The use of the term “slavery” in relation to something that it is wrong to do to animals is especially significant, for until now it has been assumed that animals are rightly our slaves, to use as we wish, whether to pull our carts, be models of human diseases for research, or produce eggs, milk, or flesh for us to eat. Recognition by a government that it can be wrong to enslave animals is a significant breach in the wall of exclusive moral significance we have built around our own species.