Loneliness is a recent invention | Telmo Pievani | TEDxLakeComo

Among so many other things, Telmo Pievani is a thinker, professor of philosophy of science at the University of Milano-Bicocca, author of a great number of publications and director of Pikaia, the Italian portal of evolution (www.pikaia.eu)

This talk was given at a TEDx event using the TED conference format but independently organized by a local community.

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Evolution is possibly the field of science

that tells the most stories.

It tells a lot of stories,

but unlike the myths and tales
we tell children

we try to reconstruct them
using evidence, facts and signs.

A bit like Sherlock Holmes.

But stories, we know, are slippery:
they have pros and cons.

They can fascinate us,
but they can also deceive us.

They may present us
with false reconstructions.

Many years ago, a colleague of mine,
far more illustrious than me --

his name was J.B.S. Haldane,

and he was one of the fathers
of population genetics --

was in a very formal salon in Oxford

in the presence of theologians,
ladies and princesses.

And one of the ladies asked him,

"Excuse me, Professor Haldane,

but if you were to imagine the Creator,

how would you see him?
How do you picture him?"

It was a somewhat loaded question

because Haldane was known to be
an atheist, a disbeliever, a communist.

He was a bit of an oddball,
especially in England in those days.

And Haldane replied,

"Look, ma'am, I don't know.

But if I were to imagine the Creator,

I think he has

an inordinate passion for beetles."

What did Haldane mean?

He meant that if we look
at the earth and biodiversity

from an evolutionist's point of view,

the first thing we notice

is that we are at the edge
of the empire,

we are not at the centre of this story.

We are one of the many wonderful species
created by natural history.

The story I'm about to tell you
is the result of very recent research.

So let me tell you what we discovered
but a few months ago

and decisively disrupted our way
of telling the story of human evolution.

Basically, it is the story
of a disappointment,

but a constructive disappointment,
a disappointment that is good for us,

that makes us think,

that once more sets in motion

the great questions
that science is able to raise.

Where do we come from?
Why? What are we doing here?

What is the place of man in nature?

The beginning of the story
is in this image that you see behind me.

It is a fascinating, mysterious page
written by Charles Darwin himself,

dating back to July 1837.

If you remember the dates,
it means he was very young.

He was born in 1809,
he was not yet thirty.

He had just returned

from a wonderful five-year voyage
around the world, which we've all studied.

He came back in 1836
and, as soon as he got back,

he began writing
in these private notebooks.

Very private.

So secret that they were
to practically become

the only Darwinian writing
that he decided never to publish.

He is known to have said,

"I entreat you never to circulate

what I wrote as a boy
just back from my voyage."

On one of these pages,

there is this beautiful diagram
that he called The Tree of Life.

And he wrote, see, "I think…",

because, for the first time,
he was writing to himself,

he was talking to himself about
what he'd understood about evolution.

That is, evolution is a tree

and like a tree it has a trunk,
so common ancestors,

and then it has ramifications,

species that diversify over time

and then become extinct,
that multiply and so on.

An interesting story, a plural story,
made up of many different species.

Why am I telling you a story
that is actually a disappointment?

It is because when we applied
this Darwinian idea --

already back in 1837,
then he became famous,

and 20 years later he published
"On the Origin of Species" --

when we dealed with human evolution,

scientists themselves
actually made an exception.

And I say scientists themselves,
not lay people or opponents of evolution.

And if you look at how Thomas Henry Huxley
reconstructed human evolution,

you'll see that it's very different
from the tree I showed you before.

The first was a story
of diversity, of multiplicity,

of coexistence of different species.

This is a very different story,

where there's only one species at a time,
we proceed in a linear fashion.

This is a great story of progress.

It's what a colleague of mine,

who was very important in my training,

his name was Stephen Jay Gould,

called "our great illusion".

The illusion that Homo Sapiens,

who is always placed at the end,
at the far right,

should represent
the culmination of evolution.

The illusion that the Story
should necessarily lead to us.

Surely this image
is very familiar to all of us.

We always come across it,
in newspapers, on television,

we have seen it many a time.

What we have recently discovered
is that this exception is not valid.

It's been proved wrong,
we've called it into question.

Human evolution
did not take place that way.

I'll show you other
alternatives to this image

that is used in advertising,
it is used everywhere.

My favourite one is that one
at the top right corner.

It appeared in a feminist magazine

and it compares the slow and gradual
but progressive evolution of the male

with that of the female,
very stable actually.

I've found all sorts
of variants of this image.

It's a sort of major icon.

An iconography.

Even today, when we publish articles
on human evolution in newspapers

they always illustrate it with this image.

It also happened to me recently.

The first line of my article was,
"There are no missing links in evolution."

And they accompanied it with this image
showing the missing links of evolution.

So it's something very powerful,
deeply rooted in our minds.

The version that I definitely choose
as the absolute best in the world

is this one that was proposed
in The Simpsons

where evolution culminates inexorably
and wonderfully in Homersapiens,

whom you see at the far right.

Why is this exception very strange?

Because while we kept on upholding
this great iconography of hope,

scientists forged ahead

and rewrote the evolutionary stories,
the natural stories of the species

in a very different way.

