unquestionable that we are capable
of predicting more, doing more things, our
predictions are much more accurate and
precise. So as far as the world of phenomena
concerned, there is no question
that are predictions become more and
more precise and more and more accurate.
But this is not the question. Nobody denies
that there has been a serious progress
as far as our description of phenomena
is concerned. The question is whether we are
getting closer to the true picture of
the world as it really is out there.
So the predictions of our theories become
increasingly precise and accurate.
By advancing new hypotheses
about the inner structure of the world,
we gradually increase our overall
predictive power. We hypothesized
the existence of curved space-time
continuum and we predicted many
astronomical phenomenon, we hypothesized
neurons and then we predicted and explained
many things in the brain. The number
of phenomena that we are able to predict
and manipulate constantly increases.
But the world of phenomena cannot be
altogether unconnected from the external
world. So the argument goes: if you
actually manage to explain things as
they appear to you, you also realize that
these appearances here cannot be
altogether unconnected from things as
they really are. The results of
experiments and observations are at
least partially affected by things as
they really are. Do you agree on this?
That there's some connection between the
two worlds? As long as you believe that
there is an external world that affects
your senses, you also have to appreciate
that there must be some connection
between things as they really are
and things as we perceive them. Therefore
you have to accept explanations
provided by theories make progress in
the direction of the truth. So as our overall
predictive power increases, generally
speaking, this will be a good indication
that we are actually progressing in the
right direction. So this is the argument:
Science has been empirically successful.
And by empirically successful we mean
predictions of our theories become
increasingly precise and accurate.
So when it comes to experiments and
observations and things that we actually
observe, we get increasingly accurate and
precise. On the other hand , we also accept
that reality effects phenomenon, that
there must be some connection between
the world of phenomena, the world of
experiments and observations and somehow
affected by the external world that it
is not a complete the illusion,
that something from the outside affects us. 
You put those two together and you've
arrived at the thesis of progress,
progress these. Science has been
progressing towards truth. Explanations
provided by scientific theories are
increasingly correct. The idea here is
very simple: if this were not the case,
then the empirical success of science
would be just a miracle. If we somehow
manage to predict more things,
manipulate more things, and yet
it didn't tell us anything about the world
as it really is, that would be just a
miracle. The only way to explain why is
it that we are so successful in our
predictions is to appreciate that we are
actually moving closer and closer and
closer to the correct description of the
world, generally speaking. That's the name
of the argument: the no miracles argument. This 
is nowadays one of the major if not the major
argument for the thesis of scientific
progress. The argument says: since our
theories become increasingly accurate
and precise in their predictions, this
can only indicate that we gradually
uncovered the inner structure of the
world. So the fact that we explained this
and managed to manipulate it, says that 
we are getting something right.
Even without our Aristotelian physics, 
we proceeded through Newtonian and
Einsteinian. This is the idea. Now what can
a champion of the opposite view, one who
denies the existence of scientific
progress, reply to this? A champion of the
opposite view will say, "Well, this is all
very interesting. But you forget about
something extremely important. And that
important thing is the fact that we
constantly make mistakes when it comes
to our ontology." What is ontology?
Ontology is just our views on which
entities and relations populate the
world. That's ontology: what constitutes
the world. Take a timeline. These are your
Aristotelian elements in the 16th century. In the
middle of the 18th century, you have
your phlogistic chemical system. You 
find phlogiston here. There it is!
And then you take a more
contemporary view on the subject.
You have contemporary chemistry. Now it
is a historical fact, they say, that our
knowledge about the entities that
populate the world changed through time,
that we often get wrong when it comes to
our ontology. We just abandon those
ontologies. So the question is: if the
ontologies of past theories are normally
considered mistaken from later perspectives. 
How can we claim that we
move towards the correct ontology, since 
that is the essence of the progress:
that you move towards better and
better understanding of the actual
structure of the world. So this is the
argument: the ontologies of past theories are
usually considered mistaken from the
perspective of later theories. And this
means that the same fate
most likely awaits our contemporary
theories and ontologies there are
implicit in our contemporary theories,
On the other hand, the definition of
progress assumes that it is a process 
of acquiring increasingly correct
descriptions of the world, including its
ontology. You put those two together and
you arrive at the No Progress thesis,
which says that we can't know whether science
progresses towards truth, whether some
descriptions are closer to the truth
than others. So this is the argument: the
idea of progress, they say,
assumes that ontology implicit in our
current theories are more correct than
those implicit in theories of the past.
But the history of science, they say,
shows that ontological elements come and go.
Observe this: we used to believe in the
four elements, then we have the
phlogiston system of chemistry and nowadays we
have a periodic table, elements come and
go, they say. If this is the case, it is
most likely, they say, that in the future
our current ontology will be considered
mistaken and therefore there is no
actual progress towards truth. Just
different approaches, different views on
the subject. And different descriptions
of the process can increase the overall
predictive power but they do not take us
closer to the truth and this becomes
very similar to what we have in Visual
arts. This view basically tells you that
we proliferate different forms of
approaching the world and none of them is
particularly better, none of them is
particularly worse. So this is the argument.
