Rational Emotive Behaviour Therapy (REBT) therapists facilitate client intellectual insight by soliciting and responding to clients' doubts, reservations and objections to the principles and practices of REBT. Clients may argue that REBT can only be applied to relatively insignificant matters in life and that flexible and non-extreme thinking cannot be applied to very important adversities. When clients first encounter irrational attitudes and rational attitudes, they often think that some irrational attitudes are in fact positive and some rational attitudes are negative. Once clients' doubts have been dealt with, REBT therapists teach them to understand the difference between intellectual insight and emotional change. Emotional change was initially discussed by Ellis and, along with behavioural change, is one of the true goals of REBT. Intellectual insight is enhanced by reading books on REBT or listening to audio and video presentations like those theory and practice of REBT while emotional change cannot be achieved in this passive way.