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Comment by Razengan | Hacker News Reader

The Fermi "Paradox" is based on so many naive self-referencing assumptions it's ridiculous that it's considered so seriously so often.

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I don't even understand why people call it a paradox. A paradox has no obvious solution. This one has many obvious solutions, the most obvious one that the premise is faulty: perhaps life is not common at all.

That's part of the Great Filter answer to the Fermi paradox. Though, I agree, it's not really a paradox. If the great filter is true, the first filter is life forming at all. We hope that the filter is behind us and that's why intelligent life in the universe seems rare, rather than ahead of us. If life is common, but intelligent life is uncommon, that's concerning because it makes it more likely that the filter is ahead of us. Meaning, something like, once an organism has control over the whole planet there's something that prevents them from going to multiple planets.

There is another premise that is faulty: that the answer to "where's everybody" is that "since we see nobody, there is nobody". But for all we know the planets around Alpha Centauri may be teaming with life, and there would be no way for us to detect that. If only 1% of the solar systems in our galaxy host intelligent life, then the number of intelligent life forms would be truly mind-boggling, yet we wouldn't be able to detect a whisper of their presence. For the simple reason that space is also mind-blowingly vast, and all signals decay with the square root of the distance.

I mean, we don't have any other perspective to look through. There is no other point of reference to draw from. We try to compensate by assuming that our system, planet, and species aren't particularly special and are probably about average in terms of supporting life.

We can't know or even begin to guess at what an alien civilization may do or think or how they evolved. Best we can do is assume it's probably somewhat similar to our experience. At least it's based on something factual. Anything else is really just wild speculation.

We pretty much have to assume aliens will be sort of similar to us because we haven't met any. Our experience is the only one we've got, so it's the most reasonable baseline we have. We know that aliens will probably be wildly different from us, but it's so unknowable as to be moot. Do we base our assumptions on Heinlein's writing? Asimov? Douglas Adams? Anything other than what we know from our own experience is just fanciful fiction.

But also you're not supposed to take as read the Fermi paradox, Kardashev scale, or any other ways of thinking about aliens. It's implied that they won't be anything like us. You're not supposed to take it as a literal statement that alien species will be hairless bipeds with a warlike society who think and look like us. You're supposed to follow the assumptions that statistically, we're probably not special as a species and probably any aliens we meet will have evolved along similar lines and probably will be relatable to us. Implicitly we understand that this likely is not true. We just don't know and there aren't really any options that are more reasonable or reliable than basing assumptions on the one and only planet we know that has intelligent life.

This is too pessimistic. We can absolutely "begin to guess" at what an alien civilization might look like or how they might have evolved. Reasonable possibilities are very heavily constrained by information theory, the laws of thermodynamics, the very finite number of elements that make up the universe, chemistry, particle physics, etc. You can appeal to fantasy by dreaming up multi-dimensional energy beings, and of course such things have some tiny but nonzero probability of existing. But you can do the same thing regarding what we might find if we look at some random pond water under a microscope. Maybe we'll find crazy silicon-based life forms, or some phylum we never knew existed, or a microscopic Tyrannosaurus Rex! Maybe. But it's perfectly reasonable to ascribe an extremely small probability to such things based on everything we already know about the universe, and it's reasonable for the same reason to ascribe a very small probability to the existence multi-dimensional energy beings that would completely defy our understanding. For any given alien life form we might find, there's a very high probability (I give it at least 90%) that it would be based on chemical pathways that would make us go "oh, neat", but not go "THIS CHANGES EVERYTHING!"

I'm a complete layman, but I wonder if chemistry on Earth (and rest of our solar system) is also influenced somewhat by the particular properties of our star, its and our magnetospheres etc. and the gas clouds our planets coalesced from.

As in, different stars may encourage slightly different chemical reactions and interactions on their planets.

Like, for example, could it be possible for a planet to form with a naturally highly magnetized mineral in its crust? Would it affect the rest of the chemistry on the planet? Would it cause the ground to interact with its star's magnetic envelope, like our atmosphere within the Auroras does?

Putin and Xi fantasizing about immortality via 3D-printed organs quite starkly illustrated that many adults do not understand the difference between science and science fiction.

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