A class ideology was inevitably relative and contingent: subjectively biased by the perspective from which the world was viewed, and objectively limited by the limitations of social and historical experience of the epoch. But in the sense of a mechanical determinism, in which human activity can make no difference to the final outcome, the term has certainly no application to historical materialism. That historical materialism originated in antithesis to the view that history is to be interpreted in terms of the self-development of ideas is probably too familiar to need much emphasis. What a leading economic historian of our day has said of the rationalist’s approach to history could be said also, mutatis mutandis, of the historical materialist’s: He cannot be accused of trying to solve by syllogism or by laboratory experiment every problem of the universe and to base on them every rule of conduct.