Duhem attempted to find a middle way between two positions he regarded as extremes, the conventionalism of Poincaré and the scientific realism of the majority of his scientific colleagues. He argued that conventionalism exaggerated the arbitrariness of scientific formulations, but that belief in atoms and electrons erred in the opposite direction by attributing too much logical force to explanatory theories. The instrumentalist sympathies so apparent in Duhem's writings on the history of astronomy are only partially counterbalanced by his view that science is progressing toward a ‘natural classification’ of the world.