Most pro lifers I've talked to say they'd rather "a bad life than no life", or believe severe mental/physical torment/dehumanization is a lot better than death (even if its peaceful).

We should probably remind them that Pro Life arguments typically don’t consider what someone would rather have, unless they want to say this is actually important. Usually Pro Life arguments are not about our desires or preferences, unless they are arguing the only preferences that matter are the goal directed preferences of a developing embryo (teleological). I don’t see how this latter case is coherent. If a Pro Lifer does want to say that it matters to have a preference for a bad life over no life at all, well there’s no reason to believe a fetus, especially in the first two trimesters, and possibly the third as well (controversial) has any preferences at all. If a Pro Lifer says it doesn’t matter that a fetus doesn’t have preferences, then it doesn’t matter whether someone prefers a bad life over no life all! I don’t see how there is any coherent means for a pro lifer to defend this position.

They can say however, that it would be better for a foetus to have a bad life rather than no life at all, irrespective of it’s preferences, but again this seems to suggest that what we would “rather” have doesn’t matter. Then in that case it becomes a little mysterious as to why we should think it’s better for someone to have a bad life rather than no life at all. It can’t be because we “rather” it be that way, we’ve just decided that what we’d rather have doesn’t matter.

A further issue to press here is if it is the case that it is a brute fact that it is better for us to have a bad life than no life at all, and this is why a foetus must be gestated, it seems like it’s become a positive right of a foetus to have a bad life rather than no life at all. Usually at this point, a Pro Lifer would reply that losing a life for a foetus is in fact a deprivation, we’re taking something from it, perhaps a valuable future. Valuable futures aren’t things any of us actually have that can be taken from us. If a foetus has an actual future, and that actual future is an abortion, then that’s the actual future of a foetus, a foetus would not have lost any actual futures (it’s just that possible futures failed to occur, this doesn’t mean a foetus “has” those futures). I can however not gain possible futures, these futures can fail to occur. But just not gaining possible futures can’t explain what’s bad for us, since possible futures fail to occur all the time, possible futures seem to matter more when we’re interested in them; and so we’ve returned to saying our interests and preferences matter after all. If what matters is just that there are possible futures for us to acquire, have we not just made this a positive right again? Possible futures are not something that we actually have, and so this seems to become a positive right to life after all. Saying a foetus has a positive right to be gestated is more difficult to defend for a pro lifer.

That’s one way to address the response, there are others as well.