To Namier it had seemed obvious that political theories act as the merest ex post facto rationalisations of political behaviour. If we are looking for explanations of political action, he maintained, we must seek them at the level of ‘the underlying emotions, the music, to which ideas are a mere libretto, often of very inferior quality'. For critics of Namier such as Sir Herbert Butterfield, the only possible retort seemed to be to go back to a famous dictum of Lord Acton's to the effect that ideas are often the causes rather than the effects of public events. But this response duly incurred the scorn of Namier and his followers for the alleged naiveté of supposing that political actions are ever genuinely motivated by the principles used to rationalise them.