 Davidson additionally claims that the relation between the mental and physical properties is not merely haphazard or coincidental. A relationship of supervenience obtains between the two (Davidson 1970, 214; 1973a, 253; 1993; 1995a, 266). (Davidson never argues for supervenience. For discussion, see the supplement on  Supervenience and the Explanatory Primacy of the Physical.)  A working statement of this relationship is that if two events fail to share a mental property, they will fail to share at least one physical property (Davidson 1995a, 266)—or, equivalently, if two events share all of their physical properties, they will share all of their mental properties. It is meant to articulate a kind of dependency of the mental on the physical, and correlatively a kind of explanatory primacy to the physical, but without claiming any kind of reductive relation between the mental and the physical. The working statement’s truth depends, it seems, on the thought that the distribution of physical properties somehow explains the distribution of mental properties—failure to share a mental property depends upon/is explained by failure to share at least one physical property. The supervenience relation is usually understood to issue in generalizations of the following kind: ‘P1 → M1’, ‘P2 → M1’, etc. (where antecedent and consequent occur at the same time). This allows for the empirical possibility that a number of different physical state kinds underlie the same mental state kind (for more on this, see the supplement on  Related Issues  (Mental Anomalism and Semantic Externalism)). However, it also appears to suggest the existence of lawlike relations between physical and mental properties, and so to be in tension with mental anomalism. This issue will be explored in  5.3.