ience as "B-properties supervene on A-properties if no two possible situations are identical with respect to their A-properties while differing in their B-properties" (Chalmers 33). The notion of supervenience is meant to capture our belief that in processes such as life, higher level properties of organisms (e.g., size, shape, and behavior) really depend upon and can be explained by much lower level properties (such as genes, DNA, nerve impulses, etc.). This rather simple notion of supervenience can be divided into many highly technical sub-categories, each with slightly different interpretations and meanings. For the purposes of this paper, a grasp of the differences between logical, metaphysical, and natural supervenience will be sufficient to understand the arguments put forth by materialists, property dualists, and eliminativists. Logical supervenience can be characterized by the claim: B-properties supervene logically on A-properties if it is logically impossible for two situations to have exactly the same B-properties without also sharing the same A-properties. Another way of thinking about this is to consider what it would be in God's power to create. It would be impossible for God to create a world in which, for example, bachelors were married. Due to the meanings of those two terms, it is logically impossible for a bachelor to be married. Therefore, bachelorhood logically supervenes on a man's marital status. However, it does seem possible that God could have made a world in which the ideal gas laws did not hold.(1) This certainly could not happen in our world, but if God were to change a few of the laws of physics, the ideal gas law could also change. This brings us to the notion of natural (or nomic) supervenience. Chalmers describes natural supervenience as the result of two sets of properties being "systematically and perfectly correlated in the natural world" (Chalmers 36). Formally, the concept of natural supervenience i...
