"Apodictic" or "apodeictic" (Ancient Greek: "ἀποδεικτικός," "capable of demonstration") is an adjectival expression from Aristotelean logic that refers to propositions that are demonstrable, that are necessarily or self-evidently the case or that, conversely, are impossible. Apodicticity is the corresponding abstract noun, referring to logical certainty.
Apodictic propositions contrast with assertoric propositions, which merely assert that something is (or is not) the case, and with problematic propositions, which assert only the possibility of something being true. For instance, "Two plus two equals four" is apodictic. "Chicago is larger than Omaha" is assertoric. "A corporation could be wealthier than a country" is problematic. In Aristotelian logic, "apodictic" is opposed to "dialectic," as scientific proof is opposed to probable reasoning. Kant contrasts "apodictic" with "problematic" and "assertoric" in the Critique of Pure Reason, page A70/B95.
The expression "apodictic" is also sometimes applied to a style of argumentation in which a person presents his reasoning as being categorically true, even if it is not necessarily so. An example of such a usage might be: "Demonstrate less apodicticity! You haven't considered several facets of the question."