 Note that the specification of factors that need to be held fixed appeals to causal relations, so the theory no longer offers a reductive analysis of causation. Nonetheless, the theory imposes probabilistic constraints upon possible causal relations in the sense that a given set of probability relations will be incompatible with at least some systems of causal relations. Note also that we have dropped the subscripts referring to times. Cartwright claimed that it is not necessary to appeal to the time order of events to distinguish causes from effects in her theory. That is because it will no longer be true in general that if C raises the probability of E in every relevant background context B, then E raise will raise the probability of C in every background context \(B'\). The reason is that the construction of the background contexts ensures that the background contexts relevant to assessing C’s causal relevance for E are different from those relevant to assessing E’s causal relevance for C. However, Davis (1988) and Eells (1991) both argue cogently that Cartwright’s account will still sometimes rule that effects bring about their causes.