Chapter 2: The Tree of Knowledge

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You ever stop and think about how we homo sapiens ended up as the dominant species on this planet?

It is pretty staggering when you consider it.

For hundreds of thousands of years, we were basically just another primate hanging around in East Africa.

And then, boom, around 70 ,000 years ago, something happens.

Something shifts dramatically.

Right.

And suddenly we're spreading like wildfire.

And while the other human species just sort of fade out, you have to wonder, what was our edge?

What changed?

And that exact question, why us, is really what we're diving into today.

The core concept that tries to explain this, based on the chapter we're looking at, is the cognitive revolution.

The cognitive revolution, okay.

Think of it like a massive software update for our ancestors' brains.

A kind of blooming of these unique capabilities in sapiens, mostly between, say, 70 ,000, 30 ,000 years ago.

And we're not talking about a minor patch here, are we?

No, no.

This was fundamental.

It changed how we thought, how we communicated, how we worked together.

I mean, it's the foundation for pretty much everything that came after cities,

nations, technology.

And the really wild part you hinted at is that a key ingredient in all this was, well, fiction,

stories.

Exactly.

The power of things that aren't actually real, in an objective sense.

But yeah, let's unpack that.

First, we need to set the stage.

Okay.

So before this revolution kicked off.

Right.

So go back to around, say, 150 ,000 years ago.

Sapiens are in East Africa.

Physically, they look like us.

Crucially, their brains are the same size as ours.

Same hardware, basically.

Same hardware.

But here's the thing.

For tens of thousands of years, they didn't seem to do anything particularly special.

They're tools.

They're achievements.

They weren't really standing out from Neanderthals or other human species around at the time.

It's kind of humbling, isn't it?

And did they even try to move out of Africa earlier?

They did.

There was an earlier migration attempt up into the Levant, maybe around 100 ,000 years ago.

How did that go?

Not well.

They ran into Neanderthals who were already established there.

And basically, the Sapiens got pushed back.

They couldn't get a foothold.

So Neanderthals held their ground.

That really suggests something was different back then, cognitively, maybe.

It strongly implies it.

The speculation is that while those early Sapiens had the anatomy,

the internal wiring of their brains might have been different.

Maybe less capacity for complex learning, remembering stuff, communicating really sophisticated ideas.

Like having the computer case and the chip, but a really basic operating system.

That's a great analogy.

All the potential, perhaps, but limited in what it could actually do.

Okay.

But then, around 70 ,000 years ago,

the game changes completely.

It's like that new operating system finally gets installed.

Yes.

Sapiens leave Africa again, this second wave.

And this time, it's different.

They don't just trickle out.

They surge across the entire globe.

Wow.

And this is when they start displacing the other human species.

Exactly.

This second migration coincides with the start of this incredible expansion.

They spread everywhere.

Europe, East Asia.

And get this, by about 45 ,000 years ago, they even managed to cross open sea to reach Australia.

Open sea, 45 ,000 years ago.

Something no other human species had ever done.

It points to a whole new level of planning, cooperation, and probably technology.

And it wasn't just migration, right?

This whole period, 70 ,000 down to 30 ,000 years ago, it's like an invention explosion.

It really is.

You see the first solid evidence for boats.

Imagine what that opened up.

Oil lamps changing life after dark.

Bows and arrows, a revolution in hunting.

Needles.

Needles sound small, but crucial for tailored clothing, right?

Surviving colder places.

Absolutely.

Essential for expanding into new environments.

And beyond tools, we see the first really clear signs of other complex stuff.

Like what?

Like religion evidence of rituals, shared beliefs, calmer signs of trade between groups.

Even the beginnings of social stratification.

You know, different roles.

Maybe hierarchies.

So the migrations, the inventions, the social changes.

The main theory is that this all stems from that cognitive upgrade.

That revolution in how sapiens could think.

That's the prevailing theory, yes.

A fundamental shift in cognitive abilities.

And it's important to stress these sapiens, the ones making boats and art and forming complex societies.

They were likely just as intelligent, creative, and emotionally complex as we are today.

Same basic mental hardware, but now running much more powerful software.

So the million dollar question then, what caused it?

This tree of knowledge mutation, as the chapter terms it.

Was it just luck?

That's the mystery, isn't it?

The most common explanation points towards accidental genetic mutations.

Just random changes in DNA that happen to rewire the sapiens brain in just the right way.

Giving us new ways to think, new ways to communicate.

Exactly.

Unprecedented ways.

Why it happened in sapiens and not, say, Neanderthals who were clearly intelligent too.

We don't know.

