 Berlin’s writings on political judgement, activity and leadership are of a piece with his larger epistemological project: to bring to light the tension between abstract or a priori theory and direct perception; and to warn against the dangers of the former and assert the importance of the latter. While he acknowledged that it was impossible to think without the use of analogies and metaphors, that thought necessarily involves generalisation and comparison, he warned that it was important to be cautious, self-conscious and critical in the use of general models and analogies (see 1978b, 207–8). These writings also reassert the message of the youthful essay ‘Some Procrustations’ (1930, discussed in 4.3 above): that the same rules should not be automatically applied to every facet of human life. Rationality consists of the application, not of a single technique or set of rules, but of those methods that have proven to work best in each particular field or situation. This view of political judgement also relates to Berlin’s attempt to vindicate the importance of individual agency and personality, by insisting that political judgement is a personal quality, and effective political activity a matter of personal consideration, decision and action rather than (or at least in addition to) impersonal administration or the deployment of institutional machinery.