...the nervous systems of other animals were not artificially constructed - as a robot might be artificially constructed - to mimic the pain behavior of humans. A capacity to feel pain obviously enhances a species' prospects of survival...it is surely unreasonable to suppose that nervous systems that are virtually identical physiologically, have a common origin and a common evolutionary function, and result in similar forms of behavior in similar circumstances should actually operate in an entirely different manner on the level of subjective feelings.

So why don't we make ourselves the last generation on earth? If we would all agree to have ourselves sterilized then no sacrifices would be required - we could party our way into extinction!

Somebody who eats twice as much factory-farmed products as he or she needs to is clearly doing twice as much damage to the planet. From a utilitarian point of view, that's twice as bad.

Lay off with the 'You reason, so you don't feel' stuff, please. I feel, but I also think about what I feel. When people say we should only feel I am reminded of Göring, who said 'I think with my blood.' See where it led him.

But I think the majority of cows, and even more so chickens and pigs, are leading pretty miserable lives.

If we compare a severely defective human infant with a nonhuman animal, a dog or a pig, for example, we will often find the nonhuman to have superior capacities, both actual and potential, for rationality, self-consciousness, communication and anything else that can plausibly be considered morally significant.

The animal liberation movement is saying that where animals and humans have similar interests - we might take the interest in avoiding physical pain as an example, for it is an interest that humans clearly share with other animals - those interests are to be counted equally, with no automatic discount just because one of the beings is not human.