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your most recent book titled Einsteins
unfinished revolution so I have to ask
what is Einsteins unfinished revolution
and also how do we finish it well that's
something I've been trying to do my
whole life but Einsteins unfinished
revolution is the twin revolutions which
invented relativity theory special and
especially general relativity and
quantum theory which he was the first
person to realize in 1905 that there
would have to be a radically different
theory which somehow realized to resolve
the paradox of the duality of particle
wave for photons and he was I mean
people I think don't always associated I
started with quantum mechanics because I
think his connection with it founding as
a one of the founders I would say of
quantum mechanics he kind of put it in
the closet is it well he didn't believe
that the quantum mechanics as it was
developed in the late 19th middle late
1920s was completely corrected first he
didn't believe it at all then he was
convinced that it's consistent but
incomplete and that also is my view it
needs for various reasons I can
elucidate to have additional degrees of
freedom particles forces something to
reach the the stage where it gives a
complete description of each phenomenon
and as I was saying realism demands so
what aspect of quantum mechanics bothers
you and I Stein the most is it some
aspect of the wavefunction collapse
discussions the measurement problem is
it the the the measurement problem I'm
not gonna speak for Einstein but the
measurement problem basically and the
fact that what is the measurement
problem sorry the basic formulation of
quantum mechanics gives you two ways to
evolve situations in time one of them is
explicitly when no observer is observing
or no
taking place and the other is when a
measurement or an observation is taking
place and they country they basically
contradict each other but there's
another reason why the revolution wasn't
completed which is we don't understand
the relationship between these two parts
general relativity which became our best
theory of space and time and gravitation
and cosmology and quantum theory so for
the most part
general relativity describes big things
quantum theory describes little things
and that's the revolution that we found
really powerful tools to describe big
things and little things and it's
unfinished because you wouldn't have two
totally separate things and we need to
figure out how to connect them and so it
can describe everything right and we
either do that if we believe quantum
mechanics as understood now is correct
by bringing general relativity or some
extension or general relativity that
describes gravity and so forth into the
quantum domain that's called quantized
the theory of gravity or if you believe
with Einstein that quantum mechanics
needs to be completed and this is my
view then part of the job of finding the
great completion or extension of quantum
mechanics would be one that incorporated
space-time in gravity so where do we
begin so first let me ask perhaps you
can give me a chance if I could ask you
some just really basic questions well
they're not at all the basic questions
and the hardest but you mentioned
space-time what is space-time space-time
you talked about a construction so I
believe the space-time is a intellectual
construction that we make of the events
in the universe I believe the events are
real and relationships between the
events which caused which are real but
the idea that here is a four-dimensional
smooth geometry which has a metric and a
connection and satisfies the equations
that Einstein wrote it so
good description to some scale it's a
good approximation it captures some of
what's really going on in nature but I
don't believe it for a minute is
fundamental so okay let's we're gonna
allow me to linger on that so the
universe has events events caused other
events this is idea of causality okay so
that that's happy let's in my in your
view Israel or hypothesis so the
theories that I have been working to
develop make that assumption is so
space-time you said four-dimensional
space is kind of the location of things
in time is whatever the heck time is and
you're saying that space-time is both
space and time are emergent and not
fundamental no sorry
before you correct me what is it mean to
be fundamental or emergent fundamental
means it's part of the description as
far down as you go we have real yes as
real as real it could be so I think the
time is fundamental and quote goes all
the way down and space does not and the
combination of them we use in general
relativity that we call space-time also
does not but what is time then I think
that time the activity of time is a
continual creation of events from
existing event so if there's no events
there's no nothing
then there's not only not no time
there's no nothing so so I believe that
history universe has a history which
goes to the past I believe that a future
does not exist there's a notion of a
present and a notion of the past and the
past consists of is a story about events
that took place to our past
so you said the future doesn't exist yes
could you say that again can you try to
give me a chance to understand that one
more time so what the events cause of
their events what is this universe
because we'll talk about locality in
nonlocality
good because it's the crazy I mean it's
not crazy it's a beautiful set of ideas
that you you proposed but and if
causality is fundamental just like to
understand it better what is in what is
the past what is the future what is the
flow of time even the error of time in
our universe in your view and maybe it
was an event right Oh an event is where
something changes or where to I it's
hard to say because it's a primitive
concept and the event is a moment of
time within space this is the view and
general relativity where two particles
intersect in their paths or something
changes in the path of the particle now
we are postulating the theories I have
two fundamental level a notion which is
an elementary notion so it doesn't have
a definition in terms of other things
but it is something elementary happening
and it's it doesn't have a connection to
energy or matter or exchange of any ties
to have a connection energies masses at
that level yeah that it involves and
that's why the version of a theory of
events that I've developed with Marina
Cortez and it's by the way I want to
mention my collaborators because they've
been at least as important in this work
as I have marina Cortes in all the works
