Kind: captions
Language: en
[Applause]
what will happen tomorrow is not random
in other words it's at least somewhat
predictable I mean not entirely to be
sure but some things will happen for
certain and other things definitely
won't for example the Sun will rise
water will still freeze at zero degrees
Celsius and you won't become Michael
Stevens we know this because everything
in the universe is made of twelve
fundamental particles and they interact
in four predictable ways what if I were
able to determine the positions and
velocities of every single one of these
particles in the universe well you would
be the intelligence envisioned by
Laplace who thought if you could really
figure out where everything is and how
fast it's moving you would know the
entire future of the universe because
you know how every particle interacts
with every other particle Wow so nothing
would be unpredictable which means
nothing would be random not even human
behavior since we are made of the same
fundamental particles as everything in
the rest of the universe everything we
will ever do or have ever done would be
determined by the information in the
state of the universe at any one time
but what is information well it seems to
be fundamentally about order the order
of molecules in your DNA contained the
information needed to make you it is the
order of zeros and ones streaming
through the internet that contain all
the information required to play this
video it is the order of letters that
makes a word on the order of words that
makes a sentence that carries
information so fundamentally information
seems to be about order regularity that
is until you really think about it I
mean does every letter of a word carry
the same amount of information no I mean
after a cue you know almost for certain
that the next letter will be a u after a
th there will probably be an e so these
letters carry very little information
because you could predict them
beforehand they are redundant in fact
the founder of information theory Claude
Shannon estimated the redundancy of
English at about 75% which is why we can
make sense of things like this
so English can be compressed because it
is not random it has patterns
similarly video is compressible because
of its regularities in each frame the
pixels of similar color cluster together
Plus from frame to frame most of the
pixels don't change so you only need to
record the ones that do change you can
take advantage of this technique to
create some trippy effects known as data
moshing it's the application of the
movement data from one video to the
pixels of another it also means that an
average video can be compressed to just
one thousandth of its original size but
what is the most you can't compress
something well anything that is not
random any patterns or regularities can
be reduced because they are predictable
so you can continue shrinking a file
down until what you're left with is
totally random and that will contain all
of the information of the original item
but distilled pure information so pure
information is randomness if you want to
know how much information something
contains you need to know how random it
is and randomness is disorder what we
also call entropy so information
fundamentally is entropy this makes
sense if you consider a string of binary
digits for example this string is
perfectly ordered it has very low
entropy and it contains no information
that's the state of an erased hard drive
now this string contains slightly more
information but again the regularities
allow it to be easily compressed so the
string that contains the maximum amount
of information is just a random set of
zeros and ones it has maximum entropy
because it's totally disordered you
could not predict any of those digits by
looking at any of the other digits and
if you wanted to send this information
to someone you would have no other
option but to send the whole string of
digits there's no way to compress it but
here's the thing about any object that
contains maximum information
us as human beings they carry no meaning
for example a video containing maximum
information we look like this it is just
white noise the color of each pixel is
independent of all the other pixels and
they all change randomly this video
could not be compressed because it's
already totally random now a random
sequence of DNA would not make an
organism and a random string of letters
does not generally make a word we are
drawn to things that are neither
perfectly ordered containing no
information nor are they perfectly
disordered containing maximum
information somewhere in the middle we
can recognize complex patterns and that
is where we derive meaning in music
poetry and ideas it is this search for
meaning that leads us to propose
scientific theories which if you think
about it are really our way of
compressing the universe for example
general relativity our current theory of
gravity compresses into one short
equation everything from how an Apple
falls to the earth to have a moon orbits
the earth and all the planets orbit the
Sun how the Sun orbits a supermassive
black hole at the centre of our galaxy
how black holes form and behave and how
the whole universe expands out from the
Big Bang now that we have this theory
the future is more predictable I mean we
can predict eclipses thousands of years
into the future so with all of our
scientific theories does that mean that
the universe is completely not random
that it is perfectly predictable well
let's assume for a second that Laplace
was right and that knowing the state of
the universe at any one time means you
also know its state at every other time
as well well that would mean that the
information in our universe would be
constant but if information is entropy
that would mean the entropy of the
universe is also constant and that does
not appear to be the universe that we
live in the second law of thermodynamics
states that entropy in the universe
increases with time or in other words
things don't stir themselves apart but
if entropy is going up that
the information in our universe is
constantly increasing that makes sense
because it would take more information
to specify the state of the universe now
then right after the Big Bang so where
is this new information coming from my
best bet is quantum mechanics quantum
mechanics describes how the twelve
fundamental particles behave and as
spectacularly successful as it is it is
only a probabilistic theory meaning that
you cannot predict with absolute
certainty where an electrons say will be
at some later time you can only
calculate probabilities of where you are
likely to find it so when you do
interact with it and locate the electron
at a particular point you have gained
information you now know something that
you couldn't have predicted with
certainty beforehand this drove Einstein
crazy he said God does not play dice
referring to this I mean he wished that
we could compress our theory of quantum
mechanics further so that we could
really figure out where these particles
were going to be but maybe the reason
why we haven't been able to compress
quantum mechanics further is because
fundamentally it's random fundamentally
new information is being generated every
time a quantum event like that occurs in
that case it could be these quantum
measurements which are driving up the
entropy of the universe they are
creating new information all of the time
and that means the disorder in our
universe must go up this is what we
observe as the second law of
thermodynamics you know we often think
about the second law as a curse as
though everything which is ordered is
going towards disorder but maybe I mean
it's only in a universe where this law
is obeyed that the truly unexpected can
occur that the future can be actually
undetermined for us really to have free
will we need the second law of
thermodynamics now you might think that
these quantum events are too small to
have any meaningful impact on the
evolution of the universe but that is
not true
and that's because there are physical
systems which are so dependent so
sensitive to the initial conditions that
any tiny change will end up making a big
difference later down the track
that's called chaos but it's also known
as the butterfly effect so you and I
could be such physical systems chaotic
systems and our free will could come
from quantum events in our brains so it
looks as though we live in a universe
where the future is yet to be determined
that is to say it's at least somewhat
random but Derek what is the most random
thing possible in the universe you know
it's such a good question I'm talking
about it over on Vsauce you want to go
find out about randomness with me let's
go check it out all right and you can
decide whether to click over or not oh
that's nice
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