In the paper, by involving N.Tusi’s treatise “Tajrid al-mantik”, Hilli’s commentaries to this treatise, and N.Tusi’s commentaries to the Ibn Sina’s logical treatise “’al-Isharat vat-tanbihat” bases moments corresponding to modal propositions, their classification, connection between them and influence of quantifiers in such propositions are studied.

Purpose: the investigation of classical heritage on logics by involving original works

Methodology: inner analyses and comparatively investigation of classical materials.

Scientific novelty: by involving classical works, the modal propositions, their classification and quantity characteristics are studied.