"How could anyone seriously believe that animals do not feel pain? After all, we have virtually the same evidence for animal pain that we have for human pain......So, on what grounds could anyone possible say animals are insensitive to pain?"

“The doctrine of human dignity says that humans merit a level of moral concern wholly different from that accorded to mere animals; for this to be true, there would have to be some big, morally significant difference between them. Therefore, any adequate defense of human dignity would require some conception of human beings as radically different from other animals. But that is precisely what evolutionary theory calls into question. It makes us suspicious of any doctrine that sees large gaps of any sort between humans and all other creatures. This being so, a Darwinian may conclude that a successful defense of human dignity is most unlikely.”

“Human life will no longer be regarded with the kind of superstitious awe which it is accorded in traditional thought, and the lives of non-humans will no longer be a matter of indifference. This means that human life will, in a sense, be devalued, while the value granted to non-human life will be increased. A revised view of such matters as suicide and euthanasia, as well as a revised view of how we should treat animals, will result.”

“Ethical Egoism advocates that each of us divide the world into two categories of people—ourselves and all the rest—and that we regard the interests of those in the first group as more important than the interests of those in the second group. But each of us can ask, what is the difference between myself and others that justifies placing myself in this special category? Am I more intelligent? Do I enjoy my life more? Are my accomplishments greater? Do I have needs or abilities that are so different from the needs and abilities of others? What is it that makes me so special? Failing an answer, it turns out that Ethical Egoism is an arbitrary doctrine, in the same way that racism is arbitrary.”

“Our triumphs seem hollow unless we have friends to share them, and our failures are made bearable by their understanding.”

“We should care about the interests of other people for the same reason we care about our own interests; for their needs and desires are comparable to our own.”

“Official website of James Rachels”