since about 2013 2012-2013 about
causality Carlos set and in the period
before that Roberto mangabeira Unger who
is a philosopher and a professor of law
and that's in your efforts together with
your collaborators to finish and finish
so yeah and focus on causality
environmental yes it's fundamental to
physics so and and there's certainly
other people we've worked with but those
two people's thinking had a huge
influence on my own thinking so in the
way you describe causality that's what
you mean of time being fundamental that
causality is from the earth and what
does it mean for space to not be fun
about though to be very good this is a
level of description in which there
events there are events create other
events but there's no space they don't
live in space they have an order in
which they caused each other and that is
part of the nature of time for us so I
but there is an emergent approximate
description and you asked me to find a
version I didn't an emergent property is
a property that arises at some level of
complexity larger than and more complex
than the fundamental level which
requires some property to describe it
which is not directly explicable or
drivable is the word I want from the
properties of the fundamental things and
space is one of those things in a
sufficiently complex universe space
three-dimensional position of things
emerged yes and we have this we saw how
this happens in detail in some models
both computationally and analytically
ok so connected to space is the idea of
locality yes that so we talk about
realism so I I live in this world at
like sports
you know locality is a thing that you
know you can affect things close to you
and don't have an effect on things that
are far away mm-hmm it's the thing that
bothers me about gravity in general or
action in a distance the same thing that
probably bothered Newton or at least he
said a little bit about it
okay so what do you think about
localities it's just a construct is it
us humans just like this idea and are
connected to it because we exist in it
we need it for our survival but it's not
fundamental I mean it seems crazy for it
not to be a fundamental aspect of our
reality it does and you comfort me and a
sort of as a therapist like how do I I'm
not a good therapist okay there are
several different definitions of
locality when you come to talk about
locality in physics in quantum field
theory which is a mixture of special
relativity and quantum mechanics there
is a precise definition of locality
operative field operators corresponding
to events in space-time which are space
like separated commute with each other
as operators so in quantum mechanics you
think about the nature realities fields
and things that are closed in a field
have any impact on each other more than
farther away that's yes that's very
comforting that makes sense so that's a
property of quantum field theory and
it's well tested
unfortunately there's another definition
of local which was expressed by Einstein
and expressed more precisely by John
Bell which has been tested
experimentally and found to fail and
this set up is you take two particles so
one thing that's really weird about
quantum mechanics is a property called
entanglement you can have two particles
interact and then share a property
without it being a property of either
one of the two particles and if you take
such a system
and then you magically make a
measurement on particle a which is over
here on my right side then particle B
which is over here and what somebody
else makes a measurement in a particle B
you can ask that whatever is the real
reality of particle B it not be affected
by the choice the observer at particle a
makes about what to measure not the
outcome just the choice of the different
things they might measure and that's a
notion of locality because it assumes
that these things are very far space
like separated and it's going to take a
while for any information about the
choice made by the people here at a to
affect the reality of B but you make
that assumption that's called bell
locality and you derive a certain
inequality that some correlation
functions of correlations have to
satisfy and then you can test that
pretty directly in experiments which
create pairs of photons or other
particles and it's wrong by many Sigma
in experiment in exact match so what
what does that mean that means that that
definition of locality I stated is false
the the one that Einstein was playing
with and the one the one that I stated
that is it's not true that whatever is
real about particle B is unaffected by
the choice that utility' makes as to
what to measure in particle a no matter
how long they've been propagating at
almost the speed of light or the speed
of light away from each other it's no
matter so like the distance between them
well it's been tested of course if you
want to have hope for quantum mechanics
being incomplete or wrong and corrected
by something that changes this it's been
tested over a number of kilometers I
don't remember whether it's 25
kilometers or 107 kilometers but so in
trying to solve the unsolved revolution
in trying to come up with a theory of
everything is causality
fundamental and breaking away from
locality absolutely fun a crucial step
you so the in your book essentially
those are the two things we really need
to think about as a community especially
the physics community has to think about
this way I guess I my question is how do
we solve how do we finish the end finish
revolution well that's I can only tell
you what I'm trying to do and what I
have abandoned yes not working as one
ant smart ant in an ant colony yep I may
be dumb that's why who knows but anyway
that's become my view of the we've had
some nice theories invented there's a
bunch of different ones both related to
quantum mechanics related to quantum
gravity there's a lot to admire in many
of these different approaches but to my
understanding they none of them
completely solve the problems that I
care about and so we're in a situation
which is either terrifying for students
or full of opportunity for the right
student in which we've got more than a
dozen attempts and I never thought I
don't think anybody anticipated it would
work out this way which work partly and
then at some point they have an issue
that nobody can figure out how to go
around or how to solve and that's the
situation we're in my reaction to that
is twofold one of them is to try to
bring people we evolved into this
unfortunate sociological situation in
which there are communities around some
of these approaches and to borrow again
