Kind: captions
Language: en
the following is a conversation with ian
hutchinson a nuclear engineer
and plasma physicist at mit he has made
a number of important contributions in
plasma physics including the magnetic
confinement of plasmas
seeking to enable fusion reactions which
happens to be the
energy source of the stars to be used
for practical energy production
current nuclear reactors by the way are
based on fission as we discuss
ian has also written on the philosophy
of science and the relationship between
science
and religion arguing in particular
against scientism
which is a negative description of the
overreach of the scientific method
to questions not amenable to it on this
latter topic i recommend two of his
books
his new one can a scientist believe in
miracles where he answers more than 200
questions on all aspects of god and
science
and his earlier book on scientism called
monopolizing
knowledge as you may have seen already
i work hard on having an open mind
always questioning my assumptions and in
general marvel at the immense mystery of
everything around us
and the limitations of at least my
mind i'm not religious myself in that i
don't go to the synagogue a church or
mosque
but i see the beautiful bond in the
community that religion at its best can
create
i also see both in scientists and
religious leaders signs of arrogance
hypocrisy
greed and a will to power
we're human whether buddhist christian
hindu jewish muslim
agnostic or atheist this podcast is my
humble attempt to explore a complicated
human nature
what stanislav in his book solaris
called
our own labyrinth of dark passages and
secret chambers
i ask that you try to keep an open mind
as well
and be patient with the limitations of
mine
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here's my conversation with ian
hutchinson
maybe it'd be nice to draw a distinction
between nuclear physics
and plasma physics what is the
distinction
nuclear physics is about the physics of
the nucleus and
my department department of nuclear
science and engineering at mit
is very concerned about all the
interactions and
reactions and and consequences of things
that go on in the nucleus including
nuclear energy
fission energy which is the nuclear
energy that we have already
and fusion energy which is the energy
source of the sun and stars
which we don't quite know how to turn
into practical energy
uh for humankind at the moment
that's what my research has mostly been
aimed at
but plasmas are essentially
the fourth state of matter so if you
think about
solid liquid gas plasma is the fourth
of those states of matter and it's
actually the state of matter which one
reaches
if one raises the temperature so
cold things you know like ice are solid
um liquids are hotter water
and if you heat water beyond 100 degrees
celsius it becomes gas
uh well that's true of most substances
and um plasma is a is a state of matter
in which the electrons are
unbound from the nuclei so they become
separated from the nuclei and can move
separately
so we have positively charged nuclei
and we have negatively charged electrons
then the net is
is still neutral electrically neutral
but a plasma conducts electricity
has all sorts of important properties
that are associated
with that separation and that's what
plasmas are all about
and the reason why my department is
interested in plasma physics very
strongly is because
most things well for one thing most
things in the universe are plasma
the vast majority of matter in the
universe is plasma but but most
particularly
stars and the sun are plasmas
because they're very hot and it's only
in very hot states
that nuclear fusion reactions take place
and we want to understand how to
implement those kind of phenomena
on earth maybe another distinction we
want to
try to get at is a difference between
fission and fusion
as you mentioned fusion is the kind of
reaction happening in the sun so what's
vision and what's fusion
well fission is taking heavy elements
like uranium and breaking them up
and it turns out that that process of
breaking up heavy elements releases
energy
what does it mean to be a heavy helmet
it means that there are many
nuclear particles in the nucleus itself
neutrons and protons um in the
in the nucleus itself so that in the
case of
um uranium there are 92
protons in each nucleus and even more
neutrons so that
the total number of nucleons
in the nucleus nucleons is short for for
either a proton or a neutron
the total number you know might be 235
that's
u235 or it might be 238
that's u238 so those are heavy elements
light elements by contrast have very few
nucleons protons or neutrons in the
nucleus
hydrogen is the lightest nucleus it has
one proton there are actually slightly
heavier forms
of hydrogen isotopes deuterium has
a proton and a neutron and tritium
has a proton and two neutrons so it has
total of three
nucleons in the new in the nucleus
well taking light elements
like isotopes of hydrogen and not
breaking them up but actually
fusing them together reacting them
together to produce heavier elements
typically helium okay which is helium is
a nucleus which has
has two protons and two neutrons
that also releases energy and that and
that or reactions like that
making heavier elements from lighter
elements
is what mostly powers the sun and stars
both fusion and fission release
approximately a million times more
energy per unit mass than chemical
reactions
so a chemical reaction means take
hydrogen take
oxygen react them together let's say and
get
water that releases energy the energy
released in a chemical reaction like
that or the burning of coal or
on oil or whatever else is about a
million times less
per unit mass than what is released in
nuclear reactions
so but it's hard to do it requires
very high energy of impact
and actually it's very easy to
understand why and that is that
