Mike recently directed me to a blog by a mutual vegetarian friend from college, Adam. The language is harsh: eating meat is oppression and so forth. What lovely serendipity that we covered prehistory in my development class today.
The roots of human civilization lie in what Jared Diamond calls "farmer power," or the development of food stuffs so other people can specialize in non-farming professions (soldiers, inventors, traders, etc). Critical to this was the domestication of animals for purposes of food and labor (the aforementioned oppression). Over generations brain power and survival techniques (such as good eyesight) were severely diminished. In other words, they are not natural in any normal sense of the word. Indeed they are less natural than a wooden table, since at least the wood retains original DNA. Domesticated animals are a new species.
Adam posted a few videos from Waking Life, an independent philosophical film. One character argues "the gap between, say, Plato or Nietzsche and the average human is greater than the gap between that chimpanzee and the average human," a rather strange claim given history. The average human purposefully domesticated plant and animal species, something no other animal has done. That's an astonishingly large leap from a chimpanzee.
A great departure from their wild ancestors, modern farm animals are basically bags of meat with scarcely a glimmer of intellect. They were bred to be property, and non-sentient at that (save for the most encompassing definition of sentient). Even by their cousin's standards they are stupid. Of all the oppressions of the world, meat-eating hardly seems like a worthy one to fight.