I'm quite alright with people not being vegetarian if causing harm to animals is morally wrong and the meat-industry is abolished (consequence of premises 1-3), since then humans would only continue to eat meat if the animal died due to natural causes, or if they continued to purchase meat from illicit meat-providers.

Living a life which was natural and not dependent upon the luxuries of civilization.

How would abstaining from meat deprive me of civilization's many luxuries?

I think you're backing off a bit too much now. The important question remains: Why is it wrong to eat an animal that has been killed by someone else? I say that this question is important because your answer has not been clear or satisfactory. There are two ways that people can object to you: (i) harming animals is not morally wrong and (ii) harming animals is wrong, but that it is irrelevant since most meat-eaters don't harm animals. I have chosen the second way because it is, in my view, more relevant to your conclusion that people should be vegetarian, because many people who eat meat don't harm animals in order to eat meat. It is these people who, you could say, I am representing. I also find it to be a better attack on your argument, since you presuppose that causing harm; I accept your presupposition, but then try to show that the conclusion does not follow

Your reasoning implies that you can't do anything that harms animals or humans, right? (If it's not overridden.)

I'm quite alright with people not being vegetarian if causing harm to animals is morally wrong and the meat-industry is abolished (consequence of premises 1-3), since then humans would only continue to eat meat if the animal died due to natural causes, or if they continued to purchase meat from illicit meat-providers. The major thrust of the argument was to get across that harming animals is wrong, so even if we concede that simple meat-eating is okay, the real problem lies with killing animals for meat, which provides the meat to meat-eaters in the first place.

Right, but we've come to the agreement that oil consumption or meat consumption are not themselves complicit in the moral wrongness involved in their extraction/slaughter, so I can still drive my car and eat meat (if I come across something already dead, since the meat-industry is gone).

Ok, but the meat industry would only be gone if everybody were adhering to morality.
And if someone is killing animals despite, buying the meat is not immoral for you.

You are aware we have ways to kill animals that are completely harmless, right? Excuse my memory, but I recall an item that sends a concentrated stream (this is an understatement) of air into the skull of an animal, killing it almost instantaneously. Though this is obviously not widely used because of expense, theoretically, if it were implemented, would you then be OK with the meat-industry? Or is the killing (besides the circumstances we spoke of) the real issue?

Indeed, one can only hope that an ethical argument carries sufficient force to push for legislation that will uphold its conclusions. Murder is considered morally wrong, and our legal system reflects that principle, but people will continue to murder.

Inflicting harm on an animal exactly is violating its basic welfare interests, and that includes killing it.

Indeed, one can only hope that an ethical argument carries sufficient force to push for legislation that will uphold its conclusions. Murder is considered morally wrong, and our legal system reflects that principle, but people will continue to murder.

Wouldn't that depend on one's morality? I can think of several instances where I'd consider murdering (humans) to be fine.

I still haven't received clarification on why animals are sentient. I'm aware animals can feel, but I'm not wholly convinced they can experience (qualia) as humans can. Do you have any evidence of such? Many believe qualia is only present in humans.

And how far down do you define "animal"? Are worms "animals"? Insects? What is the break-off point?

But where's the argument that supposes they have "basic welfare interests"? Should I just assume they do?

But where's the argument that supposes they have "basic welfare interests"? Should I just assume they do?

You might argue that I am applying "intrinsic worth" to basic welfare interests, but I regard these interests as an empirical reality based on the observation that sentient beings generally exhibit an interest in living through their behaviors; in particular, this interest in living is reflected in the observable life-affirming and danger-avoiding behaviors exhibited by sentient beings. Therefore, the way in which basic welfare interests avoid appealing to intrinsic worth is by applying wrongness to an action derivatively on the basis of whether that action clearly harms (i.e., thwarts, sets back, or defeats) the observable life-affirming behaviors exhibited by sentient beings. So, in essence, it is this empirical reality which provides the derivative, not intrinsic, foundation for basic welfare interests.

I thought it was sort of an assumption to start with that harming animals is wrong.

Not necessarily, here's a previous post of mine which attempts to get around wholly assuming basic welfare interests:

Their "sentience" does not equal our "sentience". This is undetectable, as noted. I ask, once again, how far do you stretch "sentience"? There is a difference between us and a walrus, in terms of "sentience". There is a difference between a walrus and an earthworm, in terms of "sentience".

Where are you stopping in your moral judgment? Where are you beginning? But most importantly, I need to know what you mean by "sentient", because it is not always the same for different species.

