To me, there are some practical considerations to questions of vegetarianism that I think are important to remember, outside of the moral arguments that are put forward in my book.
It is true that a highly retarded human being may not be a whole lot more intelligent than a chimpanzee, but the reality is that very few people want to eat either apes or people, so I don't consider that to be a highly pressing issue, to say the least.
Secondly, I do think that it is a slippery slope to say that eating plants is "better" than eating animals -- plants certainly seem capable of feeling pain, and I'm not sure where the clear demarcation is betwee, say, lizards and plants -- if we are going to say that it is okay to eat the category "plants" but not "lizards" - then we are already saying that a category called "less intelligent/less aware" is okay to eat, which also would include "humans" versus "animals/plants."
Thirdly, I think it's also important to remember that if we stop eating animals, we will not treat the ones we have better -- which certainly would be great of course -- but all that will happen is that we will have fewer animals. It seems quite possible that cows would become extinct -- or close to it -- and perhaps chickens and pigs as well, so I'm not sure that would be a better solution for them.
Fourthly, one of the reasons I think that animals are treated quite badly in domestication -- and why we eat them in such quantities -- is because the true cost of meat is obscured by near-universal government subsidies. Of course we are all aware of the fact that it takes 7 pounds of grain to create 1 pound of meat -- as well as a prodigious amount of extra water -- and yet grain does not cost a tiny percentage of meat -- that is because of government subsidies, which of course should be -- and would be -- eliminated in a voluntary society. This would result in vastly increased prices of meat, relative to vegetables and grains, which would reduce demand, and thus reduce the number of domesticated animals designated for slaughter.
Fifthly, if we do have the goal of raising our empathy towards animals -- which I think is a fine idea -- then I think that we face the requirements to first raise people's empathy towards human beings, which seems far easier, although still terrifically difficult.
For instance, it seems impossible to imagine that Americans would become more empathetic towards animals before they become more empathetic to the victims of US imperialism, such as the innocent Iraqi civilians who are murdered by the tens of thousands.
Thus the goal of raising empathy towards animals has to go through the requirement of raising empathy towards humans. And of course there is no way to raise empathy towards others without raising empathy towards oneself, which is the great challenge of self-knowledge and gentleness with the self.
The elimination of cruelty towards animals would seem to me to be only achievable after the elimination of cruelty towards the self, and cruelty towards other human beings, particularly children -- thus I think that the goals of this philosophy conversation arenecessary prerequisites for the goals of animal rights activists, and so I am sure that we can work together to achieve the necessary empathy within the human race that serve both of our goals of elevating the moral sentiments of mankind.