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. We often contemplate super-intelligent entities, and advances in AI and human mind augmentation

may soon bring them about.

But how big could they get?

What would they think about?

And might you, or I I one day become one ourselves?

A fairly common theme in both science fiction and futurism is trying to push the envelope

to imagine the biggest possible example of something, or most extreme version, and the big difference between science fiction

and futurism is that the latter does expect you to present some solid reasoning and scientific

support for the case. Today we're looking at the biggest possible computers or minds you could

build, and one of the big questions that comes up with mega minds of what they spend all their

time thinking about. Amusingly, it might be dreaming up even huger minds than themselves, and with all their

brains they ought to be able to come up with some ideas that chuckle at the ones we'll

discuss today.

My own first exposure to the topic of truly immense computers was Douglas Adams' deep thought

in the first book of his famous five-book trilogy, The Hitchhackers Guides

the Galaxy. This was an immense computer built by higher-dimensional beings, Fouk and

Lunkwill, and on being turned on and making some initial discussion and calibration, Fook begins.

Oh, deep thought computer, he said, the task we have designed you to perform is this.

We want you to tell us, he paused, the answer.

...