For the Aristotelian version of rationality, knowledge does not aim at closure and completion, at the construction of an authentic description of the world. The Greek philosopher does not embrace the modern belief that language-knowledge can depict with absolute precision the cosmic, social, and psychological reality, and interpret it in the fullness of its depth.

His theoretical practice is grounded in the belief that the indeterminate exists precisely as such, that every rational cognitive determination leaves an undefined and irrational residue, that necessity and contingency are intertwined, and that the soul always remains other than what logical clarity delineates as the soul.

Within Aristotle's philosophy emerges his critical rational theory of knowledge; the core of its criteria is not syntactical but social-political. Logic is primarily the ability to communicate the meaning of the statement, to function as a common discourse.

Knowledge can only be validated a posteriori, as a social fact of the response of abstract formulations to the experience of recipients. Thus, Aristotle's theory of the soul remains rationally scientific, without envying the absolute precision of a conceptual edifice, without being bound by insurmountable axiomatic principles, without hunting for the internal consistency of a self-sustaining system.

Aristotle relativizes closed constructions and mechanistic interpretations; he subverts any certainties imposed by his teaching, refusing to substitute the truth of things with its formulation.

He does not consider logical proof as the exclusive method of producing knowledge; he integrates it into that cognitive act which activates the entire human existence rooted in the world and society. This pragmatic knowledge is indeed existential knowledge. Aristotle's apophatic rationalism moves towards the antipodes of rationalism: simply in life.