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.

There is an obvious evolutionary explanation for the scarcity of altruistic saints: Without a strong predilection for their own interests, our ancestors would have been unlikely to survive, reproduce, and give their own offspring a chance of doing the same. Now conditions have changed and for most of us, surviving and reproducing isn't such a struggle but we still carry the genes of our ancestors and they influence - not determine, but influence - our behavior.

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.

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.

It is an indication of the extent to which people are now isolated from the animals they eat that children brought up on storybooks that lead them to think of a farm as a place where animals wander around freely in idyllic conditions might be able to live out their entire lives without ever being forced to revise this rosy image.

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.

Cheats prosper until there are enough who bear grudges against them to make sure they do not prosper.