Lewis: Those who do not learn from past mistakes -- their own and those of others -- are condemned to repeat them. In order to benefit from the lessons of history, however, we first have to know history. That is why the acquisition of broad historical knowledge is so important. Morris: The trouble is that the past is infinitely various. From its inexhaustible storehouse of events it is possible to prove anything or its contrary. The issue that Morris raises in objecting to Lewis' view is whether ['historical knowledge can be too narrow to be useful', 'there are conventional criteria for calling a past action a mistake', 'history teaches any unequivocal lessons', 'there are any uncontested historical facts']