But sometimes it sound like many people think that's the only way life can start, yet we have no idea how it really works. Also on earth there are organisms in the deep sea that have completely different biology. We might find life, even sentient one, in places we haven't thought to look.
In any case, it is just way more likely than any other form and makes absolutely the most sense to look for this first.
Sure, you can always say that we don't know what we don't know, but the periodic table of elements is finite and complete, and we are pretty sure that chemistry doesn't change across the universe. I realize I'm fighting an uphill battle in my position, because it's hard to prove the non-existence of things, so you will always be able to say "whatever, maybe you didn't think of everything", and it's true, but I have a hard time seeing how life can be anything but carbon-based. If you have more insight besides what resembles a god of the gaps, I'd be very interested.
Are there elements that are more stable under high pressure or heat? Or opposite?
What does that mean? The parent’s point was that this isn’t just a matter of looking for what is already familiar, but a matter of through the lens of what affordances the elements have and therefore what, in principle, is likely or even possible, to the best of our physical/chemical knowledge.
There’s a rational middle ground between parochialism and anything goes.
People are working on diamond-based semiconductor devices, and organic-transistors are built experimentally all the time (nothing commercial but it's an area of active research).
An advanced bit of nanotechnology that could self-repair would likely consist of a computer chip which fabbed up replacement organic components for itself and could transport and replace them in-situ, even if it was still just a computer otherwise being digital - after all, that's how our cells do it.
But they're both one of the most common elements either way, so I think other properties would be more important.
The way the GP comment describes carbon-based technological life made out of transistors doesn't sound like the metabolize carbon to CO2 or would require a lot of water, though, which are two important markers when searching for life.
I don't think I do. Or maybe I misunderstand what "digital intelligence" means.
> if you have carbon-based life forms, you will have water and CO2.
..can lead to statements like:
> it is just way more likely than any other form
I totally agree on the observation, but what is fascinating to me is why a deductive statement can be considered to indicate likelihood in probability. It seems there is a bit of abductive reasoning going on behind the scenes which neither the deductive logic or inductive probability can really capture on their own.
You're right. Absolutely, completely correct. There's almost certainly other ways life can start. Other processes that can result in intelligence. Other paths of technological development.
The issue, as I understand is, is that all of those are completely unknown. We have absolutely no useful idea of how to look for wildly different life in places we haven't thought to look.
What we do know with certainty is that Earth's chemistry can result in life. We do know that it can result in intelligence. We do know what paths our technological development took. We even have some idea what these things might look like from afar. All together, we have exactly one data point that lets us search for similar data points.
Are there other, different world, with different life? Very possibly. We humans are well aware of this. We just don't have a way of knowing if we've found anything. So as a matter of managing limited resources, there's a tendency to stick to what we know can work.
Inevitable Wikipedia article about this:
https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
The approach of "Smart people have thought of that, there are very few chemically useful alternatives" is the kind of thing that entrenches a person in their insistence that this is just a wide-scale failure of imagination. Witness their comment about "earthlike biology perspective". They want to believe a wider, weirder universe is possible. As a rule, it helps people feel heard to tell them they're right about something.
So yes. I'm going to present it as a staunch certainty that something else is possible but currently unknowable, invisible, and irrelevant. I'm doing this in the hopes that the message gets through that this is not simply parochialist arrogance at work, from which they might nobly dissent.
First order life, but what about second order?
If I make a complex 'mechano-computer' that can reproduce itself, how exactly is that different from life? Now it looks like the universe doesn't have any direct way to go to silicon based life, but indirection over carbon based life first seems very possible.
We know that Earth's chemistry can _support_ life. Panspermia is still a plausible explanation for life on Earth.
Lots of other biochemical similarities, too.