Constant conjunctions are best analysed in terms of sufficient and necessary conditions. Once regularities have thus been classified, then as a further step we can bring out causal links, or give a description in terms of causes. The steam roller example is in fact an example of causation. They are reinterpretations of Mill s methods as criteria for determining such conditions. The treatment of Mill s methods is thus logically reconstructed and simplified, but becomes fairly dry.
E is called the conditioned property.
We can now distinguish the different methods. A, B, C, D are present or absent. Occurrences in which one or more of A, B, C or D are absent rule out such conditions as possible necessary conditions. Hence this criterion is called the direct method of agreement . Now we are looking for sufficient conditions, and it is the conditioning properties that are present in the various occurrences which are being eliminated.