âDolphins are fish because if they werenât, then I would be very sad and might kill myself. You ought to accept an unexpected acquatic mammal or two deep inside the conceptual boundaries of what would normally be considered fish if itâll save someoneâs life; thereâs no rule of rationality saying that you shouldnât, and there are plenty of rules of human decency saying that you should.â
So, insofar as the category âfishâ was supposed to be about animal biology and not social practice, this is of course antirational. But, say itâs the case that if dolphins are fish, then I would be very sad and might kill myself. This isnât purely about animal biology, it also involves my values, and so almost certainly involves other facts, e.g. how I and others will relate to tr⌠dolphins. Just like convergent evolution somehow âoverlaysâ or âoverlapsâ phylogenetic descent, as a usefully-separately-conceived causal/âexplanatory factor, so too might these (additional, non-biological, partly social) concepts about dolphins overlay the (also useful, biological) concepts about dolphins.
So, insofar as the category âfishâ was supposed to be about animal biology and not social practice, this is of course antirational. But, say itâs the case that if dolphins are fish, then I would be very sad and might kill myself. This isnât purely about animal biology, it also involves my values, and so almost certainly involves other facts, e.g. how I and others will relate to tr⌠dolphins. Just like convergent evolution somehow âoverlaysâ or âoverlapsâ phylogenetic descent, as a usefully-separately-conceived causal/âexplanatory factor, so too might these (additional, non-biological, partly social) concepts about dolphins overlay the (also useful, biological) concepts about dolphins.