So, I’m not a biologist. I don’t think Eliezer is much of a biologist either. A thing that I learned in the last ten years, which maybe Nate and Eliezer learned in the same time, idk, is that different aquatic animals are more distantly related than one might have thought. For example, let’s take the list from 2008. When I go on Wikipedia and try to find an appropriate scientific name for each and stick it into timetree.org to try to figure out when their most recent common ancestor was, I get the following estimates:
Salmon and Guppies: 206 MYA Trout and Guppies: 206 MYA Dolphins and Guppies: 435 MYA Sharks and Guppies: 473 MYA Jellyfish and Guppies: 824 MYA Algae and Guppies: 1496 MYA
That is, if you’re going to start removing things from the list because of how distantly related they are, sharks go first; Chondrichthyes is just as weird a member of Chordata as Mammalia is, from the perspective of Actinopterygii.
The trouble with defending the 2008 classification is not that it’s phylogenetics, it’s that, as far as I can tell, it’s bad phylogenetics. And so you end up requiring mental gymnastics in order to exclude dolphins because their most recent common ancestor is too far back while including sharks whose most recent common ancestor is even further back. The pedant’s position (“I know that dolphins are mammals instead of fish!”) doesn’t hold up under either the useful definition (“dolphins are aquatic animals tho”) or the phylogenist’s definition (“mammals are chordata tho, which is what you should mean when you say ‘fish’.”).
So, I’m not a biologist. I don’t think Eliezer is much of a biologist either. A thing that I learned in the last ten years, which maybe Nate and Eliezer learned in the same time, idk, is that different aquatic animals are more distantly related than one might have thought. For example, let’s take the list from 2008. When I go on Wikipedia and try to find an appropriate scientific name for each and stick it into timetree.org to try to figure out when their most recent common ancestor was, I get the following estimates:
That is, if you’re going to start removing things from the list because of how distantly related they are, sharks go first; Chondrichthyes is just as weird a member of Chordata as Mammalia is, from the perspective of Actinopterygii.
The trouble with defending the 2008 classification is not that it’s phylogenetics, it’s that, as far as I can tell, it’s bad phylogenetics. And so you end up requiring mental gymnastics in order to exclude dolphins because their most recent common ancestor is too far back while including sharks whose most recent common ancestor is even further back. The pedant’s position (“I know that dolphins are mammals instead of fish!”) doesn’t hold up under either the useful definition (“dolphins are aquatic animals tho”) or the phylogenist’s definition (“mammals are chordata tho, which is what you should mean when you say ‘fish’.”).