 To employ one of Salmon’s examples, suppose we want to construct an SR explanation of why x who has a strep infection = S, recovers quickly = Q. Let \(T(-T)\) according to whether x is (is not) treated with penicillin, and \(R(-R)\) = according to whether x has a penicillin-resistant strain. Assume for the sake of argument that no other factors are relevant to quick recovery. There are four possible combinations of these properties: \(T.R,\) \(-T.R,\) \(T.{-R},\) \({-T}.{-R},\) but let us assume that