those two nuclei if they're both let's
say
hydrogen nuclei one is let's say
deuterium and the other is let's say
tritium
they're both electrically charged and so
the and they're positively charged so
they they
like charges repel everyone knows that
right
so basically to get them close enough
together to react
you have to overcome the repulsion the
electric repulsion
of the two um nuclei from one another
and you have to get them extremely close
to one another in order for the nuclear
forces to overtake
the electrical forces and and actually
form a new nucleus
and so one requires very high energies
of
impact in order for reactions to take
place and those high energies of impact
correspond to very high temperatures
of random motion so that's why you can
do something like that
in the sun so we can build the sun
that's one way to do it
but uh on earth how do you create a
fusion
[Laughter]
reaction yeah well nature engineering
nature's fusion uh reactors are indeed
the stars
and uh they are very hot in the set in
the center
and re and they reach the point where
they
release more energy from those reactions
than they lose by radiation and
transport to the surface
and so forth and that's a state of
ignition
and and that's what we have to achieve
to
to give net energy it's like lighting a
fire
if you if you have a if you have a
bundle of sticks and you hold a match up
to it
and you see smoke coming from the sticks
but you take the match away and the
and the and the sticks just fizzle out
that's not
the reason they did it fizzled out is
that yes they were burning
there was smoke coming from them but
they were not ignited
but if you are able to take the match
away and they keep burning and they are
generating enough heat
to keep themselves hot and hence keep
the reactions going
that's chemical ignition well what we
need to do
what the stars do in order to generate
nuclear fusion energy is
they are ignited they are generated
enough energy to keep themselves hot
and that's what we've got to do on earth
if we're going to make
fusion work on earth but it's much
harder to do
on earth than it is you know in a star
because you know we need temperatures
of order tens of millions of
degrees celsius in order for the
reactions to go
fast enough to generate enough
electricity to keep it
or enough energy to keep it going and
and so um if you've got something that's
tens of millions of degrees
celsius and you want to keep it all
together and keep the heat in long
enough
to have enough reactions taking place
you can't just put it in a bottle
you know plastic or glass it would be
gone you know it's
in milliseconds um so
um you have to have some non-material
mechanism of confining the plasma
in the case of stars that non-material
force
is gravity so gravity is what holds a
star together it's what
holds the plasma in long enough for it
to react
and and and sustain itself by
the the fusion reactions but on earth
gravity is extremely weak i mean i don't
mean to say we don't fall yes we fall
but the the mutual gravitational
attraction
of small objects is very weak compared
with the electrical repulsion or any
other force that you can think about
on earth and so we need a stronger force
to keep the plasma together to confine
it
and the predominant attempt
at making fusion work on earth is to use
magnetic fields
to confine the plasma and that's what
i've worked on for much
essentially most of my career is to
understand
how we can and how best we can confine
these incredibly hot gases plasmas using
magnetic fields with the ultimate
objective
of releasing fusion energy on earth and
you know generating electricity with it
and powering our society with it
a dumb question so on top of the
magnetic fields
do you also need the plastic water
bottle walls or is it purely magnetic
fields
well actually what we do need walls
um those walls must be kept away from
the plasma because otherwise they'd be
melted or the plasma must be kept away
from them inside
inside of them but the main purpose of
the walls
is not to keep the plasma in it's to
keep the atmosphere out
so if we want to do it on earth where
there's air
we want the plasma to consist of
hydrogen isotopes or other things the
things we're trying to react
and by the way the density
of those plasmas at least in magnetic
confinement fusion
is very low it's maybe a million times
less
than the density of air in this room
so in order for a fusion reactor like
that to work
you have to keep all of the air out and
just keep the plasma in so yes there are
other things
but those are things that are relatively
easy i mean making a vacuum
these days is technologically quite
quite straightforward we know how to do
that
okay what we don't quite know how to do
is to make
a confinement uh device that
isolates the plasma well enough so that
it
so that it's able to keep itself burning
with its own reaction
so maybe can you talk about what a
takamaka is
the russian acronym from which the word
tokamak is built just means toroidal
magnetic chamber
so it's a toroidal chamber taurus is
is a geometric shape which is like a
doughnut with a hole down the middle
okay and so it's the so it's the meat of
the doughnut
okay that's the taurus um and it's
and it's got a magnetic field so that's
really all takamak
uh means but the particular
configuration
um that we're the that is very
widespread and there's the sort of
best prospect in the least in the near
term for making fusion energy work
is one in which there's a very strong
magnetic field
the the long way around the
doughnut around the torus um so you've
got to imagine that there's this
doughnut shape with an embedded magnetic
field just going round and round
the long way the the big advantage of
that
is that plasma particles
are when they're in a in the presence of
a magnetic field
feel strong forces from the magnetic
field and those forces