This image is less easy to understand
than the previous ones

but it is wonderful.

Let me tell you one thing:

I think that if an alien
were to fall to Earth

and we were to tell him

about one of the great achievements
of science and knowledge --

yes, true, we have
the theory of relativity

and a lot of discoveries
in the field of physics

but I'd show him this picture,

and say "Thanks to science,

the species Homo sapiens
has managed to do one thing:

it's managed to assemble
and reconstruct the Tree of Life,

that is, to decode kinship
across all living beings,

but really all of them, from bacteria
up to the most complex animal,

up to the jaguar, the giraffe,
to the humans

who have inhabited
and do inhabit now this planet.

This Tree of Life brings together
all the living beings we know."

And you see that it is a tree,

it has many branches,
there are many species.

If you want to find yourself,
it is extremely complicated

because we're here,
the animals in here,

and we happen to be closer related
to mushrooms than to plants,

another thing we don't really like.

And among animals

you have to go from twig
to twig to twig for nine times

before you find Homo sapiens.

In other words, we're at the edge
of the biodiversity empire

as Haldane said with that funny quip
when he wanted to shock the lady.

The same thing holds true
if we approach our personal history,

that of our family: we find
the same pattern, can you see?

I don't want to go into this
because it is a bit too technical,

but if you look at this image
we are here, we are this species,

we are in this genus, the genus Homo.

If you look back, you find a story
of major ramifications like these.

What you find is a bush, not a ladder.

You don't find linearity,
you find multiplicity.

And interestingly,
if you look at such schemes

and you draw any time line --

imagine you have a time machine,

choose any epoch,
10 million years ago, for example,

and draw the line --

you will discover that at any time
of evolutionary history

there were many different species
existing at the same time,

more or less related to one another.

Here you see that if you start from today,

Homo Sapiens shares
a common ancestor with chimpanzees

who lived some 6/7 million years ago,

and going further back
he shares one with gorillas,

with orangutans, gibbons
and with all the other living beings,

so this is a very synthetic,
very powerful image.

Why was this powerful image
of evolution called into question?

As is often the case in science,
there's a bit of inertia,

new ideas sometimes have
a hard time to be accepted,

then one is submerged by anomalies.

That model didn't work and in the end,
though reluctantly, we abandoned it.

This is a beautiful discovery
made in 2009,

and it is so important that Science
devoted no less than two covers to it.

So, the most important discovery of 2009
is our possible ancestor called Ardi,

from Ardipithecus.

If you look closely at it,

you can see that it has a mix
of modern and archaic features.

It is a bit ape-like as you can see
from its very long upper limbs

and its divergent big toe,

yet it is perfectly bipedal,
with a flat face

and therefore presents
a mix of characters.

Now, interestingly, we discovered

that our ancestor wasn't to be placed

at the beginning
of the evolutionary process

but lived at the same time as others.

Look, this is pretty incredible.

This is a valley in Ethiopia,
a single valley in Ethiopia.

We Sapiens also originated
in that area, in one of those valleys.

In just one of these valleys

there were no less
than three different human genera,

here shown in different colours,

and none of them happened to disappear
or be replaced by another one.

They simply lived together in a bushy way.

Some died out, some new species appeared

and that complicated
and interesting image of evolution,

which concerns us directly, was created.

So this is how my colleagues and I
rebuilt human evolution.

See, time flows from bottom to top.

It's a real bush.

You see that from the days
of our common ancestor with chimpanzees

there have been about 20, maybe even 22,
some even say 25 different species.

That's anything but a linear evolution.

It's a lot more complicated,

there's loads of different species.

Even here, wherever you draw a line,
you find a lot of species coexisting.

What we have recently found out,
in the last year and a half,

and what actually shocked us
as we hadn't been expecting it,

is that this is true
even in very recent times.

If you look here,

Homo sapiens is at the top right
and we are the last twig, this one.

This is the present.

If you just go a little back in time,
even only 40/50,000 years,

you discover that there were
other human species on Earth.

And we have recently found out

that up to 30, 35, 40,000
years ago at most, mind you,

five human species coexisted on Earth,
at the same time.

That's something we hardly figure out:
five different human species!

If an alien had fallen to Earth
40,000 years ago,

he would have seen us Sapiens

roam around with four other human forms.

This, of course, opens up
many important and intriguing questions.

This is one of the latest discoveries,

made in Indonesia
on a small island called Flores.

We found storks 1.80 m tall,

mice 1.50 m long, tail included,

and small Hominini,
which hardly ever exceeded 1 m in height.

This is a relative of ours,
a cousin of ours,

discovered a few years ago on this island

where it had been stuck
for hundreds of thousands of years,

and had become very short.

This is an evolutionary mechanism called
insular dwarfism and it often occurs.

It also occurred in Italy.

As you may know,
dwarf elephants lived in Sicily,

they were as big as a large dog.

Dwarf mammoths lived in Sardinia.

This is because when large
warm-blooded species get stuck on islands,

it is better for them to become smaller,
in terms of natural selection.

