The puffer fish in the last post reminded me of this experiment with zebrafish. Again, in Godfrey-Smith’s book about the octopus:
Zebrafish were tested first to see which of two environments they preferred. They were then injected with a chemical suspected to cause pain, and in some cases, the less preferred environment had a painkiller dissolved in it. The fish now preferred this environment, but only when it contained dissolved painkiller. They made a choice they’d not normally make, and they made it in a situation where the idea of a more painful or less painful environment would be quite novel to them.”
He’s not arguing here that zebrafish have consciousness. He’s arguing that they probably do feel something, and that the feeling led to an action. In many animals, the path from sensing to action travels along a nervous system. That nervous system, he says, can give rise to consciousness, but it doesn’t have to. It can stay in the realm of “subjective experience.”
Do you think fish feel pain?