 Thus if it is a statistical law that the probability of recovery from streptococcus, given that one has taken penicillin, is high, and Jones has taken penicillin and recovered, this information can be used to provide an IS explanation of Jones’s recovery. However if the probability of recovery is low (e.g., less than 0.5), given that Jones has taken penicillin, then, even if Jones recovers, we cannot use this information to provide an IS explanation of his recovery.