The Fermi Paradox: Modern estimates often place hundreds or thousands of intelligent civilizations among our galaxy's hundreds of billions of stars. So why are the airwaves silent?



But where's everyone else? Maybe...

There is no one else

Maybe we are the only or one of the only civilizations in this part of the galaxy. It's a disheartening thought, to me at least. There are a number of more specific scenarios. Just a couple:

Intelligent life is very rare in general. Maybe we vastly underestimate the obstacles keeping an intelligent civilization from evolving on a given planet.

Intelligent life is very rare in our neighborhood. Maybe for some reason our neighborhood is a rural one with few advanced civilizations around. Maybe everyone just got really unlucky with gamma ray bursts or something. Still, this leaves the question, if advanced life is common elsewhere in the galaxy, why haven't they sent us an army of von Neumann probes? Maybe the engineering behind them is just too damned hard. Maybe exploring the galaxy doesn't appeal to them (but you would expect it to appeal to at least one of them, if there were many).

There really are lots of aliens

But maybe they don't want to talk to us. Maybe we're in a zoo owned by a powerful race that tries very hard to keep us ignorant of what's going on elsewhere. Maybe all races just get addicted to extremely advanced forms of electronic entertainment and don't care about anything else.

The universe isn't real

Maybe we live in a computer or some other engineered system. In this case, of course, there might be no aliens or there might be lots of them, but the engineers for some reason want to keep us apart from them.

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Occam's Razor makes me tend to believe that our predictions about how common life is are simply way too optimistic. That seems like a simpler explanation than any I've heard that posit there being lots of aliens.

The "universe isn't real" possibility is an interesting one as well since it's difficult to imagine how likely or unlikely it is, though some disagree pretty compellingly.