In a free society the purpose of mass surveillance should be to protect the way we live

Surveillance is not an end in itself. It has a purpose. In a free society the purpose of surveillance should be to protect the way we live, including our privacy, our liberty, and our democracy; and to frustrate those that want to take these things away. But mass surveillance that infringes on privacy and liberty fails to play this role and consequently undermines the way we live, writes Mark Harrison.