The feeling of Certainty can be triggered without the need for facts or reasoning, using electric stimulation over a specific part of the brain.
Being certain is a revolutionary look at how we know what we know. At stake is the commonly held belief that we can logically and reasonably determine when our thoughts are correct.
If, after due rumination and deliberation, we decide that thought must be correct, we presume that this conclusion is itself a conscious choice. On being certain presents compelling evidence that this assumption is inconsistent with the present-day understanding of basic brain function. Drawing from case studies and recent neuroscience advances, as well as such far-ranging subject material as the physics of baseball, high-stakes poker, and popular discussions of gut feelings and the nature of intuition, On being certain systematically undermines certainty and conviction as products of reason.
Despite how certainty feels, it is neither a conscious choice nor even a thought process. Certainty and similar states of "knowing what we know" are sensations that feel like thoughts, but arise out of involuntary brain mechanisms that function independently of reason.