How do we know when something has a mind? We're fairly certain that rocks and beer cans don't, of course, and most of us are also convinced that we ourselves have minds—but what about the gray areas? Do robots or frogs or kittens or human embryos have minds? What about people who have such severe brain damage that they are hospitalized in persistent vegetative states? Questions like these can be puzzling to philosophers, but they are answered in a practical sense every day as we each perceive minds in some things, and not in others. The study of mind perception asks how we make this important determination, how we empathize with each other, how we distinquish mental events from physical events, and much more.