Does the fact that many non-human animals have pituitary disprove Cartesian Dualism?

[FlatAssembler]

I think we all know what we mean when we say "feel pain", there is no need to define it. Some things, such as "knowledge", are difficult to define, but we all know what they mean, and asking somebody to define it is derailing a discussion.

It’s not derailing at all. In fact, it’s a very pertinent question. 

Boru

So, you are a rationalist rather than an empiricist? You think that the more our philosophy looks like the Euclid's Elements, the better? Well, I am telling you, that way of thinking is useful in geometry, but almost everywhere else though, it leads us nowhere.

Some arguments for fish not feeling pain are "It appears as though type-c neurofibres are necessary to feel pain, because people with congenital analgesia have a smaller proportion of the type-c neurofibers. And fish have little or no type-c neurofibers." and "Fishes with a hole in their fin continue swimming as normal.". Completely empirical, not trying to rationalistically define pain.