make the particles gyrate around the
direction
of the magnetic field line so basically
the particles follow helical orbits like
like a following like a spring that's
directed along the magnetic field
well if you make the magnetic field go
in inside this toroidal chamber and just
simply go round and round the chamber
then because of this helical orbit
the particles can't move fast across the
magnetic field
but they can move very quickly along the
magnetic field
and if you have a magnetic field that
doesn't leave the chamber
it doesn't matter if they move along the
magnetic field it does
it means it doesn't mean they're going
to exit the chamber
but if you just had a straight magnetic
field as you you know for example
coming from um you know a bar a
helmholtz coil or
or a bar magnet then you'd have to have
ends it would come would come to the end
ends of the chamber somewhere in the and
the particles would hit the ends and
and they would lose their energy so
that's why it's toroidal
and that's why we have a strong magnetic
field it's
providing a confinement against motion
in the in the direction that would lead
the particles to leave the chamber
it turns out that then here we're
getting a little bit technical but it
turns out that
a toroidal field alone is not enough and
so you need more
fields to produce true true confinement
of
plasma and we get those by passing a
current as well
through the plasma itself i can make
sure it stays on track
well that what that does is makes the
field lines themselves
into much bigger helices and
that for reasons that are too
complicated to explain
that clinches the confinement of the
particles
at least in terms of their single
particle orbits so they don't leave the
chamber
and so when the particles are flying
along this uh
this this doughnut the inside of the
donut
uh are they what's where's the
generation of the energy coming from are
they smashing
into each other yeah eventually i mean
in a fusion reactor
there will be deuterons and triti and
tritons and they will be
smashing in they will be very hot
they'll be 100 million degrees
celsius or something so they're moving
thermally with very large thermal
energies
in random directions and they will
collide with one another
and have fusion reactions when those
fusion reactions take place
energy is released large amounts of
energy is released in the form of
particles
one of the particles that's released is
an alpha particle which is also charged
and it's also confined
and that alpha particle stays in the in
the in the doughnut and heats the other
particles that are in that doughnut
so it transfers its energy to those and
they it keeps them hot
there's there's some leaking of heat all
the time a little bit of radiation
some transport and so forth there's also
a neutron released from that reaction
the neutron carries out four-fifths of
the fusion energy
and that will have to be captured in a
blanket that surrounds
the chamber in which we
take the energy drive
some kind of electrical
generator from you know thermal thermal
engine
um gas turbine or something like that
and power the power you got energy
so where do we stand where do we stand
on
getting this thing to be uh something
that actually works it generates energy
yep
well um there have been experiments that
have generated
net nuclear energies or nuclear powers
in the vicinity of
um you know a few tens of megawatts
for a few seconds so that's
you know 10 megajoules that's not much
energy
it's a few doughnuts worth of energy
okay yeah literal donut
that's right um
but um but we have studied how well
tokamax can confine plasmas and so we
now
understand in in rather great detail
um the way they work and we're able to
predict what is
going to be required in order to build a
tokamak that becomes self-sustaining
that that becomes essentially ignited
or very so close to ignited that it
doesn't matter
and and at the moment at least if you
use the modest magnetic field
values still very strong but but limited
limited magnetic field values
you have to build a very big device and
so we are at the moment
worldwide fusion research is
at the moment in the process of building
a very big experiment
that's located in the south of france
it's called eta
i-t-e-r which means the way or
just means the international tokamak
experimental reactor if you like
um and that experiment is designed to
reach this burning plasma state
and to generate about 500
megawatts of fusion power
for hundreds of seconds at a time it'll
still only be
an experiment it won't put electricity
on the grid or anything like that
it's it's to figure out what whether it
works and and with what the remaining
engineering challenges are it's a
scientific experiment
it won't be engineered to run round the
clock and
and so on and so forth which ultimately
one one needs to do
in order to make something that's
practical for generating electricity
but it will be the first demonstration
on earth
of a controlled fusion reaction reaction
for you know long time time periods is
that exciting to you
uh it it it's been an objective that is
in many ways motivated my entire career
and the career career of many people
like me in the field
um i have to admit though
that one of the problems with eta is
that it's an extremely big and expensive
and
long time to build experiment and so it
won't even come into operation
until about 2025 even though it's been
being built for
10 years and it's been it was designed
for 30 years before that
right and so that's actually one of the
big disappointments of my career
in a certain sense which is that we
won't get to
a burning fusion reaction until well
past the first
operation of eater and whether i'm alive
or not i don't know
but i certainly will be well and truly
retired by the time that happens
and so when i realized maybe some years
ago that that was going to be the case
