I think at the scale of the universe life even thinking capabilities life is almost certainly inevitable.
What's not inevitable is that it can thrive, and survive to a galactic scale. That's not even yet certain for us.
Universe is too big, we're all too far apart. Civilizations come, civilizations go. Some may not be on a planet where even rocket travel may be possible - no source of energy dense enough. Some can get wiped out by disasters. Asteroids. It's happened on this planet a bunch of times.
It's like the Birthday paradox. It's likely 2 people have the same birthday. It's not likely that someone else has YOUR birthday.
1 in 10 billion trillion is some pretty serious odds.
It does get more complicated if we factor in life happening quickly enough without an extinction event.
But after looking at images like this there is just NO WAY we are the only ones.
What I'm more pessimistic about is how long such intelligence might live. How many civilizations reached a point of harnessing nuclear power and then wiped themselves out with nuclear war?
It is pitch dark. Could one raindrop survive long enough to at least hear the sound of another landing before it disintegrates?
Is the time between the drop striking the plane and the drop smashing apart so short that no drop ever hears another, or even sees evidence that any drop other than itself ever existed?
If it is a machine that can reproduce itself, growth, collect energy, use energy, do actions based on events, etc, then animals match this profile (perhaps even plants), and also, at some point computer will probably reach that goal.
Despite that, computers won't have a "soul", so where this soul comes from is a big mystery.
I'm not even sure that two humans can prove with certainty that the other ones has a soul, this is still an unsolved problem.
Something that involves "thinking capabilities" in a form we would recognise?
That's always what I consider when someone mentions the Fermi Paradox.
Humans tend to barely recognise "thinking capabilities" in other mammals. There is intriguing evidence that plants "communicate" and "remember", and have been doing so around us for at least as long as mammals have existed with humans barely noticing and usually ignoring or criticising researchers who suggest that perhaps plants may be "thinking".
https://www.botanicalmind.online/podcasts/plant-sentience-a-...
If we don't even recognise "thinking capabilities" in the plants that have been around us for as long as we've been around as a species, what're the chances that we would notice and recognise "conclusive evidence of advanced extraterrestrial life" when we saw it?
Suddenly 1 in 10 billion trillion odds doesn't seem so (and I apologise in advance for this) astronomical...
/pedant
Think about other earth-centric scenarios, and try and imagine if dolphins or octopuses or fungus or maybe even insect colonies or plant ecosystems had "won" and become the apex lifeforms on earth instead of humans. I wonder just how different concerns like "civilisations" and "war" and "nuclear power" would have played out in those cases? I wonder if assumptions like "industrial revolutions" and the inevitability of scientific discovery being used in detrimental ways like we have done with nuclear science actually correlate with "intelligence"?
I think the odds are that at least one of them does.
Like they say, the first million is the hardest.
If you ever study evolution on the other hand, you would realize how fantastical these assumptions all are. No, life elsewhere if anything is far more likely to look like how it did for most of the history of life on earth: unicellular. People forget that even multicellularity, let alone an organism with an entire bodyplan, emerged from pure chance, and could have easily been wiped out or outcompeted for resources as soon as it came if it didn’t have sufficient fitness. How lucky it was for us that our ancient eukaryotic ancestors enveloped that first mitochondria. How different life would look today if that never happened and we never had such an energy source to actually support these later iterations, considering all life that exists today are directly descended from this single line. How supremely unlikely it all is to tread even close to the same path. How many potential paths are lost along the way and how many paths only emerged as a result of previous paths.
That’s about 100^5, so one way to think of this is that if you categories these by any four properties (temperature, stability, hydration, day length) then you’d expect about 100 samples for any point in that 4D space.
So even if you believe Earth is unique along four critical metrics, there are about a hundred planets per galaxy that also have those attributes within a percentage point. If you allow some wiggle room then you have tens of thousands or even millions.
We know conditions here on Earth varied significantly more than 1% over billions of years and life survived and even thrived.
Sure, maybe that’s a requirement for the type of life we on earth know about, but I don’t see why other elements couldn’t have also formed in just the right way to be able to reproduce, and maybe eventually “think”.
Assuming the cosmological principle is true and the universe is infinite, wouldn’t we be guaranteed an infinite number of Sols? ;)
It's just too arrogant to think we currently can place odds on all the important events necessary for us or something like us to come into being. At the time this equation was devised, I'm not even sure they understood how crazy lucky the development of mitochondria was.
In reality, we just don't know the many factors that might've affected our outcome. Also, it's just pure lottery falacy to reason about the statics that specifically "we" exist. If the odds for some strange reason settled out around about 1 of there being a single sentient species in our universe, that species would come to reason about itself and produce the same long odds of their existence. It's a longshot that a specific someone wins the lottery twice. It is a statistical inevitability that someone will win twice.
Whoever they are, they can't alienate themselves from being the one despite all the statistical huffing and puffing they can conjure. We will only know how special we are when we find another or once we have surveyed enough planets in depth.
