I was only gone for a day or two...

First: your tone is highly combative. I wouldn't be shocked if this is part of why you don't have productive conversations most of the time. I'm a pretty coolheaded person, but being Internet-shouted at does not tend to bring out the best in people.

Ironically, given the vegan stereotype, you are the one why has levied personal accusations, not me.

Your utilitarianism equates mass slaughter with ‘the least suffering’. That is monstrous.

What?

Does "mass slaughter" not describe the current state of affairs, except on a daily basis? Something like 5 billion animals per day, 1 trillion per year (including fish)? 1 billion pigs, each of which us as smart as a toddler, per year?

I'm proposing slaughtering animals that were already going to be slaughtered. The only difference is timing, right? Seriously, am I missing something?

Surely the anti-vegan position must also consider mass slaughter, in the most dispassionate and literal sense of the word slaughter, to be acceptable.

Species extinction is a great tragedy, and it is happening at a frightening pace.

If you care about biodiversity, you really don't want to be arguing the anti-vegan position. A huge portion of species extinction is a result of habitat loss, a huge portion of which is caused by clearing land for cattle ranching. If you want to reduce your personal impact on biodiversity, don't consume cow products.

Domestication is mutualism, animals receive great benefit from it in the form of better nutrition and medical care. You treat it as some form of inhumane torture and deny its greatest benefit. I cannot accept your arguments here.

I can't see how you can possibly argue that animals in the meat industry have a good quality of life (on average; I'm sure there are exceptions). Jesus, have you seen the conditions they're kept in? Have you seen the chickens so large they can barely move? Have you seen what they do to male chicks? This is, like, the core emotional reason why people go vegan to begin with.

And here the bullshit begins. I never ONCE fucking invoked a supernatural deity here and was SPECIFICALLY referring to how our diets have shaped our physiology over the last several hundred thousand years. Honestly I wanted to just stop this discussion here and block you, but I am trying to be a better person no matter how hard you make it.

Please, please. Please assume good faith on my part. (Don't be so unreasonable.)

Of course you never invoked a deity. That was a rhetorical gesture on my part. The point is that there is no telos in nature. You cannot get directly from a state of affairs to a conclusion about how things ought to be.

I have particular qualm with arguments of the form "We evolved doing X, therefore we're meant to do X, therefore we should continue doing X", because they typically imply that evolution has some kind of normative quality to it, which it simply doesn't.

No I wouldn’t, not at all, in fact I abhor the fact that agriculture ever became a thing.

You know what? I respect that stance. I used to believe it wholeheartedly, but I have a lot of reservations about it these days. I don't think you should judge me too harshly for assuming the opposite, though---you're part of an extreme minority.

But my original point stands---unless your argument is that we should live as much like hunter-gatherers as possible, in which case, well, I suppose that's a consistent position---but in that case, I think you ought to be focusing your energies arguing against cheeseburgers, because "plant-based"-type vegans have a diet much closer to prehistoric humans than the average Westerner.

We are the products of a ridiculous amount of specialization that even cutting edge medicine is only now beginning to understand, your embrace of ‘unnatural’ solutions (which is a stupid phrase all things considered we are a part of nature) is ill-planned as far as outcomes. You make ASSUMPTIONS that certain outcomes are the only result with no evidence, when the real world is rarely ever amenable to such clear cut cause and effect relationships.

The original question was: "Do you not think the critical need for specific supplements to maintain good health is a sign that the diet was never intended for our normal operation?" But it seems that what you really mean is: since vegans need to take supplements, maybe it's impossible for the vegan diet to ever be truly healthy. Maybe that should have been obvious, but I'm autistic, so I tend to assume that people mean exactly what they say.

My answer to the latter question is: maybe! But I'm doubtful. I see vegans who are doing just fine, so I really do think there's no fundamental reason why a vegan diet can't be healthy. And, really, I don't even see how it could be true. In the worst case, anything that we normally get from animals can be synthesized, or even grown in a lab.

In any case, I see suffering and I think we should be willing to take personal risks to reduce it. I don't think that idea, on its own, is so crazy. Remember, I am not arguing in favor of, like, legislation; I'm arguing that people should make these choices voluntarily.

It is an established fact that pets are healthier and longer lived than their wild cousins, this is one case where you choose to ignore your utilitarianism because it conflicts with your groupthink.

I did say I was undecided. I'm not interested in arguing over points that I haven't even endorsed.

There is clear evidence that even non-vegan infant formula causes long term health issues and that the only complete nutrition we have now for infants is human breast milk. I do not see how a vegan solution could even come close.

Why on Earth would I have an ethical objection to voluntarily-given human breast milk? That is vegan, by any reasonable definition. I thought you were talking about raising an infant with, like, vegan baby food.

I have no objection to the substance of animal products itself, or else I wouldn't be suggesting lab-grown meat as a future possibility.