APODICTIC KNOWLEDGE (also “apodeictic”)—one of the types of human knowledge characterized by evidence and certainty, occurring mainly in Aristotle’s conception of science; the source of its evidence and certainty is the certainty of its premises.

The task of apodictic knowledge is to present the structure of reality by showing its ultimate causes, which in a system of knowledge correspond to the most general conceptions, and to provide assertions that subordinate reality to these most general causes.

Apodictic knowledge is opposed under the aspect of evidence and certainty to dialectical knowledge which begins from uncertain and non-evident premises (dialectics here is understood differently that in Plato—as the knowledge possessed by a skilfull speaker who is trying to convince others of his statements).

The conception of apodictic knowledge is presented in Aristotle’s Posterior Analytics. Apodictic knowledge is composed of two kinds of elements: definitions and assertions. Definitions (these are real definitions) present the essence of objects studied, while assertions present the connections between these objects. These definitions and assertions create a system such that the definitions define terms with the help of more primary terms, and assertions are justified by assertions that have been justified earlier: at the foundations of the series of definitions and of the series of assertions there are primary (indefinable) terms and ultimate assertions (μ)—these are the ultimate premises of science. The mind arrives at them by induction but grasps them by intellectual intuition which directly provides knowledge of the essence of the thing designated by the primitive terms and directly provides an affirmation of the evident truth of ultimate assertions. Primary terms have as their object the most general genera, while axioms are the most general assertions; both are simplest in their kind and that is how Aristotle explains their evidence; the mind comes upon them in a necessary way (often today there is another view of this). This is a consequence of Aristotle’s realistic position. According to Aristotle the aim of science is to have an adequate understanding of objective reality. Postulates (μ) are a third kind of presupposition of apodictic knowledge, besides axioms and primary terms. Postulates are hypothetical suppositions that enter in the course of a demonstration (they are the predecessors of assertions of a necessary form)— of themselves hypothetical suppositions do not create scientific assertions.

T. Czeżowski, Logika [Logic], Wwa 1949, 1965²; Aristotle, Analytiki drugie [Posterior Analytics], in: idem, Dzieła wszystkie [Complete works], I, Wwa 1990.

Marek Lechniak

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