Our familiarity with the larger domestic animals tends, I think, to mislead us: we see no great destruction falling on them, but we do not keep in mind that thousands are annually slaughtered for food, and that in a state of nature an equal number would have somehow to be disposed of.
From an animal welfare point of view, the question is which is better? The method of "disposal" of man, or of nature? I tend to vote man, as the animals slaughtered for food are well-fed, generally healthy, and the actual death is quick. The animals "disposed of" by nature die of starvation and live with fear, illness and injury. A large domestic animal like cattle, horses, etc, if victims of predation are unlikely to die as quickly once attacked as they would in a modern slaughterhouse.
Darwin was talking about "larger domestic animals", not humans. To take my comments regarding the lives and deaths of larger domestic animals in farm and natural conditions and bend them towards a supposed position on my part regarding the lives and deaths of humans is fallacious, either a "strawman" or a "false analogy", or both. The analogy is false because humans aren't larger domestic animals with a large geometric population increase arrested by slaughter for food. If small, furry creatures from Alpha Centauri raised humans for food, then perhaps the situation would be analogous. But they aren't, as far as I know.
It's true that the populations of cattle, sheep, goats, pigs, and other larger domestic animals used as foodstock would not be as large (if at all) without the farming system, or domestication in general. But if you wish to eliminate the farming system, you need to specify an "end game". PETA would release into the wild. Darwin points out what has to happen if the populations are to stabilize if released into the wild.
Why do you need to specify an "end game". I doubt PETA would actually suggest you release domesticated farm animals into the wild, but again, I'm not a member and haven't read much of their literature.
IF everyone did slowly become veg over time, ideally towards the end there would be a place much like the current farm sanctuaries where the animals could be cared for by humans until their natural deaths without increasing their populations.
There is no mercy in death in a slaughterhouse. If someone was really so worried about the animals at the end of farming then perhaps the animals, no longer having an environment or instincts to live in the wild would be killed, I think euthanasia without the use of it's body afterwords by humans might be in order.
If that is indeed an accurate statement of your position, then we are far enough apart in this discussion that we will never reach common ground and further debate is a waste of both of our times.
And I do think that it's valid to make a comparison to humans to see if such an argument would hold true if its our own species.
I've given money to these folks because I like the idea behind what they do, and wish they could be more viable at it, but I have no illusion that they, or PETA, will ever succeed in ending the practice of industrial food-animal production. If that practice ever ends, it's far more likely to be because of those of us who participate in and evangelise the locavore movement and do our best to consume only locally and humanely raised meat whenever feasible.
I don't think we have to ponder the "end game" all that much because it's just not real likely anytime in my lifetime.
I have a community farm share and totally love it... and while I'm not hugely evangelizing I do talk about it a fair amount. I'm fortunate to live in a city/area with a very large locally grown movement.
I do support the movement to make regulations for conditions to be better for animals in farming, while I think it's ideal to be veg (and local) I don't really expect the country (or world) to move to my ideal.
PETA
You should probably keep them out of your discussions. They are a bit extreme.
" I'm not a member of PETA, but an animal welfare advocate wouldn't argue that these animals should be released into the wild, it would argue that they should never be "created" in the first place. "
Logically that means you are in favor of the extinction of domestic animals.
Re: PETA
I am in favor of the extinction of domestic animals raised for slaughter, you are correct. The wild versions of these animals will still exist where there are habitats.
What's the point of keeping an animal alive only to exploit it? How does that benefit that species at all? IMO, it doesn't. I don't expect this to happen btw, but I am in favor of it.