But incredibly, this is the first time

that we see this occurring
in a human species.

But even more shockingly,

so much so that it took us a few years
before we actually accepted the fact,

this specimen here,

immediately called
Hobbit Man, by scientists,

that Hobbit Man on that island, Flores,

carried on and survived
until 12,000 years ago,

the day before yesterday.

At school, almost all of us studied
the Egyptians, the Sumerians,

the civilizations who invented
writing, the pyramids.

Take the pyramids, go back
a few thousand years

and on Earth there was
another human species, related to us,

with whom we coexisted

and whom we also met
as we actually visited that island.

We know that because Homo Sapiens

went in Australia
long before their extinction.

And we also know that we met,
we saw each other.

But there have been even more shocking
close encounters of the prehistoric type.

This is the latest discovery;
the paper is from April 2010.

In short, in a cave in the Altai mountains
in southern Siberia, on Asia,

we identified another human species
whose existence we had had no inkling of.

We knew that this cave, the Denisova cave,
had already been inhabited by two species:

we the Sapiens,
already 40/50,000 years ago,

and the famous Neanderthals,
we've all studied about at school.

You know that Neanderthal
was not an ancestor of ours,

he was a cousin of ours.

We coexisted with him:

even here in Italy,
in these valleys, in these areas

there were villages inhabited by Sapiens
and others by Neanderthals.

We probably communicated,
maybe we even swapped technologies.

There are sites where
sometimes an innovation,

which had already appeared
in a Sapiens settlement,

was then found in
a Neanderthal one and vice versa.

This shows that there was an interaction.

Our evolutionary history
is checkered with alter egos.

We have never been alone.

We've been alone on this planet
for a very short time indeed.

And in that cave,
scientists expected to find remains

of either Sapiens or Neanderthals
or possibly both of them.

They took a little finger,
a phalanx, from a skeleton,

brought it back to Germany
and extracted its DNA.

That can be done today: we don't live
in Jurassic Park, but it can be done!

You extract the DNA
and see which species it belongs to.

It turned out it belonged
to neither Sapiens nor Neanderthal

but to yet another species.

So a very complex history of coexistence.

You must be wondering about
something that we are all curious about,

because evolution, Gould said it himself,
is a story of death and sex

and we're always very interested in both.

Well, we don't know what caused
these species to disappear, to die out.

They all became extinct very recently,

and I know that you suspect we might
have had something to do with this.

We probably did play a role
in their extinction,

but we don't know exactly how,
as nothing dramatic happened.

We can state for sure,
it was not a genocide.

We did not kill them off directly.

Something else must have happened
that led to their progressive regression.

The fact is that, recently,

we became the only human species
left on the planet.

Then there is the sex side
and this is also surprising.

Up to a few months ago

I would have told you that
different species could not interbreed.

We thought there was a genetic barrier.

But the last discovery we made
proved that this was not the case.

Actually, all non-African Sapiens,

that is those who came out of Africa
and remained out of Africa,

probably have a 4 to 6% proportion
of Neanderthal traces in their blood.

So we carry some traces
of Neanderthal DNA in our blood.

How is that possible?

The only explanation, or at any rate,
the most plausible explanation

is that at least at some time in the past,
possibly in the Middle East for some,

for 10/15 thousand years
we may have mated.

We had fertile matings,
so the two species interbred for a while,

then they separated, one of them died out
and we Sapiens had the upper hand.

But this is a dogma that is refuted
because our genome is not only ours,

so we must not be too jealous.

It is a cloak of Harlequin

in which there are traces
of other species.

We are not alone, not even in our genome.

I'm now showing you this image
because we came out of here.

This is another very recent fact:
the strait of Djibouti.

Populations of the Sapiens
crossed this small passage,

and then met the other species
that had left earlier:

the Neanderthals, the Denisovans
I have just shown you,

and then the Indonesian species.

This is a summary
of everything I have told you:

we ventured out of Africa,

we did so repeatedly
from 100/120,000 years ago

and when we came out,
we met other existing living forms,

human species related to us.

We coexisted, we sometimes mated
and then we colonized the whole world.

We're the only one, for example,

who arrived in Australia
and then colonized the Americas,

because in the ice ages
the world was different

from what it appears to be like here.

There were entire continents
that are now submerged, like Beringia,

or this whole area which was passable.

So you could get there
without crossing the sea

from South Africa to South America.

One of the consequences, of course,
of this whole story

is, first, that perhaps

we need to look at evolution
with a little more humility,

without thinking of ourselves
as the ultimate end,

especially since we interbred.

And interestingly,

but I'm saying it only now, in closing,
because I didn't want to shock anyone,

we also know that the interbreeding
was asymmetrical.

It was always a Neanderthal male
with a Sapiens female.

That for us Sapiens boys
is really disheartening

(Laughter)

because we had our females
stolen from us 40,000 years ago already,

so evolution punched us in the stomach.

But the second consequence
is more serious:

if this is our history,

then what we have always called
"human races" do not actually exist.

We are a young species,

we all come from a very small group

and there was no time
to separate human races.

So let's delete the concept of human race
from the language of science.

Thank you!

(Applause)