Maybe it was just a fluke, a lucky break in our lineage.

But the consequences of that break, that's what changed everything.

Precisely.

The consequences were revolutionary.

Which brings us to the new language.

Okay, so what was so special about this new sapiens language?

Because animals communicate all the time, right?

Bees dance, monkeys have warning calls.

Absolutely.

Communication isn't unique to us.

And it wasn't even the first vocal language.

Green monkeys have different calls for eagle or leopard.

Whales sing, elephants rumble, parrots can mimic human speech perfectly.

Yeah, a parrot could repeat Einstein, but it wouldn't understand Einstein.

Exactly.

So the innovation wasn't just making sounds.

So what was the big upgrade then?

The first key thing was its incredible flexibility, its suppleness.

Our language allowed us to combine a limited number of sounds or signs into basically an infinite number of sentences.

Infinite sentences.

Pretty much.

Each with a distinct meaning.

This meant we could suddenly receive, store, and communicate a massive amount of information about the world around us.

Way more than just leopard.

Yeah, give me an example.

How does it play out practically?

Okay, so the monkey call is just leopard.

Immediate danger, simple signal, very useful, but limited.

A human, using this new language, could say something much more complex.

Like, careful.

Yesterday morning, down by the riverbend, I saw a lion stalking some bison near that big tree.

Ah, okay.

So much more detail.

Time, place, context, what was happening.

Exactly.

Location, participants,

actions, even potential future actions.

And with that kind of detailed information, a group could discuss it, analyze it, plan strategies, how to avoid the lion, or maybe even how to coordinate a hunt for those bison.

It enables complex planning and collective action based on shared knowledge.

That makes a lot of sense.

It's about the richness of the information.

But there's another theory about language evolution, isn't there?

Something more.

Gossipy.

Yes.

The second major theory is often called the gossip theory.

And it's quite compelling.

It suggests that our language evolved primarily not just to talk about lions and bison, but to talk about ourselves.

About other humans.

Gossip.

As a driving force for language.

Think about it.

We're intensely social animals.

Our survival and reproductive success have always depended heavily on cooperation within our group.

Sure.

You need to work together.

But cooperation requires knowing who's who.

Who can you trust?

Who's a reliable partner?

Who's likely to cheat or slack off?

Who's allied with whom?

Who owes favors?

All that social calculation stuff.

Who's sleeping with whom?

Who hates whom?

Exactly.

Knowing the social landscape is vital.

Now try tracking all those relationships in a group.

Even in a band of just 50 people, there are over a thousand one -on -one relationships to keep tabs on.

Wow.

Okay.

That's a lot of social data to manage.

It is.

And while other primates are certainly interested in social dynamics, their ability to share that information effectively seems limited.

Our new linguistic skills, the theory goes, allowed us to gossip efficiently.

So talking about each other helped us build trust and cohesion.

Precisely.

By sharing information about reputations, who's honest, who's lazy, who's dangerous, sapiens could maintain cooperation in larger groups than ever before.

If everyone knows someone is unreliable, they can avoid cooperating with them, or at least be cautious.

Gossip functions as a kind of social policing mechanism.

It allows groups to grow beyond the size where everyone knows everyone else intimately.

Exactly.

It helps maintain social order and cohesion, enabling larger bands, up to maybe 150 individuals,

according to some studies,

and fostering more complex forms of cooperation.

And it's funny because even today, so much of our communication is basically gossip, isn't it?

Emails, phone calls, news reports, social media.

Yeah.

It's often about what other people are doing.

It really is.

Think about academics at a conference.

Sure, they talk research, but they also talk about who got funding, who's feuding with whom, departmental politics.

It's human nature.

Gossip helps us map our social world and enforce its norms.

So it's probably not either, right?

Language likely evolved both for sharing information about the world and for navigating our social lives.

Most likely, yes.

The two functions probably reinforced each other.

Being able to talk about both lions and liars was crucial.

Okay, so we have the super flexible language for talking about the real world and our social world, but then comes the really weird part.

The part that seems uniquely human.

Talking about things that, well, that aren't real.

This is arguably the most feature of Sapien's language.

The true game changer that came with the cognitive revolution.

The ability to transmit information about things that don't actually exist in any objective sense.

Like legends, myths, gods, spirits.

Exactly.

Things we can't see, touch, or empirically verify.

Think about the difference.

A monkey can maybe signal, careful,

a lion,

but only a human can say, the lion is the guardian spirit of our tribe.

Right.

One is about immediate, tangible reality.

The other is about a shared belief,

an abstraction.

Precisely.

And at first glance, you might think, well, how is that useful for survival?

