Schumpeter's vast erudition is apparent in his posthumous History of Economic Analysis, although some of his judgments seem quite idiosyncratic and sometimes cavalier. For instance, Schumpeter thought that the greatest 18th century economist was Turgot, not Adam Smith, as many consider. Some of these judgments are partly explained by his opinion that there is one general system of economic analysis, and Léon Walras found it. Other economists are rated by how much of Walras' theory could be read into them. Schumpeter criticized John Maynard Keynes and David Ricardo for the "Ricardian vice." According to Schumpeter, Ricardo and Keynes reasoned in terms of abstract models, where they would freeze all but a few variables. Then they could argue that one caused the other in a simple monotonic fashion. This led to the belief that one could easily deduce policy conclusions directly from a highly abstract theoretical model.