What do you think about this?
(Student) 'This completely ignores the
fact that new theories are better at
predicting things. It's just says 'well. if
it doesn't hold true for every single
case it's no good than the last one.'
Why is it ignoring the fact that it is
better than the previous theory?"
(Hakob) Do you think that what Miriam says is true? 
That this argument really ignore the fact that new
theories are actually better in dealing
with the world of phenomenon, the world of
observations and experiments? (Student) "I think
what they're actually talking about is
the depiction of the entities within a
world and the accuracy is kind of not
attacked here in this argument. It's 
kind of separate from the entities."
(Hakob) Denis is absolutely right! Let's get 
this one straight. Two different issues here.
One is whether our new theories are more
precise and more accurate in their
predictions and nobody says "no" to this
because it's just the basic historical
fact that they are, OK? Nobody questions
that we become increasingly accurate and
precise as far as the world of practical
applications and the world of the phenomena is
concerned. So from the purely technological 
standpoint: of course there is progress.
Even the champions of the No-Progress
thesis would never deny that.
They all agree that there is technological
progress. The question that separates the
two parties is whether by getting more
precise and more accurate we also
approach the true description of the
world as it really is. So this is the
question. And these guys only 
deny that we are in a
position to say that our current
theories are actually better
descriptions of the world than theories of 
the past. (Student) "So basically are they saying
there's no progress because every time
we use another theory in place of the
last one, it's basically taking us back
to zero, it's basically saying what we
knew is no longer existing so we are 
now starting from ground zero."
(Hakob) Essentially that's what they
say! They say, "See, not only theories become
rejected but also ontological elements
implicit in theories become
rejected  altogether. This is what the
history of science teaches us and this
is really disturbing! Consider the
argument and read what they say. They say
ontologies of past theories are usually
considered mistakes, meaning that any
moment of time you have a whole
graveyard of rejected ontologies -
just one false ontology followed by
another false ontology and another false
ontology. You see what they say? 
This is the picture that
they have in mind.
False, false, false, false, false ... and the
current one which I think is more or
less true but then that one becomes
false too. So essentially if you look at the
history of science, it is just the
succession of false ontologies. You see
their point, the point they are trying to make?
(Student) "Unless we're resurrecting something,
then as the graveyard fills up we're
eliminating possibilities. So isn't that
a progression itself?" (Hakob) This is very 
much in tune with Thomas Edison would say.
You remember what he said?
"I didn't fail. I found 10,000 ways in
which it didn't work." But essentially
doesn't really put you in a position to
say that you are getting any closer.
You just know the 10,000 that didn't and
then maybe there are 10 million trials.
If it's true that the number of possible
ontologies are limited, then your argument
would stand. But here the number
of possible ontologies are infinite so
what does it give us? 
Another piece in a graveyard?
(Student) "Isn't the basis of the No Progress
thesis based on flawed induction which we saw
in previous lectures? Just 
because past ontologies have
proven to be flawed, it doesn't mean that
we can deduce that future ontologies
are going to be flawed?" (Hakob) That's a very 
good question! Now pay attention to the name.
It is called "pessimistic induction" or 
more properly "pessimistic meta induction".
The reason why this is called
induction is because we base our
prediction of future possibility of our
current ontology to be rejected on
past rejections. We say, "Well, in the past
this is how it has happened. We had a
theory that was accepted and then the
whole ontology of the theory was thrown
away and then that happened with the
second theory and the third theory!
Now we have this theory here which we
believe has good chances to be rejected too,
why not? So in a sense this is inductive, hence 
the name. But I think a case can be made
that the same premise here can be also
justified without any use of induction.
The main theoretical reason 
why we nowadays believe that our
theories have a serious chance of being
rejected in the future is based on our
fallibilism. It is because we are
fallible, not because of the history
of science, not because of the track
record of graveyard, not because of that!
Or rather, not merely because of that, but mainly
because of the fact that we know that
our theories are fallible. And as a
fallible theory it has a very good
chance of being replaced by something
else, right? So, even though in literature
this argument is called 
"pessimistic meta-induction",
I think it can be formulated in
such a way that it avoids the use of
induction.  (Student) How much can we 
separate or divorce ontology from
predictive laws and theories? I
don't know a lot about ontology but
aren't they so closely linked that you
can say "Well, theories and laws progress,
and ontology just follows it or ontology 
is just the child of theories and
laws so it should also progress?"
(Hakob) These guys here in the No-Progress camp
essentially separate the
predictive power from the ontology.
Isn't it the case that the equations of
the theory that are meant to predict
things actually connected to the
ontology that comes with it? So you can't
really have one without the other. 
That's your question, right?
