We can always estimate, even with very little knowledge—we’ll just have huge error margins. I agree it is possible that “For all we know 10^20 evolutions each in 10^50 universes that would in principle allow intelligent life might on average result in 1 general intelligence actually evolving”, I would just bet on a much higher probability than that, though I agree with the principle.
The evidence that pretty smart animals exist in distant branches of the tree of life, and in different environments is weak evidence that intelligence is “pretty accessible” in evolution’s search space. It’s stronger evidence than the mere fact that we, intelligent beings, exist.
Intelligence sure. The original point was that our existence doesn’t put a meaningful upper bound on the difficultly of general intelligence. Cephalopods are good evidence that given whatever rudimentary precursors of a nervous system our common ancestor had (I know it had differentiated cells, but I’m not sure what else. I think it didn’t really have organs like higher animals, let alone anything that really qualified as a nervous system) cephalopod level intelligence is comparatively easy, having evolved independently two times. It doesn’t say anything about how much more difficult general intelligence is compared to cephalopod intelligence, nor whether whatever precursors to a nervous system our common ancestor had were unusually conductive to intelligence compared to the average of similar complex evolved beings.
If I had to guess I would assume cephalopod level intelligence within our galaxy and a number of general intelligences somewhere outside our past light cone. But that’s because I already think of general intelligence as not fantastically difficult independently of the relevance of the existence proof.
Hox genes suggest that they both had a modular body plan of some sort. Triploblasty implies some complexity (the least complex triploblastic organism today is a flatworm).
I’d be very surprised if most recent common ancestor didn’t have neurons similar to most neurons today, as I’ve had a hard time finding out the differences between the two. A basic introduction to nervous systems suggests they are very similar.
We can always estimate, even with very little knowledge—we’ll just have huge error margins. I agree it is possible that “For all we know 10^20 evolutions each in 10^50 universes that would in principle allow intelligent life might on average result in 1 general intelligence actually evolving”, I would just bet on a much higher probability than that, though I agree with the principle.
The evidence that pretty smart animals exist in distant branches of the tree of life, and in different environments is weak evidence that intelligence is “pretty accessible” in evolution’s search space. It’s stronger evidence than the mere fact that we, intelligent beings, exist.
Intelligence sure. The original point was that our existence doesn’t put a meaningful upper bound on the difficultly of general intelligence. Cephalopods are good evidence that given whatever rudimentary precursors of a nervous system our common ancestor had (I know it had differentiated cells, but I’m not sure what else. I think it didn’t really have organs like higher animals, let alone anything that really qualified as a nervous system) cephalopod level intelligence is comparatively easy, having evolved independently two times. It doesn’t say anything about how much more difficult general intelligence is compared to cephalopod intelligence, nor whether whatever precursors to a nervous system our common ancestor had were unusually conductive to intelligence compared to the average of similar complex evolved beings.
If I had to guess I would assume cephalopod level intelligence within our galaxy and a number of general intelligences somewhere outside our past light cone. But that’s because I already think of general intelligence as not fantastically difficult independently of the relevance of the existence proof.
This page on the history of invertebrates) suggests that our common ancestors had bilateral symmetry, triploblastic and with hox genes.
Hox genes suggest that they both had a modular body plan of some sort. Triploblasty implies some complexity (the least complex triploblastic organism today is a flatworm).
I’d be very surprised if most recent common ancestor didn’t have neurons similar to most neurons today, as I’ve had a hard time finding out the differences between the two. A basic introduction to nervous systems suggests they are very similar.