We all do it. In fact, we are generally very good at it. Smart and educated people are better at it.
Rationalizing is a daily practice, part of the “default mode” of human thinking. We make up reasons to justify believing what we want to believe. Often we are only dimly aware of why we want to believe something, the calculus largely occurring in the subconscious depths of our brains.
We defend beliefs because they are pleasing to our egos, because they minimize cognitive dissonance, and just because they are our beliefs. They resonate with our world-view, our internal model of reality.
We have at our disposal a long list of logical fallacies that we can marshal to the defense of our beliefs. Notions that are based on solid evidence and logic do not require such vigorous defense. Those beliefs that cannot be defended by logic and evidence require that bad logic and bad data be invoked to defend them. Luckily we have no problem distorting and cherry picking facts and twisting logic into pretzels.
One very common bit of bad logic is called special pleading. I think it is common because it is so insidious – it creeps up on us unaware. Special pleading is the process of inventing a special reason to explain away inconvenient evidence or the lack of predicted evidence.
Take, for example, ESP research.
Keep reading: NeuroLogica Blog » ESP Special Pleading.