This slogan is introduced to the reader in Book I Chapter 1 of this novel, and as it is introduced so early on, it can be seen as being key to understanding the principles under which the Party operates and in particular the key concept of doublethink. This is apparent from the simple but subvertive way in which the slogan is presented:
WAR IS PEACE
FREEDOM IS SLAVERY
IGNORANCE IS STRENGTH
As the novel develops, it is clear that the Party's first and most important job is to attack and destroy the capacity of individuals to make their own decisions and to trust in their own intelligence and common sense. The result of this is that the populace are able to accept whatever the Party says, even if it is entirely paradoxical, as the statements suggest. This principle of doublethink that is introduced so early in the novel through this slogan is shown to be supported through the tasks of the various ministries; the Ministry of Truth, for example, has the job of presenting the Party's version of events as if it were truth, even though within him Winston Smith acknowledges they are lies. The paradoxical nature of this slogan therefore reveals the role propaganda has in maintaining the Party's absolute totalitarian regime: in spite of its paradoxical nature, there is an element of truth in "Ignorance is Strength," because it is through the ignorance of the people that the Party maintains its iron-grip of power over Oceania.