Maybe we are late in the universe, perhaps universe used to be a lively and vibrant place homing millions of civilizations. Now, we stand as the last remnants, hence, possibly the most advanced.
Evolutionary biologist here. I think it’s highly unlikely.
It has taken about 4 billion years for intelligent life to have appeared on our planet (if you include the earth forming part), or 3.5 billion years (if you include when life first formed) to get our first “intelligent life.” By intelligent life here, I’m talking about technology in tool using and civilization building, to be clear. It’s a label I’d apply to our many of our ancestral and most closely related species. I believe much of life on earth is intelligent to the point of having things like theory of mind (the knowledge that one is a thinking individual interacting with other thinking individuals), including some birds and octopuses. The birds and octopuses part is important because it means that ToM evolved multiple times independently. That means that a) it’s a “good idea” (it has potentially significant adaptive value) and b) it’s possible to discover it along multiple pathways. Take eyes for example. Last time I looked, we believe eyes have evolved independently at least 24 times. They also exist at every stage of complexity and in a very wide variety of forms, and even something as as simple as being able to tell light from darkness has value.
However, in that 3.5 billion year history, intelligent life evolved exactly once, from a single line of descent. Intelligence such as ours is obviously a good idea. We went from being relatively unremarkable hominids to being the dominant life form on the planet, for better and for worse. Evolution is not moving all species to intelligence. Humans aren’t the point of evolution, any more than sharks or jellyfish are the point of evolution.
When such a manifestly good idea only evolves once, from a single line, the conclusion is that it’s pretty difficult to evolve. It might require a chain of preliminary mutations, or a particular environment. Being hominids, for example, we can make tools and carry fire, which dolphins and octopuses cannot. Of course, there are other hominids out there who do not do those things, and they’ve been around for millions of years. Depending on where you want to start the clock, they’ve been around for about ten times longer than modern humans - about 400k years, give or take. And the technology and civilization part has only been around for the last tenth of that, and has to evolve along its own, non-biological selection - and even those things differ wildly between different places and cultures. And even will all that, it’s become increasingly obvious that this might be a terminal mutation as the very drivers of our short term success may lead to our extinction.
I believe that extra-solar life probably exists. Whether it exists as bacterial mats or multicellular life, whether it’s discovered its own form of photosynthesis or has some other way of gathering life from its environment, whether it draws a distinction between its informational (eg, dna) and physical components - I have ideas but obviously no data.
In any case, that’s why I don’t believe that anyone has ever seen an extraterrestrial-origin ufo. I don’t believe the universe ever was nor will ever be teeming with civilizations.
All of that said, though, we’re dealing with an n of 1. We can make the best inferences possible based on what we can observe, but I would be delighted to be proven wrong tomorrow. I’m a sci fi nerd - I want there to be aliens. Even the discovery of a bacterial mat would revolutionize biology.
Would human intelligence be considered a possible evolutionary dead end? Dumb as a rock dinosaurs reigned for millions of years....modern humans have been her for 10k years and we are in the verge of destroying our planet and eliminating humans as a species.
Awesome comment, thanks for the detail.
To play a bit of Devil’s Advocate (from a bench-top scientific standpoint I come from immunology/microbiology background—so I know enough theory to be dangerous but don’t have your depth of evolutionary understanding) doesn’t a lot of this rely on cosmic timescales? I’m sure I could easily do a web search on this, but I think there are a lot of galaxy clusters that are much older than the Milky Way. That would give the potential for many multitudes of planets that have been around much longer than Earth, which gives a lot of time for intelligence to evolve and sustain. Now, if an intelligent civilization can ever survive for that long is a different question in and of itself.
I personally have wondered if the natural, sustainable, next step in any intelligent evolution is artificial forms of intelligence. Maybe biological intelligence is just the bootloader for less squishy forms of life? Immortal silicon life sort of renders the biological limits of space travel a lot less problematic. I know that comment exceeds the scientific into the philosophical, but it’s a thought I’ve had a lot lately.
I'll add that the sun is a 3rd generation star which are the stars that have planets with lots of heavy atoms like iron and other important to complex chemistry atoms. The sun is thought one of the eariler such stars.
Combine that with it being highly probable that light speed really is the upper limit for the universe. So we are among the first planets likely to be able to support life and and all the others are very far away.
