"Tigers lead solitary lives, except for mothers with their cubs. We, by contrast, are social animals. So are elephants, and elephant mothers do not focus only on the wellbeing of their own offspring. When it comes to raising our children, we need fewer tigers and more elephants."
"All the arguments to prove man's superiority cannot shatter this hard fact: in suffering the animals are our equals."
"As we realise that more and more things have global impact, I think we're going to get people increasingly wanting to get away from a purely national interest."
"There is only one place for any fur coat, and that is on the back of an animal."
"The problem is not with the athletes, but with us. No matter how blatant the drug use may be, we don't stop watching the Tour de France. Maybe we should just turn off the television and get on our own bikes."
"At the descriptive level, certainly, you would expect different cultures to develop different sorts of ethics and obviously they have; that doesn't mean that you can't think of overarching ethical principles you would want people to follow in all kinds of places."
"We need to get over our reluctance to speak openly about the good we do. Silent giving will not change a culture that deems it sensible to spend all your money on yourself and your family, rather than help those in greater need - even though helping others is likely to bring more fulfilment in the long run."
"In a sense, human nature doesn't change much, but I think there are some factors that might be making it more ethical."
"In a situation where many national leaders do the same thing and look out for national interests, and with an issue like global warming, you're likely to get no solution, so I think you have to have some kind of ethical trump on some of those issues."
"Why are fish the forgotten victims on our plate? Is it because they are cold-blooded and covered in scales? Is it because they cannot give voice to their pain? Whatever the explanation, the evidence is now accumulating that commercial fishing inflicts and unimaginable amount of pain and suffering."
"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."
"An animal experiment cannot be justifiable unless the experiment is so important that the use of a brain-damaged human would be justifiable."