Abstract
As Raymond Martin noted, historians can make objective judgments about relative causal importance. He constructs a philosophical statement showing that counterfactuals enable us to assess relative causal importance. To justify the counterfactual statement itself, historians usually intuitively try to find for a comparison some other real situation which is in some important respect similar to the possible situation reflected in the counterfactual claim. The question then becomes, "How do we know that the actual historical situation, the counterfactual situations, and the real comparison situations are similar in relevant aspects?" As Martin did, we must look at real cases of historical thinking to make a philosophical statement, which in turn leads to a new set of questions and so on. At some stage a statement that gives substantial support to the Marxist claim that history is a scientifically analyzable, law-governed process will be reached