The Psychology of Certainty explores how seemingly rigid beliefs are often defensive responses to unprocessed fear, shame, and grief. The central argument is that when people feel overwhelmed or their core identity is threatened, they retreat into simplified worldviews to maintain a sense of order and emotional safety, often leading to an intolerance for nuance or contradiction. We examine how this phenomenon, which is amplified in polarized times, transforms emotional protection into intellectual armor and moral superiority, highlighting that what appears as certainty is often a mask for psychological fragility. Ultimately, suggesting that moving beyond this destructive rigidity requires engaging with deeper emotional truths and choosing love and conscience over the desperate need to be right.