it was a discouragement to me let's put
it like that
but if we can try to look maybe
in a ridiculous kind of way look into uh
100 years from now 200 years 500 years
from now
and we you know there's folks like elon
musk uh trying to uh travel outside the
solar system
i mean the amount of energy we need for
some of the exciting things we want to
do
in this world if we look again 100 years
from now
uh seems to be a very large amount
so do you think fusion energy will
eventually
uh sometime into your retirement uh
will be basically uh behind
most of the things we do look i
absolutely
think that fusion research is
completely justified in fact we should
be spending more time and effort on it
than we currently do
but it isn't going to be a magic bullet
that somehow
solves all the problems of energy by the
way that's a generic statement you can
make about
any energy source in my view i think
it's a grave mistake to think that
science
of any sort is suddenly going to find a
magic bullet for meeting all the energy
needs of society or any of the other
needs of society by the way
but and we can talk about that hopefully
later
but but but but fusion is very
worthwhile and we should be doing it
um and and so my disappointment
that i just expressed was in a certain
sense of personal disappointment
i do think that fusion energy is a
terrific challenge it's very difficult
to bring
the energy source of the sun and stars
down to earth
this does contrast in a certain sense
with fission energy by contrast fission
energy
efficient to build a fission reactor
proved to be amazingly easy
you know we did it um within a few years
of discovering nuclear fission people
had
figured out how to build a reactor and
did so
um you know during the second world war
which is by the way
fission is how the current nuclear power
plants work yeah
and so we have uh nuclear energy today
because fission uh reactors are
relatively easy to build you've got to
have what's hard is getting
the materials okay and that's just as
well because if everyone could get those
materials you know there would be
weapons proliferation and so forth
but it wasn't um all that long um
after even the discovery of nuclear
fission
that fission reactors were built and
fission reactors of course operated
before we had weapons
um so um
i think nuclear power is
obviously important to
meet the energy challenges of our
age it is completely intrinsically
completely
uh co2 emissions free
and in fact the wastes that come from
nuclear power whether it's fission or
fusion for that matter
are so moderate in quantity
that that we shouldn't really be worried
about them
um i mean yes fission products are
highly radioactive and
and we need to keep them away from
people but there's so little of them
it's that keeping them away from people
is not particularly difficult
and so while people complain a lot about
the
the drawbacks of fish and energy um
i think most of those complaints are
ill-informed
um we can talk about you know the the
challenges and the disasters if you like
of
uh off of fission reactors but i think
fission in the near term offers a
terrific opportunity
for environmentally friendly energy
which in which in the world as a whole
is rapidly being
taken advantage of you know china and
india and places like that
are rapidly building fission plants
we're not rapidly building fission
plants
in the u.s although we are actually
building two at the moment
um two new ones um but we do still
get 20 of our electricity from fish and
energy and we could get a lot more
so it's clean energy so it's clean
energy now
now again the concern is there's a very
popular
hbo show and just came out on chernobyl
uh there's the three mile island there's
fukushima that's the most recent
disaster
so there's a kind of a concern of um
yeah i mean nuclear disasters
is that what do you make of that kind of
uh concern especially if we look into
the future of fission energy based uh
reactors
well first of all let me say one or two
words about the contrast between fission
and fusion and then we'll come on to the
question of the
disasters and so forth fission does have
some drawbacks and they're
and they're largely to do with four
four main areas one is do we have enough
uranium or other
fissile fuels to to supply our energy
needs
for a long time the answer to that is
that we know we have
um enough uranium to support fission
energy
worldwide for thousands of years
but maybe not for millions of years okay
so that's resources um secondly
there there are issues to do with wastes
fission wastes
are highly radioactive and some of them
are volatile
and so for example um in
fukushima the the problem was
that some fraction of the fish and waste
were volatilized
and went out as a cloud and and polluted
air areas with um cesium
137 strontium 90 and things like that
so that's a challenge of fission um
there's a problem of
safety uh beyond that and that is
that um in fission it's hard to turn the
reactor off
when you turn when you stop the nuclear
reactions
there is still a lot of heat being
liberated from the fission products
and that is actually what the problem
was at fukushima
the fukushima reactors were shut down
the moment that the earthquake took
place
and they were shut down safely what then
happened
after that fukushima was you know there
were there was this enormous
tidal wave um many tens of meters high
that came through
and destroyed the electricity
grid feed to the fukushima reactors and
their
cooling was then turned off and it was
the after heat
of the turned off reactors that
eventually caused the problems that
led to release and so that so that is
that's a safety concern and then and
then
finally there's a problem of
proliferation
and that is that fission reactors need
fissile fuel
and the technologies for producing the
under
enriching and so forth the fuels can be
used can be