Looking at other forms of chemistry we don't see much as naturally varying as carbon. Though I have heard some chemists and biologists hypothesize about sikicon based life. At high temperatures it forms the kinds of dynamic connections that carbon does.
Maybe these species are distributed evenly throughout our 90-billion-lightyear-in-diameter universe.
Maybe half evolved to our current level of sophistication in less time than it took us.
So... what is the minimum duration of time, after the big bang, that some lineage of creatures might take to evolve from sludge into a life form capable of emitting data via radio waves? It cannot happen instantaneously... first conditions need to cool down enough to be amenable. Beyond that, it seems to require a little time for evolution to get to human-like level, it took us 13+ billion years.
So given the lack of meaningful signals we have detected so far, Occam's Razor says the nearest intelligent life that currently exists out there is too young and far away for its transmissions to have yet reached Earth.
But I won't go to the mat arguing my impression; we only have evidence from one planet to go by, so any view here lacks empirical evidence.
Also, Captain Archer in Enterprise used the name Sol when making contact with aliens.
Yes, climate change is a massive problem, and humanity is ignoring it to our own peril.
But peril here means the unnecessary deaths and displacement of hundreds of millions of people - a civilization-defining tragedy no doubt, but ultimately nothing so serious as to cause our extinction.
We have the technology and knowledge to adapt, change course, finally get of fossil fuels, and enter into a new age of sustainable renewable energy.
We're gonna do it too late, and whole ecosystems, species, and far too many humans are all going to perish. Sea life may become extinct.
But at no point is our survival as a SPECIES in question.
If we become a space-faring civilization, how long will it take us to colonize the galaxy, such that there are few places you can go and not find evidence of humans around? Not more than a million years or so.
So if intelligent life -- capable of becoming a space-faring civilization -- is common, why is the galaxy not colonized already?
Kursgesagt has a good video on this: https://www.youtube.com/watch?v=UjtOGPJ0URM
Perhaps instead it is to be observed in energy preserving vessels (i.e. emit nothing) in transit to the next fuel stop (a planetary system). Perhaps dark matter can be explained by the congested highway of these unobservable vessels.
There's still doubt:
https://en.wikipedia.org/wiki/Drake_equation#Range_of_result...
To prove, we would need to find such life.
To not have doubt, we need to have a reasonably high confidence that such life is there. However, the estimates are so wild and range from very unlikely to no-doubt. Thus, there is doubt (to the best we understand).
The Milky Way is 100,000 light-years across. So at least that long assuming we can ever attain near-light-speed travel (unlikely). And due to cosmic inflation, many other galaxies are receeding at faster than light speed, so we could never get there.
There could be a lot of intelligent life (as intelligent as us, maybe more so) that can never realistically travel beyond their local star systems, and we'd never notice them.
Sure, it's easy to imagine someone doing it a million years faster than us. But at the same time it's very likely we are just early to the party.
In PIE it's sunnōn. In some languages that evolved to some variation of sun or son, in some to became sol (notably Latin). And many use both variations in some capacity
If the calculations were to say there's very high chances of the universe teeming with life at many places, but life is not 'found' yet, then I would say it like 'no proof but no doubt'.
E.g.: You might believe that some variability in conditions (hot-house Earth, iceball Earth) is required to "kick start" evolution. Okay, then simply pick out the subset of the parameter space with that amount of variability.
But I don't think we will find it. Life is special. The earth is special. And all the planets and all the stars and all the solar systems and all the galaxies cannot make something special again. So alas, we are earth. and we are all that is out there. And the rest of the universe is just there for our awe. That is how special we are.
What we do know that we don’t know, is already a massive amount - enough to not have any actual confidence in any guesses we could make.
Hell, Europa could have life in it, and we currently couldn’t tell. Venus too. Maybe Mars. Maybe IO.
Multicellular life is certainly less common, and sapience is also less common (and may not be only an emergent property of multicellular life) than just replicating chemical structures.
Certain pushes in Earth's history likely shaped and sculpted current state, but the general factors aren't terribly uncommon (water, Goldilocks zone, somewhat stable solar systems, etc.). Moons at our size are less common, and whether that is crucial is unknown. Snowball earth and hell-phase may be common. Plate tectonics may be a limiting factor.
I look forward to humanity discovering this, then finally agreeing that perpetuation of sapience generally or humanity specifically beyond the heat death of the universe is a good goal, much better than the common banal drivel that drives our wars or religions today.
If you are looking for a goal, then you are looking for a fight or a war.
Instead, a good goal is what comes from the good lessons of religions: the idea that humanity is nothing, that you are nothing, that your plans are nothing, and all that matters is the creator and the rewards he set abound around the problems that you struggle against. Lessons like good vs evil are derived from this paradigm. And the paradigm also inspires studying the universe from obsession with the creator's enigma.
OTOH all ideas that lead to war and conflict grow from obsession with the self. If not the self, then with your people, and if not the people then with your hatred for anyone other than your self and your people.