You might hold an ethical position that its wrong to lie, but if you have plans for a war in Iraq, and you want to keep them secret for practical reasons – to reduce casualties, perhaps – and someone asks you about those plans, you may need to lie for a good outcome. – Peter Singer
Thats 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. – Peter Singer