"Apodictic", also spelled "apodeictic" (Ancient Greek: ἀποδεικτικός, "capable of demonstration"), is an adjectival expression from Aristotelean logic that refers to propositions that are demonstrably, necessarily or self-evidently true.
[1] Apodicticity or apodixis is the corresponding abstract noun, referring to logical certainty.
For instance, "Three plus one equals four" is apodictic, because it is true by definition.
In Aristotelian logic, "apodictic" is opposed to "dialectic", as scientific proof is opposed to philosophical reasoning.
Kant contrasted "apodictic" with "problematic" and "assertoric" in the Critique of Pure Reason, on page A70/B95.