apodeictic

Affording proof; demonstrative.

Incontrovertible; demonstrably true or certain.

Of the characteristic feature of a proposition that is necessary (or impossible): perfectly certain (or inconceivable) or incontrovertibly true (or false); self-evident.

1855, John Miller Dow Meiklejohn (translator), 1787, Immanuel Kant, Critique of Pure Reason, 2nd Edition, Thus, moreover, the principles of geometry- for example, that "in a triangle, two sides together are greater than the third," are never deduced from general conceptions of line and triangle, but from intuition, and this a priori, with apodeictic certainty.

Aristotle does, indeed, distinguish between (1) Logic, or Analytic, as the theory or method of arriving at true or apodeictic conclusions; and (2) Dialectic as the method of arriving at conclusions that are accepted or pass current[ly] as true,...