Dietary (and related) ethics [split from Do plants have minds?]

[Laird]

Leaving aside the medical questions relating to vegan/vegetarian diets

Framing matters, David. One could equally or even better frame that as: "Leaving aside the questionable healthfulness of a diet that includes animal products compared to a well-planned one that does not."

we come to the complication that your conviction would, if generally followed, give us a world in which a lot of species would be all but wiped out.

All the animals that provide meat or milk would either be killed, or at best be allowed to die of old age without being replaced. Maybe some would be kept, but the vast majority would cease to exist.

Again, framing matters. A massive excess of farm animals exist - who otherwise wouldn't have existed - because we humans deliberately breed them at scale for selfish purposes. When we stop artificially breeding them, their numbers will simply return to what they would have been prior to our intervention, in the ecosystems in which they originated - at least, where we haven't wiped those ecosystems out. So-called ferals will of course also continue to exist - at least, where we don't deliberately wipe them out.

Another consideration is that some animals have been bred to have cruelly fragile bodies: chickens bred for meat, for example, have been bred to now grow so rapidly that their bones often break under their own weight. It seems uncontroversial that - absent human selfishness - it is best that breeds like that do go extinct, in favour of, in this case, chickens with healthy phenotypes.

Finally: of course I don't advocate for animals to be killed during the switch. I do think that on land on which they are non-native though - such as Australia - they ought to be neutered prior to being released from their cruel confinement, so, yes, I endorse your sentiments that they be allowed to die of old age without being replaced.

I suppose that cats could be permitted to continue as feral animals that would kill and eat other animals, but pet owners would not be able to feed them.

Nutritionally complete vegan cat food exists.

The situation in relation to dogs isn't totally clear to me.

Nutritionally complete vegan dog food also exists.

What would you do about zoos? Would you let them keep their big cats, and other carnivorous animals?

Only in the exceptional circumstance in which those animals would not be able to survive in the wild, such as if they have been too badly injured, and not in the confines of a zoo: only in an area in which they can roam freely.

If so, they would need a supply of meat!

That's a genuine moral quandary. Is the injured lion painlessly put to death to save the live of the wild animals - his/her natural prey - which would otherwise have to be hunted and killed by humans to feed him/her, or are the lives of those wild animals taken to keep the lion alive? I don't have an immediate resolution to it. There might not even be an incontrovertible one. Either way, one or more animals die early.

Also fields are treated with animal dung as part of keeping the soil in good condition. I am not sure if there are good alternatives to this, but are people going to keep flocks of animals just to supply dung?

There most definitely is an alternative to this: synthetic fertiliser produced via the Haber-Bosch process, which, it's estimated, now supports approximately half of the global population.

Since you have repeatedly stated your conviction about these matters, I think it is reasonable to expect you to have thought out the consequences of your change.

Indeed. Now, will you finally answer the question I have put to you (multiple times)?