 The slogan “There cannot be an A-difference without a B-difference” is applied both to particular individuals and to entire possible worlds. In the former case, the slogan expresses the idea that two individuals cannot differ in A-respects without also differing in B-respects. This sort of claim is an individual supervenience claim. In the latter case, the slogan expresses the idea that two possible worlds cannot differ with respect to their world-wide pattern of distribution of A-properties without also differing with respect to their world-wide pattern of distribution of B-properties. That sort of claim is a global supervenience claim. Both individual and global supervenience claims come in a variety of modal strengths. In this section, we will distinguish various forms of both individual and global supervenience, and examine some logical relationships among them.