And I was willing to make that assumption just on the basis of accepting his logical argument, but now he really wants us to delve deep. I can no longer just assume this to be so. Humans have semantic and experiential capacity that far surpasses that of an ordinary "animal". The cut-off point (of making it illegal to kill humans, and not most animals), seems logical to me. We cannot account for every single "animal", we cannot evaluate the consciousness of every single living organism.

I feel there's a difference in sentience. The "interests" you speak of, are not the same type of "interests" representative in humans -- Our semantic, experiential, and communicative capacity is far beyond that of any species we have encountered thus far. This difference in sentience allows me to consider it morally acceptable to kill some animals (and all fish).

I admire you, but I do not agree. I have no moral obligation to animals, just as they have no moral obligation to me. Before this morality we're so proud of, it was a kill or be killed world. It still is, but we now have the option to defy it. I'm not saying you're wrong for doing so, but I fundamentally can't find a reason why I would.

So, let's be clear: I understand you feel you have a moral obligation, and I also understand you're still going to draw a line based on the knowledge you have at any given point in time. On my end: Just as I have no regret for eating plants, I have no regret for eating animals, just as I have no regret for eating insects. I do not feel these creatures have the same "sentience" we do, and thus do not find it morally obligatory to refrain from consuming these creatures.

Thank you for the intelligent discussion.

OP, you said that you apply intrinsic worth to basic welfare interests because (e) it is an empirical reality that sentient beings generally exhibit an interest in living through their behaviors. I agree with (e); I think this is a reasonable observation. But how do we go from (e), the observation that sentient beings have an interest in living, i.e., have an interest in preserving their own existence, to the idea that it is wrong to harm others because doing so thwarts their interests?

This question is a general one, but it does have implications to your argument; it also, to be fair, has implications on any other-regarding moral judgment.

Okay, but just to clarify that our basic welfare interests are the same, despite the differences in intellectual capacities between species:

Basic welfare interests include, but are not necessarily limited to, the continuance of one's life, physical health and vigor, the integrity and normal functioning of one's body, the absence of absorbing pain and suffering, emotional stability, a tolerable social and physical environment, and a certain amount of freedom from interference and coercion. These welfare interests are the very most important interests, not only because they are definitive of basic well-being, but also because their realization is necessary before one can satisfy virtually any other interest or do much of anything with one's life. We cannot achieve our ulterior interests in a career or personal relationships or material gain if we are unhealthy, in chronic pain, emotionally unstable, living in intolerable conditions, and are constantly interfered with and coerced by others. When basic welfare interests are defeated, a very serious harm has been done to the sentient possessor of those interests, no matter what species it belongs to.

The animals you speak of are not concerned with "health and vigor" the same way (or to the same length) that humans are. Humans have an understanding (and concern, whether it be of vanity, medical health, etc.) of the body far beyond that of what an animal is able to realize.

The animals you speak of do not contemplate "emotional stability". There is no critical thought on emotional well-being.

The animals you speak of are not concerned with the same social environment we are: Our concerns of love, hate, and social concerns are infinitely more complex due to our semantic allowance. Most "social" interaction in animals is instinctual.

We cannot say animals have "ulterior motives or interests" in the same breathe as the human variation we're referring. We can most certainly argue humans hold a sense of intent, which is much more complex than that of other creatures.

And note, I use "animals" very loosely, as each species can vary, sometimes immensely, in their capacity in any one of these areas. Needless to say, humans far surpass even the most intelligent "animals"

Thus, I'm not wholly convinced "animals" have "basic welfare interests".

You might argue that I am applying "intrinsic worth" to basic welfare interests, but I regard these interests as an empirical reality based on the observation that sentient beings generally exhibit an interest in living through their behaviors; in particular, this interest in living is reflected in the observable life-affirming and danger-avoiding behaviors exhibited by sentient beings. Therefore, the way in which basic welfare interests avoid appealing to intrinsic worth is by applying wrongness to an action derivatively on the basis of whether that action clearly harms (i.e., thwarts, sets back, or defeats) the observable life-affirming behaviors exhibited by sentient beings. So, in essence, it is this empirical reality which provides the derivative, not intrinsic, foundation for basic welfare interests.

The concern in animals of their interests is recognitions-based (human observation):

Indeed, it is. And through my human observation, I've come to the conclusion "animals" are not the "sentient" you describe.

...and I feel your paragraph on "basic welfare interests" is misleading at best in regards to "animals".

Until you address each aspect of life you brought to the table, explicitly stating how there is "little difference" between us and the "animals" you feel morally responsible for, I don't know how else to continue.