can be um by by bad actors
to generate um the materials needed for
a nuclear weapon and that's
a very very serious concern so those are
the four problems
fusion has major advantages in respect
of
all of those problems it has more uh
longer term um fuel resources
it has far more benign waste
issues the react the radioactivity from
fusion reactions is at least a hundred
times less than it is from fission
reactions
it has um no none essentially none of
this
after heat problem because it doesn't
produce fission products that are
highly radioactive and generating their
own heat
when it's turned off in fact the hard
part of fusion is turning it on not
turning it off
and and finally you don't need the same
uh
fission technology to do to make uh
fusion work and so it
there it's got terrific advantages from
the point of view of proliferation
control
so those are the those are four main
issues which make fusion seem attractive
technologically
um because they address some of the
problems of fission energy
i don't mean to say that fission energy
is overwhelmingly problematic
but clearly there have been catastrophes
associated with fission reactors
fukushima actually is i think in many
ways
often overstated as a disaster because
after all
nobody was killed by the reactors
essentially
zero and that's in the context
of a disaster a tsunami
that killed between 15 and 20 000
people instantaneous more or less
instantaneously
so you know in the scale of risks
um one should take the view that uh
in my in my in my estimation that um
fission energy came out of that looking
pretty good okay
of course that's not the popular
conception okay
yes that's gonna i mean with a lot of
things that threaten our well-being
we seem to be very uh bad
uh users of data we seem to be very
scared of
uh shark attacks and not at all scared
of
car accidents and this kind of
miscalculation and
i think from everything and i understand
uh
nuclear energy efficient based energy
goes into that category
it's one of the safest one of the
cleanest forms of energy
and yet the pr uh
whoever does the pr for nuclear energy
is not uh
has a hard job ahead of them at the
moment well i think part of that is
their association with nuclear weapons
right because when you say the word
nuclear people don't instantly think
about nuclear energy they think about
nuclear weapons
and and so there is you know perhaps
um a natural tendency to do that but yes
i agree with you people are very
poor at estimating risks and they react
emotionally not rationally in most of
these situations
can we talk about nuclear weapons just
for a little bit
so fission is the kind of reaction
that's central to the nuclear weapons we
have today
that's what sets them off that's what
sets them off
so if we look at the hydrogen bomb maybe
you can say how these different
weapons work so the earliest nuclear
weapons the
the nuclear bombs that were dropped on
japan etc etc
were pure fission weapons they used
uh enriched uranium or plutonium
and their energy is essentially entirely
derived
from fission reactions but
it was early realized that more energy
was available
if one could somehow combine a fission
bomb
with um fusion reactions
um because the fusion reactions
give more energy per unit mass than
than fission reactions and these were
this was called
the super you might have heard of the
expression the super or more simply
hydrogen bombs okay um
bombs which use isotopes of hydrogen and
the fusion reactions associated with
them
like you said it's hard to turn on it's
hard to turn on because you need very
high temperatures
and you need confinement of that
long enough for the reactions to take
place and so a bomb
actually a thermonuclear bomb
or a hydrogen bomb
has essentially
a chemical implosion
which then sets off a fission
explosion which then sets off
and compresses hydrogen isotopes
and other things which i don't know
because i don't i've never had a
security clearance okay so i so i can't
betray any
secrets about weapons because i've never
been a party to them but
because i know a lot about this problem
i
can guess okay um and sets off
fusion reactions in the middle okay so
that's basically
it's that sequence of things which
produce these enormous
you know multi-megaton uh bombs that
have very large yields um
and so fusion alone can't get can't get
you there
it is actually possible to set off or to
try to set off
little fusion bombs alone without the
surrounding fission explosion
and that is what is called laser fusion
so another approach to fusion which
actually is
mostly researched in the
weapons complex the national labs and so
forth
because it's more associated with the
technology of of weapons
is inertial fusion so if if you decide
instead of
trying to make your plasma just sit
there in this taurus in the in the
tokamak and
be controlled steady state with a
magnetic field if you if you're willing
to accept that
i'll just set off an explosion okay and
then i'll gather the energy from that
somehow i don't quite know how but let's
not ask that question too much
um then it is possible
to imagine generating fusion alone
explosions and and the way you do it is
you take
some small amount of deuterium tritium
fuel
you bombard it with energy from all
sides
and this is what the lasers are used for
extremely powerful at lasers
which compresses the pe the pelleted
fusion
and heats it it compresses it to such a
high
density and temperature that the
reactions take place very very quickly
and in fact they can take place so
quickly that they're
it's all over with before the thing
flies apart
wow and that is heated up really fast
that is inertial
fusion okay is that useful for
energy generation not yet
i mean there are those people who think
it will be but you may have heard of the
big experiment called the national
ignition facility which was built at
livermore starting