Spending time talking about spirits seems less practical than finding food or avoiding predators, doesn't it?

Yeah, that's what I was wondering.

Wouldn't evolution favor the practical realists over the storytellers?

Seems counterintuitive.

But the incredible advantage wasn't just talking about fiction.

It was the ability to create shared fictions, collective imagination.

Shared fictions, like common myths.

Yes.

Creation stories, tribal totems, national myths, religious doctrines.

These shared stories, these common myths that everyone in the group believes in, they achieve something unprecedented.

Which is?

They allow sapiens to cooperate flexibly in massive numbers, even with complete strangers.

Ah, okay.

That's the connection.

Because everyone believes in the same story.

Exactly.

Think about other social animals.

Ants and bees cooperate in huge numbers, but it's rigid, genetically programmed cooperation.

They can't suddenly decide to overthrow the queen and establish a republic.

Right.

It's hardwired.

And chimpanzees or wolves cooperate, but usually only in small, intimate groups where everyone knows each other personally.

Their cooperation is flexible, but limited in scale.

So sapiens crack the code.

Flexible cooperation on a massive scale.

Yes.

By uniting potentially millions of strangers around common myths and fictions, like a belief in a god, or a nation, or human rights, or even money sapiens could achieve feats of coordination impossible for any other animal.

And that ability to cooperate flexibly with countless strangers, as the chapter argues, is the fundamental secret to our species' dominance.

That's a powerful idea.

That our ability to believe in stories is what lets us rule the world.

It underpins so much of human society.

And the example the chapter uses to illustrate this in the modern world is really effective.

The Peugeot Car Company.

Right.

Peugeot SA.

How does that illustrate this idea of shared fiction?

Well, think about it.

Peugeot started as a small family business.

Interestingly, near the Statle Cave, where that ancient lion man sculpture itself evidence of early human imagination was found, now is this huge multinational corporation.

Employing hundreds of thousands of people worldwide, most of whom have never met.

Exactly.

They all cooperate in complex ways to design, build, and sell cars.

But in what sense does Peugeot SA actually exist?

Well, it's not just the cars, obviously.

Or the factories, or the machines.

No.

If all the Peugeot factories burned down and all the cars rusted away, the company, Peugeot SA, could still exist.

It could borrow money, hire new people, build new factories.

It's not the employees either, or the managers, or even the shareholders, people come and go.

Right.

It could fire every employee and sell all its assets.

And the legal entity might still remain.

Perhaps just as a shell company on paper.

It could even be dissolved entirely through legal procedures, even if all the physical parts and people remained.

So it exists because we all sort of agree it exists.

Because the legal system says it exists.

Precisely.

It's what lawyers call a legal fiction.

It's an entity created purely by our collective belief in legal frameworks.

It's not a physical object, you can't point to it, but it has legal rights and responsibilities.

It can own property, pay taxes, enter contracts, sue and be sued.

Just like a person, in some ways.

Exactly.

It's treated as a legal person, separate from the actual humans involved.

And this specific type of fiction, the Limited Liability Company, was a revolutionary invention in itself.

How so?

What did that change?

Well, for most of history, if you owned a business, you were personally liable for its debts.

If the business failed, creditors could come after your house, your personal savings, everything.

That sounds incredibly risky.

It would make anyone hesitant to start a big venture.

It absolutely did.

The invention of limited liability meant that the company itself was liable for its debts.

But the personal assets of the owners or shareholders were protected.

If the company went bankrupt, they'd lose their investment in the company, but not their house.

I see.

So believing in this fiction of the separate company actually encouraged people to take bigger risks, to invest, to start businesses, it spurred economic activity.

Massively.

It unleashed entrepreneurial energy because the potential downside was limited.

We collectively imagined this entity, gave it legal standing, and that shared belief transformed the economic landscape.

We're surrounded by these corporate fictions now.

They're incredibly powerful forces in our world.

And the chapter makes this interesting comparison, doesn't it, between creating a company and a religious ritual.

Yes, it draws a parallel between Armand Peugeot going through the legal steps to create Peugeot Essay, signing documents following procedures, and a priest performing the rights to, say, consecrate bread and wine in Catholicism.

Both involve following a specific formula, a set of rules based on a shared story, to bring something into existence in the minds of the believers.

Exactly.

In both cases, the power lies not in the physical actions themselves, but in the collective belief that those actions performed correctly according to the story have a real effect.

The tricky part always is getting enough people to believe in the story in the first place.

So history, in a way, is about how these stories get told and how they convince people.

That's a big part of it.