So we are probably among the first batch of life in the galaxy and all the other life is likely very far away. It's not surprising we haven't seen any signs of it even though there is probably a fair amount of it out there.
I’ll also offer that a reason we’ve never seen a real alien UFO is simply the energy requirements limiting speed of travel through the universe (barring some undiscovered loophole in the laws of physics). To go fast takes lots of energy. To carry enough energy to accelerate takes even more energy. We haven’t even gotten to the slowing down part, the power consumption enroute, and recycling everything and replacing losses (atmosphere, parts, the steady and potentially catastrophic rocks and dust that will be encountered at speed, etc) for the duration of the journey. To cross any relatively minor distance would require decades at minimum if you’re in a star-dense area (now you’ve got to deal with radiation issues assuming the alien biology hadn’t worked out to survive that) to centuries.
You could probably get around that by sending robotic AI of some sort which would eliminate needing conventional life supporting systems, but you’d have to wait potentially centuries to get anything back depending on if you hoped to get a signal or a self-replicating ship to return data.
Yeah. Even if there was quite a bit of life the sheer difficulty of crossing distances in space and the energy requirements make it prohibitive.
Intelligence such as ours is obviously a good idea.
Is it though? And does an actual intelligent species destroy it's own habitat and make life harder for future generations? I'd think an intelligent species would do just the opposite. We're not intelligent, we're adaptable and clever.
I kind of close with that thought. A “good idea” in evolutionary biology is one that leads to reproductive success. Obviously, it’s possible to have so much reproductive success that you overrun the carrying capacity of your environment. That doesn’t happen as often when we’re looking at them in their natural environments - because species and environments co-evolve, and so each adaptation has time to be matched by other adaptations.
It’s always tempting to look backward through time and interpret a direct causal development from the bow and arrow to industrial manufacturing and spaceflight. But we can see by looking at all of the different societies and cultures around us that any particular path isn’t dictated by the human brain per se. The Yanomami and the Yoruba are populated with people exactly as intelligent as in any other human society. They are adaptable and clever, but never developed mass manufacturing or rocket technology. There are countless other civilizations that arose, gained a high degree of sophistication and power, and then disappeared while others have survived.
I do not believe in free will. That means I believe in strict causality. If you wanted to argue that the development of modern western political economies are a direct result of the Enlightenment, and the Enlightenment itself was a direct result of the world of ideas that came before it, you’d find a sympathetic ear (although I do believe that determinism is different from predictability, and that this complex system we call our society is more complex than any individual just as a human is more complex and less predictable than an ant).
In any case, it’s possible the “lethal mutation” that might lead to our demise (along with a good swath of the rest of life on earth) might have been a techno-cultural mutation rather than a biological one.
What makes humans more intelligent than an Octopus or an Elephant? Isn't intelligence really hard to measure?
Another question I have is can collective groups of creatures constitute an intelligent body? One example might be a ant colony.
I think these questions are very relevant and collected to computer intelligence.
Those are very good questions. First, I was distinguishing between multiple types of intelligence, rather than ranking them. However, there are several aspects of human intelligence that we’d probably be justified in saying something like “By these metrics, humans are more intelligent than any other species on the planet.” Those include the sophistication of technology, the amount and complexity of of information exchanged between persons, the ability to learn, and so on. Other animals can learn through accident or experimentation and adopt a new behavior. Some even exhibit social learning, as when a troop of baboons learned to wash their food by observing the matriarch, who had discovered it on her own. Most other species have languages, whether vocal, visual, or chemical. But most learning occurs over evolutionary time rather than at the individual level, and most of those languages are fairly hard coded.
The answer is definitely yes for the second question, with the eusocial animals like ants and bees being the obvious examples. The queen is not the “brain” of the colony. She is more like the reproductive organ. The brain emerges from of all the ants collectively interacting with each other and the environment. I agree with EO Wilson that humans are also eusocial, and so by extension carry out collective computation - information processing and learning - at the social level using what we might think of as an emergent brain layered on top of your individual brains.
Has the freeze response to danger evolved multiple times?
Maybe. There are so many possible explanations for the Fermi Paradox.
The Fermi Paradox is an interesting question, but it is not an answer in itself.
The Great Filter makes the most sense to me. The traits that make a species likely to be space faring are the same ones like to cause it to filter themselves out of the future.
