- cross-posted to:
- space@lemmy.world
- cross-posted to:
- space@lemmy.world
A public lecture from a scientist adding to the conversation. What makes this lecture interesting is he is not disproving that alien life can exist, but instead trying to curb expectations because of the little data we have to back up claims. More importantly is the message that it is important for scientists to be care of biases when discussing this topic.
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Theoretical biologist here. I haven’t looked this person up, but from the talk I’m going to assume he’s teaching an astronomy-related course. He does mention biology but I might be able to go into more detail.
I am also very skeptical about intelligent life existing in the universe. I’m certainly not saying it’s been proven false - of course it hasn’t - but from some of these responses I can’t tell if anyone has actually watched the video. I ran through it at 2x speed - it’s not technical at all - and I highly suggest watching it like that if you’re feeling like the title misrepresents factual observations. I’m not going to address the questions about astronomy, because I think the lecture covers those adequately.
First, let me say that I think it is entirely plausible that something that we could in theory come to recognize as life exists elsewhere. Please note that I am choosing my words very carefully. There is a discipline called exobiology that tries to understand what life actually is, what chemistries are compatible with the complexities we associate with living processes, and how evolutionary dynamics might affect them over time. We think that there needs to be an informational aspect as well as a physical-physiological aspect. The former provides the basis for replication and evolution, while the latter maintains integrity and what Schrödinger called “negative entropy” associated with living systems. It doesn’t have to be DNA, it doesn’t have to be in chromosomes. It will probably have to have something like a cell. It will probably need water. Other than that, I think I’m pretty open to ideas.
Complex life, and in particular life exhibiting technological intelligence (which is how most of us think of intelligent life) is a much higher hurdle. Earth - our single example - has been fairly teeming with life for around 3.5 billion years, give or take. It is evolutionarily highly dynamic (for whatever that means when your sample size is 1) with both mutation and recombination playing roles in genetic and phenotypic diversity. The sheer diversity of factors - transcription, regulation, editing, and so on all provide targets for evolution. Complexity builds upon complexity.
And, given all of that, there has been exactly one single line that has led to technological intelligence. It evolved once. And the thing of it is that, evolutionarily, it’s a really good idea - so much as to allow humans to drive themselves and wide swaths of the entire global ecosystem to the border of extinction. When good ideas occur, they tend to evolve early and often. Eyes are a great example. It’s a very good idea to be able to perceive light, and at my last count I believe eyes have evolved independently around 24 times.
If intelligence evolved once - and we’re not talking about dolphins or dogs here - despite the fact that it allowed humans to almost instantly become the apex species on the planet - that tells us it’s very hard to discover from an evolutionary point of view.
Long story (not so) short, I think it’s unlikely that humans will ever encounter an extraterrestrial technological intelligence. I think that, if we should survive the next century or two, we could likely find the equivalent of bacterial mats. This would be hugely exciting for biologists and would (in a very very literal sense) change life as we know it. We’re just not going to find big headed bug eyed aliens in flying saucers or Vulcans.
First, I want to fully admit I didn’t watch the video. Apologies ahead of time if that causes me to be redundant or reductive.
Second, I’m also a biologist, although a molecular one.
Third, I agree with almost all of your premise and train of thought. We’re certainly more likely to get the likes of “bacterial mats” than intelligent life anywhere, and especially within a distance that we will ever realistically encounter.
I do wonder, though, how you (or maybe the video guy, but obviously not enough to watch the source material before making an ass of myself…) conceptually reconcile the small sample number of known planets with life (n=1) with the mindblowingly impossible number of worlds.
You say that intelligent life evolving only once indicates that it is difficult for evolution to “discover”, which is surely possible to be true. But given that we haven’t seen the evolutionary conditions on other hypothetical worlds, from what we know, the evolution of intelligent life has a perfect 100% success rate of occurring on planets with life.
In fact, you mention the independent convergent evolution of eyes as an indication that eyes are a “good idea”, and that they must be relatively easy for evolution to discover if they evolve independently, repeatedly. But evolution is subject to the whims of selective forces, so a different world would surely select for different traits. Eyes (or other extremely common evolutionary pathways… looking at you, crab body) might be less frequently selected for or be entirely useless, but intellegent decision making and tool use might evolve in ways we can’t even conceptualize in our context.
This also extends to the claim of how our world is evolutionarily dynamic (which you point out is hard to quantify in context). We don’t know the dynamics of evolution on other worlds, if it happens at all. Recombination could be a unique characteristic of DNA-based life on Earth or it could be extremely common. Other worlds might have longer or shorter evolutionary time lines, also, since our sun’s “working life” is shorter than average due to its size and density. Without another example for reference, we don’t know whether we’re evolving quickly and with diversity or slowly and conservatively.
I guess, I don’t think you are wrong, exactly. I just think you are necessarily making assumptions based on how things work here in order to extrapolate how things might work there– one has to! But the whole discussion (which continues, like this, to this day) revolves around just too many unknowns. We just don’t know, and can’t know.
Climbing down from my high-horse, though, I have to admit I’m biased, since I have a pet-belief that life is basically guaranteed to exist elsewhere (how freakish would it be for it to only happen once out of so, so many chances?). I honestly feel like there’s a good shot that it’s incredibly common, at least in a basic form. In essence, I suspect that if we find bacterial mats (or soup) on Enceladus or Europa then it’s basically certain that life is everywhere. But we won’t even likely know that in my lifetime, so… I keep dreaming!
Given the size of the universe, asserting that we’re the only intelligent life in it is a ridiculous stance.
We don’t need to be the only one period in order to be “alone”, we just need to be the only one within a particular large region. If the probability of intelligence arising is low enough then that’s not unreasonable.
This is one of the first things addressed in the lecture.
And he discredits his own argument 20 minutes later.
Maybe we’re the only 3 dimensional beings.
He spent 25 minutes contradicting himself and concluded “we don’t know”.
First off; This is a highly engaging lecture. I’d encourage folks to withhold comment before watching it through.
Second; I’m failing to find the syntax to call out other users. I’ll go caveman style and reply to the 2 posters I wish to engage with permalinks. Could you reply to this post instead of the post I ping you with?
Have you read any of the Deathworlders universe? Fascinating take on science fiction tropes, turns many upside down. I’d like your take! (Free to download, but don’t read the main page, all spoilers. Give the first chapter a read for taste.)
The premise is that the Milky Way has several intelligent sophonts. Twist being, humans are the only intelligent life that evolved on a “deathworld”, not possible in the minds of the aliens. Planets like Earth are regarded as totally inhospitable to intelligent life. Factors like gravity, solar radiation, viruses, bacteria, fungi, parasites, predators, plate tectonics, violent atmospheric phenomena, temperature extremes, all that, are just too brutal for evolution to produce intelligence. Intelligences that evolved on “softer” worlds are the norm.
I’d argue that some of those items, such as radiation, are necessary for complex evolution. Arguably, some items like parasites are inevitable byproducts of any evolution.
I so loved reading you two kick evolution around, and I so wish you would give a thought to the “deathworld” notion.
