Belief in belief is a situation where a model of the world you claim and believe to have is at odds with a model of the world that explains your actions and drives your anticipation of experience. You are always ready to provide an excuse for the next experiment not supporting your stated belief, because you know the outcome of the experiment in advance, but have to rationalize it in terms of the stated belief. Belief in belief can be seen as a form of compartmentalization, which protects your actual model of the world from insane memes that survive as stated beliefs. Were you to really believe and not just believe in belief, the consequences of error would be much more severe.
Related tags: Belief, Alief, Self-deception