This is one of my favorite conundrums about life you touched on above with another comment and this one. Does an advanced society really exist fully "in sync" with their environment? Probably no space program if so, technological progression is slowed to thousands or millions of years (think of only harvesting resources deposited by natural water flows etc). Or do successful lifeforms use up their planets (then solar systems) resources with enough time to get out of dodge?
Every planet and star system will kill their inhabitants sooner or later. Any culture that is gravity bound will surely perish without advances. The "Fermi Paradox" has always been more about threading a needle than a true/false statement for me.
Maybe they're all around us right now, but we can't see/interact with them for some reason.
My favorite hypothesis is we just didn't invent something akin to subspace radio yet. It's like thinking your little remote island is the only populated place in the world because no one responds to your smoke signals, while the rest of the world uses radio.
Or, we could be first.
Someone is/was.
The dark forest theory seems unlikely, since we've been broadcasting our presence for as long as we've been able to, with nothing as a result. I suppose it's possible that they're headed our way now. Or that they don't have FTL so they won't get here for hundreds of years.
A simple counter idea to this can be summarised in one question; Why have we not made an effort to introduce ourselves to ants?
Hey, I introduce myself to ants and other creatures regularly. Most of them ignore me. Of those that don't, either I'm warned off or bummed for food.
I have to believe that we have but that we got no response. Even though ants are very glad for human made structures, and even though we interact with them very regullarly it is hard to say if they are aware of our existence
We do! Ants have been involved in millions of experiments, and that is how we know so much of their society and entomology. We CAN communicate with them using pheromones and food sources. It’s actually quite simple, really. They just don’t have much to say beyond what we observe. It’s not like we suddenly start seeing unique chemical trails so they can communicate with their overlords, so I suppose they don’t perceive us as other beings in the world.
Many children have introduced themselves to ants as a world ending monster. Magnifying glass and sunlight, burning wax, burning rubber, gasoline and fire, Raid... There are lots of ways that children can be the apocalypse for an ant colony.
We haven't figured out how?
I'd think of it like this...
If we make the assumption that we're not exceptional amongst any intelligent lifeforms, then it would make sense to assume that it takes roughly 3-5 billion years for a race to reach where we are now.
That means we could be late to the party, and everyone else has already wiped themselves out, but it's just as likely we're right in the thick of it but just too far away from anyone else in our cohort to see anything, and vice versa.
It's basically just the Fermi Paradox - and the only way we get an answer is when the void answers back.
Didn’t we just get new evidence from JWST+Hubble that the universe may be as much as twice as old as we thought - or ~26bn years?
That relies on the "tired light" hypothesis being correct. It solves a number of problems, in a more elegant way. However, it also requires explanations for some new mismatches. E.g. why the cosmic background radiation doesn't seem to have aged the same way.
It's a theory that can't be immediately dismissed, which makes it interesting, but it's far from proven. Scientists can now look for details that would differ between the 2 models, and so help clarify what is happening.
I wouldn't know anything about that - but it certainly sounds interesting, including what @cynar said
There's also a period of time just as expansion gets going for a few million years where literally everywhere, except the exploding and burning stars, was the correct temperature for water to be liquid. Life may have gotten as far as some basic bacteria chilling everywhere out in "space" which may be why it seems to have been on Mars, back when Mars had an atmosphere and liquid water.
If we know one thing about civilizations, it's that they leave shit around everywhere. If there once were a lot of folk about, there would still be shit for us to see today. We've looked, it seems pretty empty so far.
It would also be unlikely all of them would be dead, most sure, but not all. As far as we can see there is nothing.
We think there is almost certainly forms of life out there, stuff like single cell life. There's probably some of that in our solar system outside of Earth. More complex life would be way more rare, even multicellular would be rare. For a long time Earth was covered in sponges and it might have stopped there. And even if intelligence arises, they might not be tool users. Dolphins are pretty smart, they can't use fire or tools and won't be launching rockets any time soon. But let's say within the span of 100 million years about 10 human level civilizations would arise in our galaxy (which is probably a lot more than reality). What are the chances they get into space in a big way? Most of them would probably live in a gravity well deeper than us. That would make getting into space a lot harder. They might not have the energy budget, will or need to go into space. Their biology might be unsuited for it. But even if they do, getting to low orbit is one thing, getting beyond that is something we haven't even really done in a big way. Getting to other stars seems completely impossible with our current knowledge and no indication we are on a path to ever be able to do that. So say in the span of 100 million years there are two civilizations that live for 1 million years (we've only been around for a fraction of that). They would still most likely not only be thousands of light years apart, they would also be seperated by millions of years. And that's with some super optimistic assumptions.
