This is one answer to the fermi paradox that makes no sense to me. If we did live in a dark forest universe where everyone was hiding from some oppressive existential threat, how would any of the civilisations learn about it?
They would need to be in contact with one another to discover that other civilisations were being wiped out, but for that to happen, the wiping out civilisation would have to be able to find them as well. If they destroyed civ A, they'd definitely be able to find references to civ B in their ruins, somewhere. I see no mechanism by which a civilisation could observe this enemy in action without being detected.
Unless someone has come up with an answer to this issue, in which case I'd like to see it.
Also, if you can detect them, just telling them that you've detected them should change their strategy, because if a basic civilsation like ours can do it then they're not actually that safe by hiding. The dark forest seems like a really fragile arrangement.
The oppressive existential threat you reference doesn't need to exist for the universe to be a dark forest universe. It's enough for every sufficiently advanced civilization to realize that such a threat could exist and remain quiet and hidden just in case.
Right but that's fragile. All it takes is one group to break the ice and suddenly they're all talking.
Also, is the theory that we could live in a dark forest because every single species is insular enough to be afraid of such a threat? That means they all have to believe in the threat and yet also no species is aggressive enough to become the threat. But none of them thinks, "Wait, either we're alone or everyone is hiding. If everyone is hiding, then the threat can't exist, so we may as well say something."
Again, it's fragile. I find it completely unconvincing.
The Prime Directive concept is way more believable to me, as is the idea that life is just sparse.
All it takes is one civilization to shoot off their mouth and get destroyed by a much more advanced neighbor, in some way that doesn't look quite natural. That will tend to confirm the cosmic paranoia.
As I said elsewhere: that's no longer a dark forest. The moment one civilisation speaks up, they all know they're not alone. Then they're in a different universe, one where there's no longer a paradox because they've found each other.
I do agree with your probability assessment; I too think that the Prime Directive is a more plausible answer to the Fermi paradox, as is “we're just alone”.
However, it is not necessarily the case that everyone suddenly gets talking as soon as one of them breaks radio silence. If everyone is silent because of a perceived possible threat, then it stands to reason they will continue to be silent even when they receive a message.