"As many of Keynes' disciples would now admit, his theories had two important weaknesses when applied in postwar Britain. They ignored the economic impact of social institutions, particularly the trade unions; in fact Keynesian policies were unlikely to work in Britain without strict control of incomes... And they ignored the outside world... [T]he fundamental Keynesian concept of demand management had become unreliable. Keynes believed that a government could maintain full employment of a country's productive capacity without creating inflation, by increasing or reducing the demand for its output, through adjusting taxes or government spending. But it had become impossible to discover with any accuracy how much additional demand the government should inject into the economy so as to produce full employment... Keynes was right in saying that adequate demand is a necessary condition for full employment; but, given the inadequacy of the information available and the uncertainty about how people will use their money, fine tuning of demand is not possible."