Becoming a vegetarian is not merely a symbolic gesture. Nor is it an attempt to isolate oneself from the ugly realities of the world, to keep oneself pure and so without responsibility for the cruelty and carnage all around. Becoming a vegetarian is a highly practical and effective step one can take toward ending both the killing of nonhuman animals and the infliction of suffering on them.

That's a central part of philosophy, of ethics. What do I owe to strangers? What do I owe to my family? What is it to live a good life? Those are questions which we face as individuals.

Today, if you have an Internet connection, you have at your fingertips an amount of information previously available only to those with access to the world's greatest libraries - indeed, in most respects what is available through the Internet dwarfs those libraries, and it is incomparably easier to find what you need.

Can we really believe that we are living a good life, an ethically decent life if we don't do anything serious to help reduce poverty around the world and help save the lives of children or adults who are likely to die if we don't increase the amount of aid we are giving.

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.

As for cages themselves, an ordinary citizen who kept dogs in similar conditions for their entire lives would risk prosecution for cruelty. A pig producer who keeps an animal of comparable intelligence in this manner, however, is more likely to be rewarded with a tax concession or, in some countries, a direct government subsidy.

The future of the world depends on how well we meet it.