My work is based on the assumption that clarity and consistency in our moral thinking is likely, in the long run, to lead us to hold better views on ethical issues.

Were we incapable of empathy – of putting ourselves in the position of others and seeing that their suffering is like our own – then ethical reasoning would lead nowhere. If emotion without reason is blind, then reason without emotion is impotent.

If possessing a higher degree of intelligence does not entitle one human to use another for his or her own ends, how can it entitle humans to exploit non-humans?

In the sense that you're not at the centre of power, like a president or prime minister of a major power, everyone is marginalised; my position doesn't isn't unique in that respect. I think there are different sorts of relevance in different contexts.

If you're buying animal products and can go to the farm and actually see how the animals are looked after, yes, that's an important point. That's definitely the best way of assuring yourself that the animals are being well treated.

If we are concerned about the exploitation of human workers in countries with low standards of worker protection, we should also be concerned about the treatment of even more defenceless non-human animals.

Why...is the hunter who shoots a deer for venison subject to more criticism than the person who buys a ham at the supermarket? Overall, it is probably the intensively reared pig who has suffered more.