‘Polarity distinctions’ (Positive: “it is the case that SoA [state of affairs], and Negative: “it is not the case that SoA”) may be regarded as the logical extremes of Epistemic objective modality: they signal that the speaker is certain about the actuality or non-actuality of the SoA.
- Dik (1989), a pag.205

Objective modality can be divided into two sub-areas: (i) “Epistemic objective modality”, in which the speaker evaluates the actuality of the SoA [state of affairs] in terms of his knowledge of SoAs in general; (ii) “Deontic objective modality”, in which the actuality of the SoA is evaluated in terms of a system of moral, legal, or social norms. These sub-areas yield the following two scales of potential distinctions: (70) ‘Epistemic objective modalities’ Certain-Probable-Possible-Improbable-Impossible (71) ‘Deontic objective modalities’ Obligatory-Acceptable-Permissible-Unacceptable- Forbidden […].
- Dik (1989), a pag.205