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.

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.

An animal experiment cannot be justifiable unless the experiment is so important that the use of a brain-damaged human would be justifiable.

There could conceivably be circumstances in which an experiment on an animal stands to reduce suffering so much that it would be permissible to carry it out even if it involved harm to the animal... [even if] the animal were a human being.

Evolution has no moral direction. An evolutionary understanding of human nature can explain the differing intuitions we have when we are faced with an individual rather than with a mass of people, or with people close to us rather than with those far away, but it does not justify those feelings.

I believe that in this new world that we live in, we often have a responsibility, you know, to actually go beyond the thou shalt nots - that is, the not harming others - and say we can help others and we should be helping others.

Sometimes we know the best thing to do, but fail to do it. New year's resolutions are often like that. We make resolutions because we know it would be better for us to lose weight, or get fit, or spend more time with our children. The problem is that a resolution is generally easier to break than it is to keep.