a metaphor from Eric they sit on top of
hills in the landscape of theories and
throw rocks to each other and as eric
says we need two things we need people
to get off the hill
and come down into valleys and party and
talk and become friendly and learn to
say not know but but yes and yes your
idea goes this far but maybe if we put
it together with my idea we can go
further yes
so in that spirit of talked several
times with Sean Carroll who's also
written an excellent book recently and
he kind of he plays around as a big fan
of the many-worlds interpretation of
quantum mechanics so I'm a troublemaker
so let me ask well what's your sense of
Sean and the idea of many worlds
interpretation I've read many the
commentary back and forth you guys you
guys are friendly respect each other but
have a lot of fun debating I love Sean
and he know I really he's not he's
articulate and he's a great
representative or an ambassador of
science to the public in four different
fields of science to each other he also
like I do takes philosophy seriously and
unlike what I do in all cases he has
really done the homework he's read a lot
he knows the people he talks to them he
exposes his arguments to the to them and
I did this mysterious thing that we so
often end up on the opposite sides of
with these issues it's fun though it's
fun and I'd love to have a conversation
about that but I would want to include
him
I see about many worlds well no I can
tell you what I think about many I'd
love to but actually on that let me
pause Sean as a podcast you should
definitely figure out how to talk to
Sean I would I actually told Sean I
would love to hear you guys just going
back and forth so I hope you can make
that happen eventually you and sure I
want I won't tell you what it is but
there's something that Sean said to me
in June of 2016
that changed my whole approach to a
problem but I'll have to tell him first
yes and that that they'll be great to
tell him on his podcast so I can't
invite myself to his podcast yeah okay
we'll make it happen
so how many worlds anyway um what's your
view many worlds we talk about
nonlocality many worlds is also a very
uncomfortable idea or beautiful
depending on your perspective it's it's
very nice in terms of I mean there's a
realist aspect to it I think you call
the magical realist
it's just a beautiful line but at the
same time it's very difficult to far
limit human minds to comprehend so what
are your thoughts about it let me start
with the easy and obvious and then go to
the scientific okay it doesn't appeal to
me it doesn't answer the questions that
I want answered and it does so to such a
strong case that went abroad among about
anger and I began looking for principles
and I want to come back and talk about
the use of principles in science because
that's the other thing I was gonna say
and I don't want to lose that
when we started looking for principles
we made our first principle there is
just one world that happens once but so
it's it's not helpful to my personal
approach to my personal agenda but of
course I'm part of a community and my
sense of the many-worlds interpretation
I have thought a lot about it and
struggled a lot with it is the following
first of all this average himself is
what's in Everett and there are several
issues they're connected with the
derivation of the born rule which is the
rule that gives probabilities to events
and the reasons why there is a problem
with probability is that I mentioned the
two ways that physical systems can
evolve the many-worlds interpretation
cuts off one the one having to do with
measurement and just has the other one
the Schrodinger evolution was just a
smooth evolution of the quantum state
but the notion of probability is only in
the second rule which we've thrown away
so where is probably come from and you
have to answer the question because
experimentalist use probabilities to
check the theory now at first sight you
get very confused because there seems to
be a real problem because in the
many-worlds interpretation this talk
about branches is not quite precise but
I'll use it there is a branch in which
everything that might happen does happen
with probability 1 in that branch you
might think you could count the number
of branches in which things do and don't
happen and get numbers that you can
define as something like frequentist
probabilities and Everett did have an
argument in that direction
but the argument gets very subtle when
there are an infinite number of
abilities as is the case in most quantum
systems and my understanding although
I'm not as much of an expert as some
other people is that ever its own
proposal its failed did not work there
then it doesn't stop there there is an
important idea that Everett didn't know
about which is decoherence and it is a
phenomenon that might be very much
relevant and so a number of people post
Everett have tried to make versions of
what you might call many worlds quantum
mechanics and this is a big area and
it's subtle and it's not the kind of
thing that I do well so I consulted
that's why there's two chapters on this
in the book I wrote chapter 10 which is
about Everett's version in Chapter 11
there is a very good group of
philosophers of physics in Oxford
Simon Saunders David Wallace Harvey
Brown and a number of others and of
course this David Deutsch who is there
and those people have developed and put
a lot of work into a very sophisticated
set of ideas designed to come back and
answer that question they have the
flavor of there are really no
probabilities we admit that but imagine
if you if the Everett story was true and
you were living in that multiverse how
would you make bets and so they they use
decision theory from the theory of
probability in gambling and so forth to
shape a story of how you would bet if
you were inside Everett in the universe
and you knew that and there is a debate
among those experts as to whether they
or somebody else has really succeeded
and when I checked in as I was finishing
the book with some of those people like
Simon who's a good friend of mine and
David Wallace they told me
that they weren't sure that any of them
was yet correct so that's why I put in
my book now to add to that sean has his
own approach to that problem in what's
called self referencing or self locating
observers and it doesn't
I just tried to read it and it didn't
make sense to me but I didn't study it
hard I didn't communicate with Sean I
didn't do the things that I would do so
I had nothing to say about in the book
in I don't I don't know whether it's
right or not
you