It is kooky to believe there if definitely intelligent life elsewhere in the universe, as is believing there definitely is not. Most of the space between those two concepts is rational to consider.
More and more, I believe that the best evidence for intelligent life elsewhere in the universe is that it has studiously avoided having anything to do with us.
It is sad, isn’t it.
All indications are that earth was this close to making a sentient and relatively peaceful Hominid a couple times.
And probably other Families were not that far behind, on geological timescales.
But “Homo sapiass” ended up winning the race. 
Humans are relatively peaceful; we fight much less among ourselves than most animals. Most people can go for literally decades without violence.
It’s just that we’re really organized and really good at killing when we do fight. We’re exceptionally lethal, not exceptionally violent.
That’s more to do with civilization: societies have reasons to discourage and prevent violence, and humans of course have the ability to learn. Anthropologists estimate the murder rate in ancient societies was around 50 times the rate in modern societies.
And, as I say, the data also implies that our closest primate relatives do not / did not share this level of aggression, apart from chimps.
Of course none of this means we can’t become an interstellar species or whatever, some day.
I was just sharing @jackmannii 's lament about us as a species. If we didn’t have wars, if we didn’t organize into tribes that try to work against each other, we’d probably already be an interstellar species.
I like this turn of phrase.
Speaking of mass lethality, perhaps it’s simply impossible for a plural civilization to become interstellar. At some point, perhaps one person or faction’s capability for destruction is too great in the name of efficiency.
There is one potential solution: Before that timebomb blows up, a species, could somehow evolve into some sort of hivemind, with all the brain power but none of the species-destructive free will, to prevent nihilistic or warring factions from destroying planets or habitats while still efficiently managing stellar levels of power.
The drawback is that there is no way to know how the hivemind will feel once it is born. What if it’s super lonely? If the hivemind itself decides to commit suicide one day, the entire species goes extinct, which is much more definitive and permanent than a “simple” civilizational collapse.
More specifically, if we didn’t have a very, very, very, very, very, very, very small number
of very, very, very, very, very, very, very arrogant selfish greedy hypocrites who stir people
up to have wars and organize into tribes that try to work against each other…
That’s part of the problem.
The other problem is that we have a shitload of people on whom those tactics work. If everybody just laughed at would-be strongmen, they wouldn’t matter – they might manage to kill a few people off out of frustration before being stopped, but they’d never get wars going, or entire societies set up to temporarily benefit themselves while damaging others.
If we didn’t kill each other so often something else would have to prevent us from overpopulating and exhausting necessary resources even faster than we have already.
Readily available birth control might do that.
But of course for most of our evolution we didn’t have that option. I have wondered before whether we kill ourselves for the same reason that lions do: not much of anything else can, and something needs to. (I strongly prefer the birth control option. Evidence seems to show that there’s no need to make it mandatory, just make it available and acceptable: the people who really want to have lots of kids will be balanced out, maybe more than balanced out, by the people who want none or one or even two exactly.)
– I’ll also note that our current methods for killing each other also exhaust resources at quite a high rate; so this technique is, to put it mildly, no longer working. Unfortunately evolution can take some time to correct for cases in which something’s no longer working, and sometimes does so, when it gets around to it, by ending the species.
It’s 2024. It’s time.
Time for the world’s first carbon-neutral genocide!
There must be some answer to the fermi paradox that says that at some point, all conscious species realize how cold the universe is and stop reproducing, thus willingly going extinct. Maybe that’s the path Earth is on now? The numbers certainly do not immediately rule it out since wealthier nations with greater access to birth control and great social acceptance of childless couples have lower birthrates and going down, with South Korea in the lead.
I suppose that’s one answer to it. But it also seems to me that conscious species may realize how large the universe is, decide their local hospitable area is becoming crowded and anywhere else is implausibly far to try to reach, and aim for relatively stable populations.
The argument that there would only need to be one spacefaring species that came to different conclusions is a fair one. But it’s possible that those different conclusions are just wrong – that the distances are too far to be practical, the imagined technologies are not just around the corner but only just around the imagination, and that species that decide that instead of controlling their population they’ll just keep expanding somehow forever are the ones that don’t make it.
There is a very simple answer to the Fermi Paradox. There are no other intelligent, technological, space faring others, at all. Anywhere in the Milky Way home galaxy.
None. Anywhere. That is what we have evidence of, no one. No evidence of them is science, speculation and probabilites is not.
The answer to the Fermi Paradox is that there is no one else.
The answer to the so called paradox is that space is huge, not only bigger than we imagine, but bigger than we can imagine.
Even if there was intelligence life in OUR Galaxy, it could easily be 50000 light years away. let say they are at our level- we wouldnt know about it until 50000 years had passed.
The Universe is almost 100 BILLION light years across. There could be millions of intelligent lifeforms- and we would never know.
And yet, 50000 years is a small slice of time in the life of our galaxy.
If a civilization, bent on exploration and exploitation of the galaxy, was able to spread at 0.01c from the outermost arm of the galaxy, it would take 10 million years to spread throughout the whole galaxy - less than 1/1000th of the time our galaxy has been in existence.*
So if there was one civilization, with that 0.01c propulsion tech level, that got a 10-million year head start on us, we should be seeing their colonies right in our neighborhood, if not right in our solar system or right on our planet.
Hence Fermi’s question, “Where are they?”
So something must be happening to keep what civilization has existed from achieving that level of tech, from wanting to expand (or just not wanting to pay the price tag involved), from wanting anything in our galactic neighborhood - something.
But just distance isn’t the issue, not if some civilization got a 10 million year head start on us. I tend to go with the @Dallas_Jones explanation, myself - intelligent life is really, really rare - but given the time frames involved, distance can be overcome, at least with some level of determination.
* Numbers from Google and Monty Python’s “Galaxy Song” - but probably pretty close on an order-of-magnitude basis.
Why would we think they are either interested in us or use a system we can easily detect?
Why? Maybe they never wanted to expand beyond their system? Maybe they got technophobes in charge, like is happening here.
How long has our galaxy been in existence now and when did we first send something into space? Isn’t that only a few years less than 1/1th of the time our galaxy has been in existence?
And about thirty times the length of time that our species has been in existence. Let alone any particular civilization in it.
Why do you presume that any civilization would remain the same civilization, using similar tech and behaving in similar fashion, for 10 million years, even if not also spread over 100,000 light years?