It's a historical fact that the same phenomenon
was very well predicted by many
different theories. Astronomical theories
are a very good example. You know you had
your Ptolemaic astronomy, the geocentric
astronomy, and then you had your
heliocentric astronomy - all predicting 
the same phenomena.
Completely different ontologies. So their
structures of the world were different and
yet they predicted the same visible effects. 
Let's take another example, the one
that you know: falling apple. The same
phenomenon can be predicted by Aristotelian
physics, Newtonian physics and
general relativity which as you know
come with completely different ontologies.
So it is possible for two theories to
produce exactly the same predictions and
yet postulate completely different
structures of the world. You remember
last time we covered the principle of
complexity that is implicit in our
contemporary science which is the idea that
there is more to the world than what meets 
the eye. And there was a second principle,
the possibility of post hoc explanations
which is the idea that any phenomenon
can be given many different contrasting
explanations. This is basically the idea.
You can have exactly the same prediction
from two theories that have nothing in
common when it comes to their ontologies.
And we had that! The best example
nowadays is the so-called
interpretations of quantum mechanics
which are not really interpretations but
different theories, if you think about it! 
They have exactly the same predictions.
They reproduce the predictions of the
accepted orthodox quantum theory, and yet
they postulate different ontologies.
They come with different ontological
elements. This is one of the reasons
why the champions of this view say,
"Well, you know what, you can have the same
predictions with different ontologies,
then why bother?
What makes you think that this ontology
is better than the other one, right?
If you can have the same prediction, how do you
choose over competing ontologies?
(Student) "Our theories are getting 
at predictions, right?
But you're saying that two 
theories can have
completely different ontologies but
predict the same thing like in the case
of the falling apple and relativity
but we accept relativity because
it predicts certain things that Newtonian
physics can't. That's why we accept
relativity. So in that case is
the ontology that is associated with
the better theory better?"  (Hakob) I for one
agree with that! But then the champions of
pessimists say "Give us any set of
prediction and we can give you the same
exact predictions with a completely
different ontology." You see that's their point.
We know that this is possible
because we know about the possibility of
post hoc explanation, that after the fact
you can explain anything in any possible way.
Think astrology: after the fact, 
everybody is smart. So the debate can
go on for ever. And yet I believe there
is a way to untangle this conundrum.
This is what I suggest: I think there is
something extremely wrong with the way
this argument is constructed.
Pay attention to the way they formulate this.
The way we define progress: we do not
think that our current ontology 
is absolutely correct.
Merely it is a better approximation
than the ontologies of the past.
Can you all agree on this? This is not very
contentious. I think this is clear.
If you are fallibilist, you believe that
your current ontology is slightly better
than the ontologies of the past - again
never absolutely correct.
Is it clear? If this is so, then we can't say
that past ontologies were absolutely false.
So there is no such thing as a graveyard
of false ontologies. If you're a fallibilist,
strictly speaking you have to 
say that the ontologies of past
theories are not as good as our current
ontology, right? If there is no absolute
truth then there's no absolute falsity, 
right? Two sides of the same coin.
If you say that your current
ontology is only slightly better than
the ontology of Newton and Newton's
ontology is only slightly better than the
ontology of Descartes and Descartes' 
ontology is slightly better than the
ontology of Aristotle, it means that
those ontologies are not absolutely
false. Merely they're not as good as
our current one. We do not believe that we
commit ontological mistakes. Quite the
opposite, we believe that we commit
ontological progress and that we are getting
better and better than the previous ones.
They are not rejected in a sense that they
are considered absolutely false. They are
rejected because we believe we have
something better. We do not believe that
Newton was absolutely wrong, just like we
do not believe that Aristotle was
absolutely wrong with this four elements.
We believe that there was some rational
content in that. The fact that there are
liquids and solids and gases and fire -
they got something right. We no longer
believe that there is an element earth,
element water, element fire, element air, but
there is some true content in that.
Nowadays we do not believe in the idea
of the graveyard of ontologies!
We believe in a succession of ontologies 
where every future ontology tries to
improve on the ontology of the past.
Therefor this thesis -  the premise of
ontological "mistakes" - is wrong.
And the whole argument is flawed, OK? Very good!
Let's sum it up. So this is the problem:
the progress thesis. The major argument 
for the thesis is No-Miracles Argument.
And here the major argument is
the Pessimistic Meta-Induction Argument.
Nowadays we have reasons to believe that
this argument is flawed because it is
based on a wrong picture of science: on
the idea of graveyard of false
ontologies which we don't is the 
case. If this is the case then I think we
can tentatively say that there 
is scientific progress, although we
also have to appreciate that the
question is far from settle. Consider
this Hakob's position, but you can't say 
that this is accepted view. As far as
this question is concerned, there is no accepted 
view. It's an open question that is debated
among philosophers, OK? Very good! 
Next time, my favorite question of all:
What's the difference between science and
pseudoscience, and non-science, after all?
Is there such a thing that makes
something a proper science as opposed to
all those pseudo-scientific exercises? 
I'm going to talk about this next time.
Thank you very much!
