Certainty is based on one’s current knowledge. It is possible to be certain, and still be wrong. Certainty is the acceptance of a fact without doubt. It is a level of confidence attributed to particular knowledge. Certainty could have no meaning when applied to an omniscient being, since it wouldn’t have the capacity for doubt. It is often used to describe knowledge without the possibility of doubt. Certainty equivalent is a guaranteed return that someone would accept, rather than taking a chance on a higher, but uncertain, return.
