Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asking the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and ad-free, plus hours of bonus content,

check out go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

Some civilizations build empires in which countless minds can flourish.

Others may build a single mind instead, and then forget the stars exist.

If advanced alien civilizations exist, maybe they're not quiet because they're hiding,

but because

their thoughts cannot reach across the vastness of space.

When we consider possible solutions to the Fermi paradox, why we don't see signs of extraterrestrial

intelligence, despite the age and size of the universe, we often imagine grand civilizations

stretching across the stars, or even galaxies, but what

if the pursuit of unity and intelligence leads not to expansion, but to silence?

In this episode we'll be exploring the Hive Mind Dilemma, a theory that suggests a civilization

might link all its minds together into one vast collective consciousness, but be prevented

from further expansion if such

your mind has physical limits.

Limits imposed by the speed of light, signal delay, and the sheer challenge of thinking

as one across interstellar distances.

Could it be that hive minds hit a hard ceiling on growth, where expanding beyond a planet

erodes intelligence rather than enhances it, and

seeing the stars with rivals becomes unthinkable. And if so, might that explain why

...