in the late 1990s and has been in
operation since
around about 2010. it was designed
in with the claim that it would reach
ignition fusion ignition
in this pulsed form where the reactions
have got over with
so quickly before the thing whole thing
flies apart it didn't actually reach
ignition and i
doesn't look as if it will although you
know we never know maybe people figure
out how to make it work better
but the answer is in principle it seems
possible
to reach ignition in this way maybe not
with that particular laser facility
are you surprised that uh
we humans haven't destroyed ourselves
given
that we've invented such powerful tools
of destruction
like what do you make of the the fact
that for many decades
we've had nuclear weapons now speaking
about estimating risk
at least to me it's exceptionally
surprising i was born in the soviet
union
that um that big egos
of the big leaders when rubbing up
against each other have not created uh
the kind of destruction
one was everybody was afraid of for
decades
well i must say i'm extremely thankful
that it hasn't i don't know whether i'm
surprised about it
i've never thought about it from the
point of view of
is it surprising that we've we've
avoided it i'm just very thankful that
we have i think that there
is a sense in which cooler heads have
prevailed at
crucial moments i think there is also
a sense in which you know mutually
assured destruction
um has in fact worked as
a policy to restrain the great powers
from going to war and in fact you know
the
the the fact that we haven't had
a world war you know since the 1940s
is perhaps even attributable to
nuclear weapons in a kind of strange and
peculiar way but i think humans
are deeply uh flawed
and sinful people and i certainly don't
feel gap that we're guaranteed that it's
going to go on like this
and we'll talk about the sort of the
biggest picture view of it all
uh but let me just ask in terms of your
worries
of if we look 100 years from now we're
in the middle of
what is now a natural pandemic that from
the looks of it
it fortunately is not as bad as it could
have possibly been if you look at the
spanish flu if you look at the history
of pandemics
if you look at all the possible
pandemics that could have been that that
folks like bill gates are exceptionally
terrified about we've
uh i know many people are suffering
uh but it's it's it's better than it
could have been uh so
and now we're talking about nuclear
weapons in terms of existential threats
to us
as sinful humans uh what worries you the
most
is it nuclear weapons is is it
natural pandemics engineered pandemics
nanotechnology in my field of artificial
intelligence some people
are afraid of uh killer robots and
robots yeah
is there do you think in those
existential terms uh
and and do any aspect do any of those
things worry you
i am certainly not confident that
my children and grandchildren will
experience the benefits of civilization
that i have enjoyed i think it's
possible for our civilizations to break
down
catastrophically i also
think that it's possible for our
civilizations to break down
progressively and i think they will
if we continue to have the explosion of
population on the planet that we
currently have
i mean it's quite it's quite
wrong to think of our problems as mostly
being co2
if we can just solve co2 then we can go
on
having this you know continually
expanding economy
everywhere in the world of course you
can't do that okay
i mean there is a finite you know
bearing capacity of our planet
on the resources of our planet on the
resources of our planet
and and we can't continue to do that so
i think there are lots of technical
reasons
why um a continually expanding
economy and and uh and civilization
is impossible and therefore um
actually i'm as much nervous about the
fact that our
population is eight billion or something
uh right now
worldwide as i am about um the fact that
you know a few million people would be
would be killed by
covet 19. i mean i don't want to be
callous about this but from the big
picture it seems like
that's much more of a problem
overpopulation
people not dying is ultimately more of a
problem
uh than people dying um so you know that
probably sounds incredibly callousy or
to listeners but i think it's simply you
know a sober assessment of the situation
is there is there ways from
the way those eight billion or seven
billion or whatever the number is
live that could make it sustainable
uh you know because you've kind of
implied there's a kind of uh
we have especially in the west this kind
of capitalist view of uh
really consuming a lot of resources is
there a way to
like if you could change uh one thing or
a few things what would you
change to make this life make it look
more likely that your grandchildren have
a better life than you well okay so
let's talk a bit about energy because
that's something i know a lot a lot
about having thought about it most of my
career
in order to reach a steady-state co2
level
okay that's acceptable in terms of
global climate change and so on and so
forth
we need to reduce our
carbon emissions by at least a factor of
10 worldwide
okay what's more
you know um the average
energy consumption and hence co2
emission of people in the world
is less than a tenth of what we
per capita of than what we have
in the west in america and europe and so
forth
so if you have in mind some utopia in
the future where we can where we've
reached a sustainable
use of energy and we've also reached
a situation in which there's far
less inequity in the world in the sense
that people have
share the energy resources more
uniformly
then what what that is equivalent to
would be to reduce
the co2 emissions in
western economies not by a factor of 10
but by a factor of 100 in other words
has to go down to one percent of what it
is now
okay yeah so you know when people talk
about
