Awareness of oneself is a completely different matter. The Mirror Test is far from perfect, but it does demonstrate that some individuals of some species are indeed capable identifying themselves as individuals in a group, indicating at least rudimentary sentience. There are also other tests for animal sentience, though I suspect it's hard to test many animals due to logistical reasons.
Most multi-cellular life is able to feel pain, and probably pleasure too. That includes both pigs and cows (and whales for that matter). Heck -- even plants have chemical responses to damage, even though they don't have nervous systems. Individual plants can even communicate with each other and let others know of the pain it experiences. In other words: if pain to the living being that you are consuming for food is a concern, then you should stick to eating fruit and things that are already dead.
> Individual plants can even communicate with each other and let others know of the pain it experiences.
The way cows, dogs, pigs, cats, sheep and horses express pain is very similar to humans: screaming and squirming or trembling, trying to escape, sweating, increased pulse and blood pressure, etc.
Responding to damaging stimuli is not necessarily the same, and I'm therefore not convinced that plants can "feel pain"; but perhaps neither are you? Surely you'd have a harder time grabbing a red hot iron bar and poking a puppy than poking a turnip with it? (There's a reason the killing is done behind closed doors[1].)
> The Mirror Test is far from perfect, but it does demonstrate that some individuals of some species are indeed capable identifying themselves as individuals in a group, indicating at least rudimentary sentience.
What about the individuals that fail it? I expect tiny infants to be able to fail the mirror test. That wouldn't make it ok to eat them, of course? Same argument for blind people; and of course the kind of people who, when they wake up after they've been drugged and strapped firmly to a chair in front a mirror, don't consider investigating a sticker on their shoulder as a first priority (because that's how that test works, right?).
Also pigs seem to be able to understand mirrors anyway:
> They found that pigs:
> • have excellent long-term memories
> • are whizzes with mazes and other tests requiring location of objects
> • can comprehend a simple symbolic language and can learn complex combinations of symbols for actions and objects
> • love to play and engage in mock fighting with each other, similar to play in dogs and other mammals
> • live in complex social communities where they keep track of individuals and learn from one another
> • cooperate with one another
> • can manipulate a joystick to move an on-screen cursor, a capacity they share with chimpanzees
> • can use a mirror to find hidden food
> • exhibit a form of empathy when witnessing the same emotion in another individual
> In other words: if pain to the living being that you are consuming for food is a concern, then you should stick to eating fruit and things that are already dead.
I think it should even extend beyond personal diet to preventing others from inflicting pain on the living, just like slavery was not considered a personal choice by abolitionists.
I was going to write a long rant as a reply, but it all really comes down to this:
> I think it should even extend beyond personal diet to preventing others from inflicting pain on the living
If we assume a lion (or another predatorial animal) has at least a rudimentary form of counciousness, would that mean that a lion that ate a human would feel bad about it's actions?
Lion's are not on a mental level where we can demand that of them.
Similarly vegans are generally also not arguing for dogs to have drivers license, or to give cows the right to vote, because they don't have the mental abilities to do so.
But really, the behavior of lions doesn't have anything to do with the question of whether we should keep pigs in factory farms, and whether it's ok for us to murder.
Most multi-cellular life is able to feel pain, and probably pleasure too. That includes both pigs and cows (and whales for that matter). Heck -- even plants have chemical responses to damage, even though they don't have nervous systems. Individual plants can even communicate with each other and let others know of the pain it experiences. In other words: if pain to the living being that you are consuming for food is a concern, then you should stick to eating fruit and things that are already dead.