 There has not been any historical trend discernible as an evolution of the doctrine of logicism, with incremental adjustments to deal with occasional problems as they arose, while maintaining a reasonably stable trajectory towards an ideal formulation. Rather, the doctrine has been characterized by abrupt shifts as far as methods and materials are concerned, even if the goal has remained relatively constant through such  changes.[2]  We shall allow the pattern of change to become evident as the different phases of logicism are recounted below. 