In Sapiens, Yuval Noah Harari describes the Cognitive Revolution as a turning point between 70,000 and 30,000 years ago, when Homo Sapiens experienced significant advances in innovation, migration, and social organization. He attributes much of this progress to a new way of thinking and communicating that gave humans the unique ability to cooperate at large scales through shared fictions. This ability sets us apart from other species, which primarily cooperate through direct social interaction and gossip.

Harari explains that human language evolved not just to convey information, but also to gossip, which helped us build trust and maintain social bonds within a group. However, there is a limit to how large a group can be when it relies solely on personal relationships. For such a group to function, everyone needs to know everyone else. Sociological research suggests this kind of relationship-based cooperation has a cognitive ceiling of around 150 people. This is often referred to as Dunbar’s Number. Beyond this threshold, it becomes cognitively overwhelming for everyone to maintain direct personal relationships within the group.

What allowed us to overcome this limit was our ability to invent and believe in shared fictions. Constructs like religions, money, nations, laws, and corporations exist primarily in our collective imagination, yet they enable large-scale cooperation among strangers, as long as they believe in the same story.

The book gives a few interesting examples to illustrate this:

• Many animals, including humans, can communicate real danger, like “Careful! A lion!” But humans have the ability to say, “The lion is the guardian spirit of our tribe.”

• You could never convince a monkey to give you a banana today in exchange for an infinite supply of bananas in monkey heaven.

This idea of shared fiction, particularly how it allows for large-scale cooperation, really stuck with me. But it also got me thinking more broadly about human nature: why we cooperate, why fiction often proves more effective than truth, and whether there are limits to how far that cooperation can scale.

The Social Instinct and Group Identity

Humans are inherently social and tribal. We evolved to cooperate for survival and reproduction. We form families, communities, and nations. We’re wired to seek connection and shared meaning, which is why we often align ourselves with group identities. In doing so, we don’t always prioritize truth. Instead, we often gravitate toward narratives that reinforce our identity and strengthen social bonds.

In some domains, cooperation is grounded in a shared pursuit of truth, especially in fields like science and medicine, where progress depends on evidence, testing, and consensus. But shared fictions tend to scale more easily, not because truth is anti-social, but because it’s often inconvenient, complex, or hard to rally around. Fictions, on the other hand, can be crafted to inspire, unify, and simplify.

Can Truth Compete with Fiction?

Shared fiction simplifies large-scale cooperation, but that same flexibility makes it fragile. Because it's easy to craft, it's also easy to splinter. Different stories give rise to different groups, each believing something else. Shared truth doesn't face the same issue, as it is harder to manipulate, and in theory, it could offer a universal foundation. But the challenge is that truth is rarely convenient, often complex, and not emotionally satisfying.

I'd like to believe people could rally around something grounded in truth, where the narratives are emotionally powerful yet rooted in reality. But in practice, it's fiction that tends to win hearts.

The Limits of Unity

Is it possible to create a shared goal that unites us all as one species?

Temporarily, yes. It has happened before. When humans first landed on the Moon, people around the world watched together. It symbolized what we could achieve when acting as one. After World War II, there was a widespread hope for a more peaceful future.

Maybe it would take an existential threat to humanity to trigger that kind of unity again. Something so big and undeniable that it overrides our smaller identities. Basically... aliens.

But a lasting form of large-scale unity is hard in practice, because people naturally prioritize smaller, in-group identities. Even during moments of unity, we are often responding to a more emotionally charged event that briefly redirects attention. Once it passes, most people return to their usual affiliations.

Still, those moments show that large-scale cooperation is possible. Making it last, though, would likely require some form of cultural evolution. That might involve building institutions, social norms, and incentives that help counter the instincts that divide us.

If stories are what help us coordinate at scale, then the kinds of stories we tell matter. Fiction is often more emotionally engaging, but it's easy to create and easy to manipulate. Truth is harder to craft, but also harder to distort. Maybe the goal isn’t to choose between truth and fiction, but to learn how to communicate truth in a way that resonates emotionally.