Agree. the road from creation of life to creation of any nervous system at all is an extremely long and fraught one.
Life on our planet has a very specific chemistry. It’s possible that almost all possible chemistries limit complexity more than ours—leading to many planets of very simple organisms. Very large number of phyla on earth reach evolutionary dead ends both archae and bacteria are stuck as single cellular organisms, (or very simple aggregrates) - Plants cannot develop movement because of their cell walls, while insects cannot grow bigger because their lungs and exoskeletons do not scale upwards.
Genetics is an entire optimization layer underlying our own, neural one. I think the fact that it had to throw up an entire new, viable optimization layer represents a filter.
This is another good explanation instead of / in addition to the Great Filter.
It could be that there are many local optima to life, that are hard to escape. And that intelligence requires an unlikely local optimum. This functions like an early Great Filter, but in addition, failing this filter (by going to a bad local optimum) might make it impossible to start over.
For example, you could imagine that it were possible to evolve a gray goo like organism which eats everything else, but which is very robust to mutations, so it doesn’t evolve further.
Yes. And this is what has happened to most branches of the tree of life. E.g. Archae Bacteria, the various Protists. Only very basic multicellularity occurs in most kingdoms.
Could it be that different niches of life don’t independently evolve because those niches are already being filled? Can we say with confidence that if all animals died, something like animals wouldn’t eventually evolve again? Or any order of life.
That’s a good point. I guess not. My intuition is that a lot of organisms have evolved simple multicellularity, and so would probably be doing better as unified multicellular organisms, but it’s possible, as you say, that they haven’t gotten to that point for lack of the niche. I don’t know enough about the topic to say.
Agree. the road from creation of life to creation of any nervous system at all is an extremely long and fraught one.
Life on our planet has a very specific chemistry. It’s possible that almost all possible chemistries limit complexity more than ours—leading to many planets of very simple organisms. Very large number of phyla on earth reach evolutionary dead ends both archae and bacteria are stuck as single cellular organisms, (or very simple aggregrates) - Plants cannot develop movement because of their cell walls, while insects cannot grow bigger because their lungs and exoskeletons do not scale upwards.
Genetics is an entire optimization layer underlying our own, neural one. I think the fact that it had to throw up an entire new, viable optimization layer represents a filter.
This is another good explanation instead of / in addition to the Great Filter.
It could be that there are many local optima to life, that are hard to escape. And that intelligence requires an unlikely local optimum. This functions like an early Great Filter, but in addition, failing this filter (by going to a bad local optimum) might make it impossible to start over.
For example, you could imagine that it were possible to evolve a gray goo like organism which eats everything else, but which is very robust to mutations, so it doesn’t evolve further.
Yes. And this is what has happened to most branches of the tree of life. E.g. Archae Bacteria, the various Protists. Only very basic multicellularity occurs in most kingdoms.
Could it be that different niches of life don’t independently evolve because those niches are already being filled? Can we say with confidence that if all animals died, something like animals wouldn’t eventually evolve again? Or any order of life.
That’s a good point. I guess not. My intuition is that a lot of organisms have evolved simple multicellularity, and so would probably be doing better as unified multicellular organisms, but it’s possible, as you say, that they haven’t gotten to that point for lack of the niche. I don’t know enough about the topic to say.