[nihilismislove]

In this case, the ability to experience positive and negative mental states, can be used in place of consciousness.

Especially the ability to experience suffering might offer reasonable basis for approaching ethical questions.

In terms of animal rights this is as simple as assuming that at least most vertebrae experience mental states, incl. suffering, from at least shortly after birth (which we can safely do)

In terms of abortion, this still leaves us with the additional question of weighing contrary interests of 2 individuals. This is trivial when weighing the interests of pregnant person vs sth like a 10-week fetus (obviously incapable of experiencing mental states) but maybe not sufficient for arguments about 30+ weeks fetuses, depending on personal values

[pbhjpbhj]

A 10-week fetus, ie 20 weeks of gestation, can hear [1], suck, swallow. I would not say it's obvious they can't experience "mental states"; especially not as you appear to be arguing almost all animalkind can experience those states.

[1] https://medlineplus.gov/ency/article/002398.htm

[nihilismislove]

Well, that wasn't my main point and I did mean 10 weeks of gestation (just as an example).

Still, physiological responses are not the best indicator of mental states - plants and primitive animals (from sponges to bivalves) have them too, despite lacking the neurological development necessary for (or evolutionary need for) "consciousness".

[pbhjpbhj]

Your second paragraph there seems to refute your position. If you can't tell physiologically then how are you telling that "most vertebrates experience mental states". You seem to be arguing for an assumed position starting from that position (petitio principii).

And I agree that physiological responses aren't the best way to show mental states. I cry sometimes for no reason whatsoever, my eyes just leak; you can't infer fear just because a creature backs away from fire, either.

[buboard]

That is a better definition than the elusive conscious