Overview
Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, and is uncertain about them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty, distrust or lack of conviction on certain facts, actions, motives, or decisions. Doubt can result in delaying or rejecting relevant action out of concern for mistakes or missed opportunities.
Psychology
Partial or intermittent negative reinforcement can create an effective climate of fear and doubt.
Philosophy
Descartes employed Cartesian doubt as a pre-eminent methodological tool in his fundamental philosophical investigations. Branches of philosophy like logic devote much effort to distinguish the dubious, the probable and the certain. Much of illogic rests on dubious assumptions, dubious data or dubious conclusions, with rhetoric, whitewashing, and deception playing their accustomed roles.
Theology
From Wikipedia (CC BY-SA 4.0).