What is Judaism? A religion? A faith? A way of life? A set of beliefs? A collection of commands? A culture? A civilization? It is all these, but it is emphatically something more. It is a way of thinking about life, a constellation of ideas. One might think that the ideas Judaism introduced into the world have become part of the common intellectual heritage of humankind, at least of the West. Yet this is not the case. Some of them have been lost over...