So no, there is nobody out there.
There's a saying in the astronomy circles. Things happen either once, an infinite number of times, or never.
So all our evidence about life is from a sample of 1: 1 planet and it's development. Everything else is extrapolated from that. We don't know what rates of evolution should be or could be.
Also in terms of civilizations leaving junk everywhere, that is potentially true. But we also only have a sample of 1: 1 planet and 1 solar system which we have barely scratched the surface of.
The absence of evidence is not evidence in itself. We will have to go out in to the universe to see what is there.
In terms of travel to other systems - in theory self replicating ships could spread across the galaxy to every system in about 500 thousand years at sublight speed. Space travel is not doable in a humans life time, but it is doable on the scale of a stable civilizations efforts to spread into the galaxy.
There are also theoretical ways to travel faster than life. Whether they are pure fantasy or potential science only time will tell. We still can't even detect much of the universe, let alone begin to manipulate it.
We simply know too little to know what is going on in the galaxy. To say "there is nobody out there" is just a possibility, not a certainty.
Aka, The Fermi Paradox
Not likely. Based on the amount of known matter, ratios of detected elements in various locations, and life cycles of stars, we're most likely pretty early on the scene. As just one example out of many, phosphorus (which is needed for life as we know it) is kinda rare in the universe and our little piece of the galaxy is unusually abundant in it, especially Earth.
Yeah, it's called... umm... I forget
Alright good talk
Haven't had that thought, but the total opposite. What if it's hella early, and we're still the most advanced lifeform in the universe? We're over here writing stories and making movies and games about aliens more powerful and technologically advanced coming here and fucking us up, when in reality we are the advanced aliens and everyone else in the universe is either barely sentient or still cavemen in terms of evolution and technological awareness.
I think this is more likely, and it's probably millions of years gap.
This is one of the speculations among many in the great filter hypothesis.
I think it's more likely that we are early, possibly the first. If we survive, we will have millions of years head start to other species. Imagine how huge of an advantage that will be.
By then we’ll have iphone 20s and GPT-10!
There are 200 billion to 2 trillion galaxies, and in the Milky Way alone we have located at least 10 planets in the Goldilocks zone. That could mean at least 2 to 20 trillion Goldilocks planets, and this is an under-estimate because the scale of our search has been comparatively small. So it is likely that there actively exists plenty of tool-using, scientific, space-faring life forms out there as you read this.
As for time scales, the heat death of the universe is estimated to occur in 1.7x10^106 (or, written out, 17000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) years. Many, many planets will move into or out of Goldilocks zones in that time. And, depending on the source and the age of the information, we estimate the age of the universe to be 13 or 26 billion (or, 26,000,000,000) years. I added zeros so the two numbers could be visually compared, and you can see we are a very young universe.
Combine these two points and you have ample time and opportunity for many, many civilizations to rise and fall. Where ten planets’ stars may be exploding, ten more may be just entering the prime conditions for life. So take comfort in the thought that we are, statistically speaking, not alone out here.
Have you seen the Fermi equation? Habitable planets aren't the only variable.
What part of swiftcasty's comment gave you the impression that they aren't extremely familiar with Fermi's work?
We don't really know anything about life in the universe. As for life in our galaxy, its entirely plausible that we are early.
Nonsense about being the most advanced
We're actually quite early into the age of the universe.its possible that every civilization is at similar technology levels currently.
So what you are saying is Great Filters exist and we are doomed no matter what we do?
The universe is too young for that to be likely.
Yup, all the evidence scientists point to agree that if anything we are early to the party.
It's wild to think that we may be what aliens call "the elder races" or "precursors" or something like that, depending on if we survive that long.
The observable universe is too young for that to be likely
The difference is vast probably beyond anything we can imagine.
Given that we can see the CMB it seems unlikely that the universe is older elsewhere.
No but we can estimate the total age before cosmic inflation renders the universe cold and so far spread out so as to be considered “dead”
That timeline is around 1027 years, of which we only right now have been around for about 109. So we are VERY young compared to the max age. On the cosmological timescale, we are still “being born”