The final part focusses on the concepts of positive and negative liberty first described in the 1950s by Isaiah Berlin. Curtis briefly explains how negative liberty could be defined as freedom from coercion and positive liberty as the opportunity to strive to fulfill one's potential. Tony Blair had read Berlin's essays on the topic and wrote to him in the late 1990s, arguing that positive and negative liberty could be mutually compatible. As Berlin was on his deathbed at the time, Blair never got a reply.