- Date: 14th century
- 1 : something that is certain
- 2 : the quality or state of being certain especially on the basis of evidence
certitude, conviction mean a state of being free from doubt. certainty and certitude are very close; certainty may stress the existence of objective proof <claims that cannot be confirmed with scientific certainty>, while certitude may emphasize a faith in something not needing or not capable of proof <believes with certitude in an afterlife>. conviction applies especially to belief strongly held by an individual <holds firm convictions on every issue>.
Certainty can be defined as either (a) perfect knowledge that has total security from error, or (b) the mental state of being without doubt. Objectively defined, certainty is total continuity and validity of all foundational inquiry, to the highest degree of precision. Something is certain only if no skepticism can occur.