How are these shared beliefs, these fictions, social constructs, imagined realities, created, spread, and maintained?

And crucially, they aren't necessarily lies.

Most people believe in nations or money or human rights.

That collective belief is what gives them their power.

So we live in this kind of dual reality then, the objective reality of rivers, trees, lions, and this overlaid reality of imagined things like gods, nations, corporations.

Precisely.

And over time, that imagined reality has become incredibly powerful, often shaping our interactions with and even altering the objective reality.

And this ability, this power of imagined realities, it didn't just allow for large -scale cooperation, it also allowed for something else crucial, right?

Rapid change.

Yes, that's the other huge consequence.

It allowed for incredibly fast cultural evolution.

It let us bypass the slow, grinding pace of genetic evolution.

How does changing a story speed things up compared to changing genes?

Because if your cooperation is based on a shared myth, you can change the cooperation patterns simply by changing the myth.

You don't need to wait generations for genetic mutations to alter behavior.

Like the French Revolution example.

Exactly.

In a very short time, the dominant story in France shifted from the divine right of kings to the sovereignty of the people.

The French didn't suddenly develop new genes for democracy.

They just changed the story they collectively believed in, and their entire social and political structure transformed almost overnight.

Whereas other animals are much more bound by their biology.

Think about chimpanzees and bonobos.

They have different social structures.

Chimps more hierarchical, bonobos more egalitarian.

But that's largely rooted in their genetics.

You won't see a chimp troop suddenly deciding, let's try the bonobo way for a few decades.

They're stuck with their biological programming, more or less.

To a much greater extent, yes.

Their behavior patterns can change, but typically only very slowly, often linked to genetic or major environmental shifts.

But sapiens.

We can completely overhaul our social structures, our economies, our beliefs, within decades or even years, just by changing the stories we tell and believe.

And you see this even in behaviors that seem to go against biological imperatives, like those childless elites, priests, monks, eunuchs.

That's a fascinating example.

From a purely genetic perspective, dedicating your life to celibacy makes no sense.

It doesn't pass on your genes.

Yet these institutions have existed for centuries.

Why?

Because of the shared stories, the beliefs, the social structures built around them.

Not because of a celibacy gene.

Exactly.

It's cultural transmission, sustained by shared fictions, completely overriding a basic biological drive.

Think about the sheer pace of change for humans.

Consider someone born in Berlin in 1900.

Right, you mentioned this.

They could have lived through an empire, a republic, a Nazi dictatorship, communism, and then reunification.

Five radically different sociopolitical systems within one lifetime.

Their DNA didn't change, but they adapted their behavior and understanding to fit entirely different sets of rules, different imagined realities.

That level of rapid adaptation is unique to sapiens.

And this adaptability, this ability to change the rules of cooperation on the fly, must have been a massive advantage against other humans, like Neanderthals, especially in conflict.

It seems highly likely.

And Neanderthal might have been stronger individually, maybe even smarter in some ways.

But imagine a conflict between a group of sapiens, united by a shared story that allows for complex strategy and rapid adaptation, versus a group of Neanderthals relying on more ingrained, perhaps less flexible social patterns.

The sapiens could potentially coordinate better, change tactics faster, maybe even rally larger numbers based on a shared identity or goal?

That's the idea.

Sapiens' ability to invent and believe in fictions gave them an edge in large -scale cooperation and adaptability that other human species likely lacked.

Is there any archaeological evidence that hints at this difference in cognitive abilities or cooperation?

There are some suggestive findings.

For example, sapien sites from tens of thousands of years ago often contained materials, like seashells or specific types of stone, that originated hundreds of kilometers away.

Indicating long -distance trade networks?

Yes, which implies not just travel, but complex social interactions, trust, and probably shared systems of value or belief to facilitate that exchange between different groups.

Neanderthal sites from the same period, they tend to show much more reliance on local materials, less evidence of these extensive networks.

Interesting.

What about hunting?

Any differences there?

Also suggestive, Neanderthals seem to have primarily hunted alone or in small familiar groups.

Sapiens, on the other hand, developed techniques for large -scale cooperative hunts.

Like driving entire herds into cliffs or traps?

Exactly, stuff that requires dozens of individuals, maybe even multiple bands working together, coordinating their actions according to a shared plan.

This implies a level of communication, planning, and social cohesion likely enabled by their advanced cognitive and linguistic abilities, possibly rooted in shared narratives.

So, when sapiens expanded and inevitably came into competition with Neanderthals for resources, Sapiens' superior ability to cooperate in large, flexible groups and to innovate and adapt their strategies likely gave them a decisive advantage over the long term.

