There are few more unsettling philosophical questions than this: What happens in attempts to reduce some properties to some other more fundamental properties? Reflection on this question inevitably touches on very deep issues about ourselves, our own interactions with the world and each other, and our very understanding of what there is and what goes on around us. If we cannot command a clear view of these deep issues, then very many other debates in contemporary philosophy seem to lose traction - think of causation, laws of nature, explanation, consciousness, personal identity,...