Dinosaurs were around without evolving into braniacs for 200 million years. Why would another 65 make the difference? Why did mammals get smart in only around 63 million years?
Ok, and I disagreed for the reasons given. Do you have a response to those reasons?
Sorry, I didn’t get right what you were saying before now, I’m going back to recheck and respond correctly.
Yeah no worries I didn’t mean to bully anyone.
How many advanced civilizations do you believe inhabit our galaxy?
I said I believe life may be common in our galaxy, but I didn’t mean so common as to be present in any star system in our general (observable) vicinity. Abiogenesis, as far as we know, occurred just once on our planet. Sure, once it occurred, life evolved, branched, flourished and filled every habitable environment on Earth.
I don’t believe the transition from simple to complex life is a great filter ( life finds a way</Jurassic Park>). But, it needed to start before flourishing. And complex life doesn’t necessarily include super-intelligent life. Emergence of intelligent life from multi-cellular life should be treated as a separate filter.
IMO, the big filter is abiogenesis. Abiogenesis is improbable.
Abiogenesis of course factors heavily into the Drake equation. While strides have been made in calculating the probability of organic material emerging from inorganic material in a lab, scientists remain unsure how accurately this factors on planetary scales. This article explains the situation.
I personally believe the probability of abiogenesis, even on planetary scales, is extremely rare. When I say I believe simple life is “common” in the galaxy, I’m thinking downwards of perhaps 10,000 cases in a galaxy with 1011 Sun-like stars, like the Milky Way.
How many of these hypothetical 10,000 life-bearing planets have evolved advanced, interstellar traveling civilizations? Hard to say, but I think “a handful” is a reasonable number.
Therefore, I don’t believe accounting for “every alien civilization” is a large number at all. I think the number is quite small (~ a handful). In that perspective, positing “all advanced civilizations are likely to have evolved past the archaic human mindset of unlimited expansion and venturing beyond the controllable horizon” is not a tall order, because there’ are not many (or any) in our galaxy to buck the enlightened trend. Millions? Yes, probably a few trend buckers, and we should see evidence of their existence. A handful? Probably not.
Back to the question of why an AC would send self-replicating probes to far reaches of the galaxy when it would take a minimum of tens of thousands of years to reap any benefit, I still don’t believe they would bother. Even we colonizing, expansion-hungry humans don’t plan that far into the future. A few generations into the future, sure. Let’s do something nice for our grandkids. Thousands of generations? Humbug, we’ll leave that problem for our distant descendants.
So, I don’t believe we’re dealing with a Star Wars galaxy, with spaceships manned with a plethora of various alien species zipping all around interstellar space. I think we’re dealing with a few ACs, if we’re lucky. And, I don’t believe it’s unreasonable to believe all of them have eschewed the desire to expand into far-away places beyond manageable central control.
Nutshell: Abiogenesis is the big filter. It’s extremely rare. The few advanced civilizations that have likely emerged in our galaxy have evolved past the archaic notion of expanding into every nook and cranny. That’s why we don’t see evidence of life beyond Earth. That’s my perspective anyway.
We don’t know this for a fact. Abiogenesis could have occurred multiple times, but our ancestor won out and consumed all other forms of life. Hell, abiogenesis could be happening ALL THE TIME today, but every time a nifty new configuration of self-propagating proteins assembles itself, it promptly gets eaten by neighboring life.
Or, it is even possible that abiogenesis succeeded multiple times. We don’t know for sure if the earliest celled life evolved from the same sort of thing a virus is, or even whether viruses predate life or require it to exist.
That’s why I said "as far as we know." But, my guess, given the improbabily factors, is that it occured once on Earth.
Looking at it a different way, if abiogenesis did occur multiple times on Earth, then we would expect to see evidence of life on the next Goldilocks planet over. But, so far, we don’t.
How much looking have we actually done? Not much, though the JWST is just getting online so that may change soon.
We only discovered Proxima Centauri B in 2016 and don’t know if it has an atmpsphere yet, much less whether or not it is lifebearing.
JWST may very well tell us that there are biosignatures like oxygen or methane in the atmospheres of nearby worlds.
Anyways, I’m not arguing that abiogenesis necessarily did occur multiple times. Just that we don’t know. And it’s very possible that it DID occur only once because once life was running around eating nutrients the conditions that allow abiogenesis to occur were destroyed.
And if they tell us that tomorrow I will happily eat my words. Frankly, I’m growing tired of Earthlings and very much want us to not be the only game in town.
The existence of life would probably make abiogenesis less likely to occur again though. They would likely be breaking down some of the materials needed to come together to make a protocell. And then those protocell would need to somehow compete with cells that already have a number of useful mutations.
Abiogenesis happening once in itself doesn’t say much about its probability.
Personally I’d still lean towards multicellular life being the bigger hurdle, just based on the apparent timeframe on earth. But who knows, perhaps it was the former.
But it’s really accounting for every single individual, and for millions of years.
Launching a self replicating probe requires very little resources. To a species with easy access to space, and able to mine asteroids, it would probably be cheaper for Kang and Kodos to launch a self replicating probe than for you to throw a message in a bottle into the sea.
Right, the fact that abiogenesis on Earth seems to have occurred as soon as it was possible for life to exist on the planet backs up the idea that abiogenesis isn’t going to be very rare.
Not to be simplistic or state the obvious, but if advanced civilizations as a matter of course launched unrestricted self-replicating probes into the galaxy at large, and their existence coincides with our time-frame, then we should see evidence of them. I’m giving a plausible reason why we don’t see that evidence without resorting to the Debby Downer conclusion that they don’t exist.
That’s the point. We contend that given how easy and quick (relative to stellar or evolutionary timeframes) colonizing the galaxy is, even for an individual or marginalized subfaction within an advanced civilization, the only reasonable conclusion is that advanced aliens do not exist at this time.
Whether that is a debbie downer conclusion or not is irrelevant for determining if the evidence supports it or not.
“Not existing” is certainly one explanation. I just happen to believe there are other valid reasons why advanced civilizations may not want to launch unrestricted probes, or attempt to colonize the galaxy.
The whole point of the Fermi Paradox is that none of the reasons people have brought up would apply to every individual of every species, and so just aren’t convincing.
Isn’t it possible, or even probable that advanced civilizations have evolved to cooperate with their own species to the point that there are no rogue individuals who go against the grain of central command? We’re not talking about the human collective consciousness here, we’re talking about something better and more evolved.
One good reason for this is that we haven’t really seen any Goldilocks planets yet. Thousands of planets have been found, but none are particularly similar to Earth, and most are completely inhospitable to life. Add the rarity of Earth analogs to the unknown frequency of abiogenesis, and the ‘rare civilisation’ hypothesis looks more likely.
Possible, sure. Probable, I don’t think we have nearly enough info to determine. But to be a Fermi Pardox solution, “probable” isn’t enough. We’d need every individual of every alien race to act this way. Do you think it’s likely that this path isn’t just probable but inevitable?
Can any individual of any advanced alien race launch intragalactic probes all by himself? Don’t you think the will of central command would have safeguards against rouge individuals?