uh you know let's use natural gas
because you know maybe it
only uses 60 of the energy of coal
it's complete nonsense we that's not not
even scratching the surface of what we
would need to do so you know is that
going to be feasible
i i i very much doubt it
and therefore i actually doubt that we
can reach
um a level of energy
of fossil energy use that is one percent
of the current use in the west without
totally dramatic changes either in
you know our society our use of of
energy and so forth which actually
of course is much of that energy is used
for producing food and so on and so
forth so it's actually
not so obvious that we can we can get we
can cut down our energy usage by that
factor
or we've got to reduce the human
population population
so you run up against that number that's
increasing still
and you don't think that could be it's
depressing no it's not uh
it's not it's not it's not depressing
it's um
it's difficult like many truths are uh
do you do you have a hope uh that there
could be a technological solution
in short no there is no technological
solution
to for example for population control i
mean we have the technology
just you know to prevent ourselves
bearing children that's not a problem
technology's in okay solved
the challenge is society the challenges
human choices the challenges almost
entirely
human and sociological not technology
not technology and when people thought
talk about energy they
they think that there's some kind of
technological magic bullet for this but
there isn't
okay and and there isn't for the reasons
i just mentioned
not because it's obvious there isn't but
actually there isn't
uh and and in in any case um
that it's true of energy it's true of
pollution it's true of human population
it's true of
most of the big challenges in our
society
are not scientific or technological
challenges
they're human sociological challenges
and that's why i think it's a terrible
mistake
um even for folks like me who work at
you know
well the high temple of science and
technology
in in america and maybe in the galaxy
yeah i mean
you know it's it's it's mit it's mit
best university in the world
it's it's a terrible mistake if we give
the impression
that technology is going to solve it all
technology will make
tremendous contributions and i think
it's it's worth working on it
but it's a disaster if you think it's
going to solve all of our problems and
and actually um you know i've written a
whole book about
the question of of scientism and the and
the over
emphasis on science both as a way of of
solving problems
through technology but also as a way of
gaining knowledge i think it's not
all of the knowledge there is either
yeah i think that book
and uh your journey there is fascinating
so maybe you can go there can
can you tell me about your on a personal
side your
the personal journey of your faith of
christianity and your relationship with
uh
with god with religion in general
yeah in my in my latest book uh can a
scientist believe in miracles i
i i give a first i devote most of the
first chapter to telling how
how i became a christian um why i became
a christian i
i didn't grow up as a christian which is
fascinating i mean you didn't grow up as
a christian so you
you've discovered the beauty of uh god
and physics at the same time
that's a very poetic way of putting it
but yes i would accept that
um i became a christian when i was an
undergraduate at cambridge university
um i i had you know i had gone to a
school in which there was religion
kind of was part of the society there
were prayers and
at the at the at the daily you know
gathering of the
of the students uh the assembly of the
students um but i
but i didn't really believe it i just
sort of went along with it and it wasn't
particularly
you know aggressive or benign you know
blind it just sort of was there
um but i didn't believe it um i didn't
didn't make much sense to me but when i
but i came across christians from time
to time and when i went to cambridge
university
um two of my closest friends who
turned out were christians and i think
it was that
was the most important influence on me
um
that that here were uh
two people who were really smart like me
i i'm giving you my yeah my impression
at the time the way i the way i felt at
the time um
and and they thought christianity made
sense and and you know
testified to its significance in their
lives and
so that was a very important influence
on me
and i and ultimately i mean the reason i
i i hadn't i hadn't i didn't see
christianity as some kind of great evil
the way it's sometimes portrayed by the
by the radical atheists of this century
i mean i think that's nonsense but
but but i so i think there were certain
attractive things if you go to a
university like cambridge you know
you're surrounded by
by by western culture you know from from
about
you know the 15th century onwards and
that saturated
with christian art and architecture
and so forth and so it's hard it's hard
not to recognize
that christianity is in fact the
foundation of western society in western
culture
well western civilization um
so so i i mean maybe i was in that sense
favorably
disposed towards christianity as a
religion but as a personal faith it
didn't mean anything to me but i became
convinced really of two things one is
that
the evidence for the resurrection of
jesus christ is actually rather good
i mean it's not a proof it's not kind of
some some kind of scientific demonstrate
or mathematical demonstration
but it's actually extremely good it's
not scientific evidence by and large
it's historical evidence historical
evidence yeah
um so that was one thing and the other
thing that
came to me when i was at cambridge it
became clear
that christianity ultimately is not
you know some kind of moral
theory or philosophy or something like
that
it is or elite or at least it claims to
be um
