the_dunk_tank

I agree with your conclusion (beastiality obviously bad) but this doesn’t work, “wiseness” isn’t an objective measure. We can’t actually decide what isn’t or is wise with any real consistency beyond what we perceive to be wise ourselves.

I would say that Homer Simpson continuing to eat food despite inevitably being brought to the slaughter could be perfectly wise, if he does not particularly care about his own longevity. The same would be true if he knew there was no option that would lead to him escaping. There would be no reason not to take the food, then.

Assuming that there is objectively wise decisions assumes there are objectively wise goals, and this is simply not true. There are only socially accepted goals and personally ingrained goals.

What this leads us to is the ability to simply skip all this and lead us to a much simpler benchmark: don’t do things to animals that go against the goals they have already shown. Surgery is barely permissible due to their obvious instinctual desire to live, but beastiality is not at all permissible because they have no desire to do anything like that with human beings. Most other things are fine because animals show an eagerness to do them and they do not against their goals, like training for treats.

I’m going to go through your examples to show how this heuristic works.

Another example of the "best self" thing: you should put your drunk friend to bed instead of letting him drive back to the club even if he's a shithead and will still be mad you didn't give him his keys once he sobers up.

You already know your friend does not want to die, usually, so this is perfectly fine because what they actually want aligns with what you do. If they did want to die in a car crash and not just because they were drunk or having an episode, then it’s not your fault that they can’t properly communicate that which goes against what they usually want. And, at risk of being very macabre, it is very easy to rectify if that is the case, unlike something like sexual assault which leaves permanent trauma.

Otherwise you can just say "oh whatever this pig has poor impulse control, if he could understand he'd still probably just do [whatever I want / whatever he was already doing]" and then why bother with the thought experiment, you can just treat animals as property and ignore their agency altogether.

Most pigs presumably want to be healthy and alive. Over feeding them or killing them after doing it goes against both of those things.

I suppose you could argue that I’m just rephrasing your point, but I think it’s an important way to rephrase it, because the logic of “best self” could be used to override eg kid’s consent to HRT and tell them they can’t get it, despite them wanting to, because as a Christian you think they just lack impulse control and need to be disciplined.

I believe the example you gave of a farmer projecting their desires onto a pig is the exact issue that assuming an objective concept of “best self” leads to. It assumes that other living beings have the exact same values as you, and gives you permission to do horrible things to them to make them conform to those values. We need to be willing to listen to people’s desires that go against our idea of what’s best to avoid this. Of course, after verifying that it is indeed what they actually want and not just a fleeting impulse.

CW: suicide for this part
You could perceive this as dangerous because it means it could lead to us, for instance, letting people die who are suicidal. While I understand the concern, I do think there’s a bigger issue with how we think about suicide in general. It’s pretty fucked up that we keep people alive against their consent because we’re fond of them- and then proceed to put them into horrible conditions like grippy sock jail that make their life worse. The logical conclusion of being against sanctioned suicide is worse than being ok with it. Of course, if we are going to be allowing this, we have to put measures into place to ensure people aren’t just being taken over by a depressive episode or feel pressured into death by social forces, and have a genuine, persisting desire to die, even through their moments of happiness. We need to be willing to improve everything else before resorting to such things, because many people resort to suicide due to feeling that what they want is impossible, not because they have a desire to die and of itself.