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.

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As we surveyed the galaxy for signs of life and send out our first hello anyone there signals,

there is some concern we might end up attracting the attention of someone we should have hidden from, but what if

the aliens are more scared of us than we are of them? So today we're back to the Alien Civilization series for a look at Paranoid aliens,

and we should probably start by asking what paranoia actually is.

When you're getting out on the galactic stage, it probably pays to be cautious, especially

if you think the galaxy is full of unfriendly sorts.

For today, we'll define paranoia as when you're constantly choosing the more cautious

and fear-motivated approaches to problems, over other ones which

might also be reasonable. For instance, we currently look up in the night sky and don't see

any clear evidence of other civilizations. That is the Fermi paradox, the apparent contradiction

between the size and age of the universe, and the seeming absence of any older and bigger

civilizations in it, and of courseing absence of any older and bigger civilizations

in it, and of course is one of our most common topics here on the show. Looking at that

emptiness, you might conclude you had the galaxy to yourself, or that lots of folks are

out there but you just can't see them for some reason. At first glance, that would imply

a cautious approach to stepping out from our crater world

...