a personal relationship with god which
is made possible
you know by um what jesus did and on the
cross and
and his life and his teaching and and
it's a personal call
to a relationship with god and
that had i'd never thought of it in
those terms when i was you know
when i was younger and that that that
thought became
um attractive to me i mean i i think
most people find the person of christ
and his teachings you know compelling
insert
in a certain sense what do you mean by
personal do you mean personal
for you like a relationship like it's a
meditative
like you specifically you even have
a connection uh with god uh
and and then the other side you say
personal um
with the actual body the person of jesus
christ
so all of those things what do you mean
by personal connection and why that was
me well so as well for the stupid
question
no that's okay no problem as a christian
i believe that i have a relationship
with god
which is best expressed by saying that
it's personal
and that comes about because you know
jesus through his acts has
reconciled me with god me a sinner
me someone full of of of
of sins of of failings of ways in which
i don't live up to even my own ideals
let alone the ideals of a holy god
have been reconciled to the creator of
everything
um and and so christians
myself included believe that prayer is
in a certain sense a connection with god
and there are times when i have felt you
know that god
spoke to me i don't mean necessarily
orally in words but
showed me things or enlightened me or
inspired me
in ways um that um
i i attribute to him so i see it as a
as a two-way you know relationship in a
certain sense of course it's a very
asymmetrical relationship but
nevertheless christians think that it's
a two-way
it's a two-way street we're not just
talking into the air when we
say we want i'm going to pray for
someone
in this two-way communication uh
is there a way that you could try to
describe on a podcast
what is god what is god like
uh in your view
if if you try to describe is it a force
um is it a is it uh for you
intellectually is a set of metaphors
that you use to reason
about the world is it um
is it uh is it is it kind of a computer
that does some computation that's the
infinitely powerful computer
uh or is it like santa claus a guy with
a with a beard
on the cloud like uh i don't mean um
i don't mean what god actually is i mean
in your limited
uh cognitive capacity as a human
what do you actually uh what do you find
helpful for thinking of what god
actually looks like what is
god well let me start by saying none of
the above okay
i mean clearly god in the christian god
um uh the god of abraham isaac and jacob
etc
um it is is not any of those things
because all of those things you just
mentioned
are phenomena or or or
entities in the created world and the
most fundamental thing
about monotheism as you know
abraham and moses and so forth handed it
down
is that god is not an entity within
the creation within the universe that
god is the creator of it all
and that's what genesis first two
chapters of genesis is really about
it's it's not it's not about telling us
you know how god created the world it's
about telling
us and telling the early hebrews that
god created
the world okay and that therefore he is
not you know simply an entity within
it on the other hand you know our finite
minds
have a pretty hard time encompassing
that so
so one has to therefore work in terms of
metaphors and images and
and so forth and um
i think we would know very little about
who god is um if we if it was simply uh
if we were simply left to our own
devices
you know if if we were just you know
here you are you're in the universe
try to figure out who who made it and uh
and so forth well you know philosophers
think they can
do a little bit of that maybe uh and
theologians think that they can do a
little bit more
but um but christians think
uh that god has actually helped us along
a lot
by revealing himself and and we say
that he's revealed himself supremely in
the person of jesus christ
um and so you know when jesus says to
his disciples if you've seen me you've
seen the father
then that is in a certain sense a watch
word for answering this question for
christians
it is that supremely if we want to
help ourselves understand who god really
is
we look to jesus we look to what he did
we look to what he
said uh and so forth um
and we believe that he
is one with the father and that's why we
believe you know in the trinity i mean
it's basically because
um that revelation is extremely um
central to christian belief and teaching
so in that in that sense through jesus
there was um that's kind of a historical
moment
that's profound that's really powerful
but do you also
think that god makes himself seen in
less obvious ways
in our world today absolutely
absolutely i mean it's it's certainly
been
the outlook of um
jews and christians throughout history
that god is seen in the creation that we
when we look at the creation
we see to some extent the wonder the
majesty the might of the person or
the entity but the person who created it
and and that's a way in which scientists
particularly
uh have over over the ages and
certainly over most of the last five
centuries since the
scientific revolution scientists have
seen in a certain sense the hand of god
in creation i mean
this leads us perhaps to a different
discussion but i mean
it's it's remarkable to me how
influential
um christianity and religion in
generally has been
in science yeah most of the scientists
through history as if
you described i mean god has been a very
big part of their life
and they were certainly up until the
beginning of the 20th century that was
the case
so maybe this is a good time to can you
tell me what scientism is
yeah i mean the short answer is that's
by scientism
we me we mean the belief that science is
all the real knowledge