Okay, so let's try to quickly summarize the core impacts of this cognitive revolution then.

What new abilities did we gain?

Right.

So, number one, the ability to transmit much larger quantities of information about the surrounding world.

Which led to better planning, like avoiding dangers or organizing complex hunts.

Exactly.

Number two, the ability to transmit much more information about social relationships.

The gossip factor.

What?

Leading to larger, more cohesive groups, maybe up to that 150 threshold.

Precisely.

And number three, the really unique one,

the ability to transmit information about things that don't actually exist in objective reality fictions.

And that unlocked two massive consequences, cooperation between huge numbers of strangers.

And B, the capacity for rapid innovation in social behavior.

Changing the story changes the society.

Got it.

So those imagined realities, those fictions, they are basically what we call cultures, right?

All the diverse beliefs and behaviors.

That's how the chapter frames it.

The variety of invented realities and the behaviors they inspire constitute what we know as cultures.

And history, then, is the story of how these cultures change and develop over time.

So the cognitive revolution is the point where history kind of breaks free from pure biology.

In a sense, yes.

It's the point where describing human events purely in terms of genes, hormones, and environment becomes insufficient.

To understand things like the rise of Christianity or the French Revolution, you have to understand the interplay of ideas, images,

myths,

the imagined realities.

But biology still matters, obviously.

It sets the stage.

Absolutely.

Biology provides the fundamental hardware, the basic needs, the inherent capabilities and limitations.

It's the playing field.

But history is the game that sapiens play on that field.

And the rules of that game, the strategies, the goals, those are largely determined by the imagined realities we create.

It's like focusing only on the dimensions of a football pitch without understanding the rules of football or the teams playing.

Exactly.

You'd miss the whole point of the game.

The truly significant differences between us and, say, chimpanzees become most apparent when you look at group behavior beyond small bands.

Put 1 ,000 chimps in Wall Street or Tiananmen Square and you get chaos.

Put 1 ,000 humans there and you often get ordered, coordinated activity, like trade or demonstrations.

Held together by that mythical glue, shared beliefs in money or nations or ideologies.

Yes.

That glue allows for cooperation on a scale and complexity utterly beyond any other animal.

Even our tool -making prowess, while important, depends on this cooperation.

An ancient Flint spearhead required skill, but relatively little cooperation.

Whereas a modern nuclear warhead requires the coordinated efforts of millions of people across the globe.

Miners, physicists, engineers, politicians, soldiers, most of whom we'll never meet, all working within vast, complex organizations built on shared fictions, like corporations and states.

Our ability to make tools hasn't improved that much biologically, but our ability to cooperate has exploded.

So biology sets the boundaries, but within those boundaries, history is driven by the evolution of these complex games or fictions we invent.

That sums it up nicely.

Understanding human behavior after the cognitive revolution means understanding the history of these imagined realities.

Which leaves us wondering, what were those early games like?

What was daily life like for those Stone Age sapiens running this new cognitive software for the first time?

What did they believe?

How did they organize themselves?

And that's precisely where the exploration likely heads next into the world of our hunter -gatherer ancestors after this profound transformation, but before the next major revolution reshaped human life.

So, bringing this deep dive to a close, the big takeaway is the sheer transformative power of the cognitive revolution.

It wasn't just about getting smarter, it was about getting a new kind of mind, one capable of flexible language for sharing information about the world and, crucially, about each other through gossip.

Right, that social bonding aspect was key.

But the truly unique leap was the ability to create and collectively believe in fictions, shared stories about gods, spirits, nations, money, corporations.

And that power of collective imagination is what allowed for unprecedented flexible cooperation among vast numbers of strangers.

It's the bedrock of human culture, history, and our species' eventual dominance.

And it leaves us with a pretty profound thought, doesn't it?

As we navigate our own complex world filled with powerful imagined realities like nations, economic systems, and ideologies,

what are the fictions we live by today?

And what new fictions might we be creating right now, perhaps unconsciously, that will shape the future?

A really compelling question to ponder.

What stories will define the next chapter of human history?

Indeed.

And with that, I think we've thoroughly covered the landscape of this chapter on the cognitive revolution.

We've touched on all the key ideas, the timelines like the migrations the core arguments about language, gossip, and fiction, the pivotal data points and examples like the Levant failure, Peugeot, and the Neanderthal comparisons.

We've definitely highlighted the evolutionary milestones, the significant socio -cultural shifts, and Harari's central theses about cooperation and imagined realities, exploring their implications for our past and future.

We aim for full coverage, hitting every major section from the puzzle of early sapiens right through to the relationship between history and biology.