Cheats prosper until there are enough who bear grudges against them to make sure they do not prosper.

My aim is to advocate that we make this mental switch in respect of our attitudes and practices towards a very large group of beings: members of species other than our own - or, as we popularly though misleadingly call them, animals. In other words, I am urging that we extend to other species the basic principle of equality that most of us recognize should be extended to all members of our own species.

Even in the era of AIDS, sex raises no unique moral issues at all. Decisions about sex may involve considerations about honesty, concern for others, prudence, and so on, but there is nothing special about sex in this respect, for the same could be said of decisions about driving a car. (In fact, the moral issues raised by driving a car, both from an environmental and from a safety point of view, are much more serious than those raised by sex.)

If you're buying animal products and can go to the farm and actually see how the animals are looked after, yes, that's an important point. That's definitely the best way of assuring yourself that the animals are being well treated.

I honestly don't know, but if America continues to refuse to reduce its greenhouse gas emissions, I see a bleak future not only for American society, but for the world as a whole. This is a global problem that is not going away, and the United States is an obstacle to solving it.

There is a growing movement called effective altruism. It's important because it combines both the heart and the head.

If we are concerned about the exploitation of human workers in countries with low standards of worker protection, we should also be concerned about the treatment of even more defenceless non-human animals.