If you go back in time you'll find tribes that were essentially only concerned with their own tribal members. If you were a member of another tribe, you could be killed with impunity.

To be a utilitarian means that you judge actions as right or wrong in accordance with whether they have good consequences. So you try to do what will have the best consequences for all of those affected.

Grain that is used to feed animals that end up on our tables as turkeys and hams could have gone to feed starving people.

If we all think only of our own interests, we are headed for collective disaster - just look at what we are doing to our planet's climate.

I don't think there's much point in bemoaning the state of the world unless there's some way you can think of to improve it. Otherwise, don't bother writing a book; go and find a tropical island and lie in the sun.

Animal factories are one more sign of the extent to which our technological capacities have advanced faster than our ethics.

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.