Suppose I grant that pigs and dogs are self-aware to some degree, and do have thoughts about things in the future. That would provide some reason for thinking it intrinsically wrong to kill them - not absolutely wrong, but perhaps quite a serious wrong. Still, there are other animals - chickens maybe, or fish - who can feel pain but don't have any self-awareness or capacity for thinking about the future. For those animals, you haven't given me any reason why painless killing would be wrong, if other animals take their place and lead an equally good life.

Forests and meat animals compete for the same land. The prodigious appetite of the affluent nations for meat means that agribusiness can pay more than those who want to preserve or restore the forest. We are, quite literally, gambling with the future of our planet – for the sake of hamburgers

Marx saw that capitalism is a wasteful, irrational system, a system which controls us when we should be controlling it. That insight is still valid; but we can now see that the construction of a free and equal society is a more difficult task than Marx realized.

I know of a number of people who are successfully earning to give. That isn't for everyone but for those with the ability to earn a lot of money and the character to resist the temptation to spend it on themselves, it can be a great way to do good.

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.

It is easy for us to criticize the prejudices of our grandfathers, from which our fathers freed themselves. It is more difficult to distance ourselves from our own views, so that we can dispassionately search for prejudices among the beliefs and values we hold

If you have the abilities to earn a lot of money and if you have the character to persist in giving that to the most effective charities you can find, then that may be the best thing that you can do. And - also, if you do become a Wall Street banker, I think you need to be aware of what you're doing in terms of your daily work, not just earning money to give a lot away. But you need to think about - am I harming people through the work that I'm doing?