The above title is a question that I have encountered in vegan advocacy. Recently, someone with whom I was speaking answered the question himself, his answer serving as justification for his continued use of animals. He asserted that, "If we went vegan, they would no longer exist." Being in the middle of a discussion, and certainly not as articulate on my feet as I am on a keyboard, I tried to address his concern as best I could. I felt that I did a fairly good job, but having had time to think about it, I would like to offer some further thoughts on this topic, expanding upon my original response.
A) This assertion assumes that being alive [regardless of the quality and quantity (length) of one's life] is better than never having been born, never having existed at all. It depends on a hypothetical (and false) dichotomy, though, where the only two choices are 1) living for a short amount of time in an unhappy life or 2) never having been alive. While that may lead to a fun little philosophical discussion, none of us were given the opportunity to make that choice for ourselves, so assuming that the animals where able to weigh the pros and cons before we bred them into existence doesn't make any sense.
B) While I do not want to diminish anyone's concern, I would like to point out that the individual animals that are raised and killed for food cease to exist the moment they are killed for a non-vegan's meal, not the moment that a person becomes a vegan. If a concern is truly present regarding the alive (or not-alive) status of animals, going vegan is the only appropriate response.
C) As much as I and other vegans would undoubtedly hope, the world is not going to go vegan overnight. However, additional concerns that I have encountered regarding the possibilities and what we would do in such a situation all seem rather extreme to me.
1) "If everyone went vegan, we'd have to kill all the ("food") animals currently in existence." First of all, no. I don't think anyone ever said that that would be the appropriate response, and I think you would be hard-pressed to find a vegan who would advocate killing animals in such a scenario. However, to examine this idea, I would turn this back to you and ask, They are currently (today) being killed for food, so why does the idea of killing them in this scenario trouble you if not for the fact that, as vegans, we would no longer benefit from their bodies? In this mindset, animals exist only for our purposes, for how we benefit from them. Without us benefiting from their use, they have no purpose and their deaths are worthless, pointless, and a waste.
2) "If everyone went vegan, we'd have to let all the ("food") animals free, and they would be killed by predators." Other than us, you mean? In all seriousness, I can see where people might believe there to be a difference between humans killing animals and other animals ("predators") killing animals. For many, the prevailing belief is that since we are humans, we would only act in a "humane" way, regardless of evidence to the contrary. The assumption is that when we kill animals for food, we do it "nicely," whereas predators kill "like animals." This belief, however, is not only faulty (and speciesist) but also misleading: It doesn't matter how "nicely" an animal is killed when the fact of the matter is that he/she shouldn't have been killed in the first place.
3) "If everyone went vegan, we'd have to let all the ("food") animals free, and they would reproduce like crazy and overpopulate the land." Too much of a good thing is a bad thing, I guess. To ease concerns here, I would remind you that many domesticated "food animals" cannot reproduce naturally. Most are the result of artificial insemination. Because of the ways that we have manipulated their bodies to make them more productive, more worthwhile for our consumption, they are physically unable to mate with others of their species. And anyways, even if they could, any predators (see above) would keep the population in check.
While that's how I would think to address the above concerns, in all honesty, the only thing that really needs to be said is that as people go vegan and demand lowers for animals and their products, fewer animals will be bred into existence. It's as simple as that. There will be no need for us to kill them or set them free when the world is vegan, for at that point in time, the few "food animals" who remain would be cared for, allowed to live out the rest of their lives in peace.
So, in working through all this, I have a new, honest response to the question, "If we all went vegan, what would happen to the animals?"
They would no longer exist for our purposes.
If we all went vegan, they would no longer be used by us, enslaved by us, killed by us.
If we all went vegan, the animals could exist on their own terms, for their own purposes.
If we all went vegan, they would no longer be "food animals," "research tools," "clothing options," "entertainment," or "toys."
If we all went vegan, the animals would be able to be themselves, no longer defined in terms of their use, their worth to us.
Please go vegan and encourage others to do the same!