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.

History is not going to look kindly on us if we just keep our head in the sand on armed autonomous robotics issue because it sounds too science fiction.

At present scientists do not look for alternatives simply because they do not care enough about the animals they are using.

Remember that not everyone is as strong as you are. Be mindful of human weakness, and of the fact that it may be more important, in the long run, to get many people taking steps in the right direction than to have fewer achieving the ideal.

If zoos are like arks, then rare animals are like passengers on a voyage of the damned, never to find a port that will let them dock or a land in which they can live in peace. The real solution, of course, is to preserve the wild nature that created these animals and has the power to sustain them. But if it is really true that we are inevitably moving towards a world in which mountain gorillas can survive only in zoos, then we must ask whether it is really better for them to live in artificial environments of our design than not to be born at all.

Looking back on my career, I think I've been extremely fortunate to be in the right place at the right time in order to have the influence that I did.

If you earn a lot of money, you can give away a lot of money.