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(Circus music)

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[Ted N' Ed's Carnival]

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[John Lloyd's Inventory of the Invisible]

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[Adapted from a TEDTalk
given by John Lloyd in 2009]

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June Cohen: Our next speaker
has spent his whole career

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eliciting that sense of wonder.

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Please welcome John Lloyd.

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(Applause)

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[Hall of Mirrors]

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The question is, "What is invisible?"

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There's more of it
than you think, actually.

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Everything, I would say --
everything that matters --

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Except every thing, and except matter.

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We can see matter

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but we can't see what's the matter.

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We can see the stars and the planets
but we can't see what holds them apart,

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or what draws them together.

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With matter as with people,
we see only the skin of things,

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we can't see into the engine room,
we can't see what makes people tick,

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at least not without difficulty,

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and the closer we look at anything,
the more it disappears.

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In fact, if you look
really closely at stuff,

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if you look at the basic
substructure of matter,

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there isn't anything there.

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Electrons disappear in a kind of fuzz,
and there is only energy.

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One of the interesting things
about invisibility is,

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the things that we can's see,
we also can't understand.

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Gravity is one thing that we can't see,
and which we don't understand.

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It's the least understood
of all the four fundamental forces,

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and the weakest, and nobody really
knows what it is or why it's there.

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For what it's worth, Sir Isaac Newton,
the greatest scientist who ever lived,

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he thought Jesus came
to Earth specifically

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to operate the levers of gravity.

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That's what he thought he was there for.

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So, bright guy, could be wrong
on that one, I don't know.

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(Laughter)

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Consciousness. I see all your faces;
I've no idea what any of you are thinking.

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Isn't that amazing?

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Isn't it incredible that we can't read
each other's minds,

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when we can touch each other,
taste each other,

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perhaps, if we get close enough,
but we can't read each other's minds.

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I find that quite astonishing.

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In the Sufi faith,
this great Middle Eastern religion

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which some claim
is the root of all religions,

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Sufi masters are
all telepaths, so they say,

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but their main exercise of telepathy

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is to send out powerful signals
to the rest of us that it doesn't exist.

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So that's why we don't think it exists;
the Sufi masters working on us.

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In the question of consciousness
and artificial intelligence,

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artificial intelligence has really,
like the study of consciousness,

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gotten nowhere, we have no idea
how consciousness works.

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Not only have they not created
artificial intelligence,

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they haven't yet created
artificial stupidity.

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(Laughter)

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The laws of physics: invisible,
eternal, omnipresent, all powerful.

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Remind you of anyone?

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Interesting.

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I'm, as you can guess,
not a materialist, I'm an immaterialist.

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And I've found a very useful
new word -- ignostic.

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Okay? I'm an ignostic.

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[God?]

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I refuse to be drawn on the question
on whether God exists

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until somebody properly defines the terms.

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Another thing we can't see
is the human genome.

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And this is increasingly peculiar,
because about 20 years ago

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when they started delving into the genome,
they thought it would probably contain

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around 100 thousand genes.

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Every year since,
it's been revised downwards.

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We now think there are likely
to be just over 20 thousand genes

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in the human genome.

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This is extraordinary,
because rice -- get this --

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rice is known to have 38 thousand genes.

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Potatoes have 48 chromosomes,
two more than people,

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and the same as a gorilla.

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(Laughter)

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You can't see these things,
but they are very strange.

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The stars by day, I always
think that's fascinating.

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The universe disappears.

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The more light there is,
the less you can see.

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Time. Nobody can see time.

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I don't know if you know this.

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There's a big movement in modern physics

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to decide that time doesn't really exist,

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because it's too inconvenient
for the figures.

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It's much easier if it's not really there.

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You can't see the future, obviously,

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and you can't see the past,
except in your memory.

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One of the interesting
things about the past

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is you particularly can't see --

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my son asked me this the other day,

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"Dad, can you remember
what I was like when I was two?

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And I said, "Yes." He said, "Why can't I?"

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Isn't that extraordinary?

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You cannot remember what happened to you
earlier than the age of two or three.

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Which is great news for psychoanalysts,
because otherwise they'd be out of a job.

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Because that's where all the stuff happens

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(Laughter)

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that makes you who you are.

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Another thing you can't see
is the grid on which we hang.

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This is fascinating.

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You probably know, some of you,
that cells are continually renewed.

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Skin flakes off, hairs grow,
nails, that kind of stuff --

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but every cell in your body
is replaced at some point.

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Taste buds, every ten days or so.

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Livers and internal organs
take a bit longer.

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Spine takes several years.

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But at the end of seven years,
not one cell in your body

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remains from what was there
seven years ago.

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The question is:
who then are we? What are we?

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What is this thing that we hang on?

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That is actually us?

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Atoms, can't see them. Nobody ever will.

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They're smaller
than the wavelength of light.

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Gas, can't see that.

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Interesting, somebody
mentioned 1600 recently.

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Gas was invented in 1600
by a Dutch chemist called van Helmont.

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It's said to be the most successful ever
invention of a word by a known individual.

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Quite good. He also invented a word
called "blas," meaning astral radiation.

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Didn't catch on, unfortunately.

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(Laughter)

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But well done, him.

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Light -- you can't see light.

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When it's dark, in a vacuum,

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if a person shines a beam of light

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straight across your eyes,
you won't see it.

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Slightly technical, some physicists
will disagree with this.

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But it's odd that you can't see
the beam of light,

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you can only see what it hits.

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Electricity, can't see that.

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Don't let anyone tell you
they understand electricity, they don't.

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Nobody knows what it is.

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(Laughter)

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You probably think the electrons
in an electric wire move instantaneously

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down a wire, don't you,
at the speed of light,

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when you turn the light on, they don't.

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Electrons bumble down the wire,

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about the speed of spreading
honey, they say.

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Galaxies -- hundred billion of them,

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estimated in the universe.
Hundred billion.

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How many can we see?

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Five. Five, out of a hundred billion
galaxies, with the naked eye.

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And one of them is quite difficult to see,
unless you've got very good eyesight.

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Radio waves. There's another thing.

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Heinrich Hertz, when he discovered
radio waves, in 1887,

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he called them radio waves
because they radiated.

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Somebody said to him,
"What's the point of these, Heinrich?

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What's the point of these radio waves
that you've found?"

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And he said, "Well, I've no idea,

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but I guess somebody will find
a use for them someday.

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The biggest thing that's invisible
to us is what we don't know.

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It is incredible how little we know.

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Thomas Edison once said,

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"We don't know one percent
of one millionth about anything."

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And I've come to the conclusion --

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because you ask this other question:
"What's another thing we can't see?"

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The point, most of us. What's the point?

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The point -- what I've got it down to

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is there are only two questions
really worth asking.

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"Why are we here?",

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and "What should
we do about it while we are?"

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To help you, I've got two things to leave
you with, from two great philosophers,

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perhaps two of the greatest philosopher
thinkers of the 20th century.

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One a mathematician and engineer,
and the other a poet.

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The first is Ludwig Wittgenstein,

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who said, "I don't know why we are here,

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but I am pretty sure it's not
in order to enjoy ourselves."

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(Laughter)

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He was a cheerful bastard, wasn't he?

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(Laughter)

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And secondly, and lastly,
W.H. Auden, one of my favorite poets,

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who said, "We are here
on Earth to help others.

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What the others
are here for, I've no idea."

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(Laughter)

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(Applause)

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(Circus music)

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[Get your souvenir photo here!]

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[Continue your journey into the unknown!]

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(Circus music)