The Great Filter isn't magic either

I'm tempted to suggest that the field of interstellar futurology has two big questions that both have very wide error bars which each, considered one at a time, suggest the need for some other theory (outside the horizon of common reasoning) to produce an answer.

It makes me wonder how plausible it is that these questions are related, and help answer each other:

(1) How many other species are out there for us to meet?

(2) Will we will ever go out there or not?

For the first question, Occam suggests that we consider small numbers like "0" or "1", or else that we consider simple evolutionary processes that can occur everywhere and imply numbers like "many".

Observational evidence (as per Fermi) so far rules out "many".

Our own late-in-the-universe self-observing existence with plausible plans for expansion into space (which makes the answer to the second questions seem like it could be yes) suggests that 0 aliens out there is implausible... so what about just going with 1?

This 1 species would not be "AN alien race" but rather "THE alien race". They would be simply the one minimal other alien race whose existence is very strongly implied by minimal evidence plus logical reasoning.

Looping back to the second question of interstellar futurology (and following Occam and theoretical humility in trying to keep the number of theoretical elements small) perhaps the answer to whether our descendants will be visible in the skies of other species is "no with 99.99% probability" because of THE alien race.

When I hear "the zoo hypothesis" this logically simple version, without lots of details, is what I usually think of: Simply that there is "some single thing" and for some reason it makes the sky empty and forecloses our ever doing anything that would make the sky of another species NOT empty.

However, wikipedia's zoo hypothesis is full of crazy details about politics and culture and how moral progress is going to somehow make every species converge on the one clear moral rule of not being visible to any other species at our stage or below, so somehow we ourselves (and every single other species among the plausibly "many") are also in some sense "THE (culturally convergently universal) species" which is the space civilization that sprouts everywhere and inevitably convergently evolves into maintaining the intergalactic zoo.

Yeah. This is all very nice... but it seems both very detailed and kind of hilariously optimistic... like back when the Soviet Union's working theory was that of course the aliens would be socialist... and then data came in and they refused to give up on the optimism even though it no longer made sense, so they just added more epicycles and kept chugging away.

I'm reminded of the novels of Alastair Reynolds where he calls THE alien race "The Inhibitors".

Reynolds gave them all kinds of decorative details that might be excused by the demand that commercial science fiction have dramatically compelling plots... However one of their details was that they were a galactic rather than intergalactic power. This seems like a really critical strategic fact that can't be written off as a detail added for story drama, and so that detail counts against the science side of his work. Too much detail of the wrong sort!

In the spirit of theoretical completeness, consider pairing the "optimistic zoo theory" with a more "pessimistic zoo theory".

In the pessimistic version THE intergalactic alien race is going to come here and kill us. Our chance of preventing this extermination is basically "the number of stars we see that seem to have been the origin of a a visible and friendly intergalactic civilization (plus one as per Laplace's rule of succession) divided by the number of stars where a civilization with this potential could have developed".

By my count our chance of surviving using this formula would be ((0 + 1) / 10 ^ BIG).

Like if it was you versus a weed in your garden, the weed's chances of surviving you are better than humanity's chances of surviving THE aliens.

Lower? Yes! At least individual weeds evolved under the selection pressure of animal grazing, and individual weeds have a plant genome full of survival wisdom to use to fight a human weeder, who is doing something more or less similar to what grazing animals do.

So the only strong observational argument I can see against the pessimistic zoo theory is that if it were true, then to square with what we see we have to suppose that THE alien weeders would bother with camouflage that SETI can't penetrate.

Consider all the potentially valuable things they could do with the universe that would tip us off right away, and then consider the cost of being visible. Would it be worth it for THE aliens (the first and only old intergalactic alien race) to hide in this way? I would not naively expect it.

Naively I'd have thought that the shape of the galaxy and its contents would be whatever they wanted it to be, and that attempts to model galactic orbital and/or stellar histories would point the finger at a non-obvious causes, with signs of design intent relative to some plausible economic goal. Like this work but with more attention to engineering intent.

So a good argument against this kind of pessimism seems like it would involve calculation of the costs and benefits of visible projects versus the benefits and costs of widespread consistent use of stealth technology.

If stealth is not worth it, then the Inhibitors (or Weeders or whatever you want to call THE aliens) wouldn't bother with hiding and the lack of evidence of their works would be genuine evidence that they don't exist.

maybe you can do something that breaks the symmetry from the timeless decision theory perspective like send a massive signal to the galaxy...

The pessimistic zoo theory makes this proposal seem heroic to me :-)

The hard part here seems like it would be to figure out if there is anything humans can possibly build in the next few decades (or centuries?) that might continue to send a signal for the next 10 million years (in a way we could have detected in the 1970s) and that will continue to function despite THE alien race's later attempts to turn it off after they kill us because it messes up their stealth policy.

My guess is that the probability of an enduring "existence signal" being successfully constructed and then running for long enough to be detected by many other weed species is actually less than the probability that we might survive, because an enduring signal implies a kind of survival.

By contrast, limited "survival" might happen if samples of earth are taken just prior to a basically successful weeding event...

Greg Bear's "The Forge Of God" and sequel "Anvil of Stars" come to mind here. In those books Bear developed an idea that space warfare might be quite similar to submarine warfare, with silence and passive listening being the fundamental rule, most traps and weapons optimized for anonymous or pseudo-natural deployment, and traceable high energy physical attacks with visibly unnatural sources very much the exception.

As with all commercially viable books, you've got to have hope in there somewhere, so Bear populated the sky with >1 camouflaged god-like space civilizations that arrive here at almost precisely the same time, and one of them saves us in a way that sort of respects our agency but it leaves us making less noise than before. This seems optimistic in a way that Occam would justifiably complain about, even as it makes the story more fun for humans to read...

"If advanced civilizations destroy themselves before becoming space-faring or leaving an imprint on the galaxy, then there is some phenomena that is the cause of this."

Not necessarily something specific. It could be caused by general phenomena.

If we fear the Great Filter, we should not look at risks whose probabilities are high, but risks who's uncertainty is high, where the probability of us making an error is high. 192.168.0.1