modalitas

Modalitas is a term used in philosophy and linguistics to refer to modality—the ways in which propositions can be true beyond their actual truth value. The word comes from Latin modalitas, built from modus “mode” with the suffix -itas, and in English yields the concept of modality or modal status.

In philosophy, modalitas encompasses different modes of truth, such as alethic modalities (possibility, necessity, impossibility) and non-alephic varieties (contingency, impossibility). Philosophers distinguish between how things might be (possibility) and how things must be (necessity), as well as normative or epistemic modalities related to obligation, permission, knowledge, and belief. A common framework uses possible-world semantics, where a proposition is necessarily true if it is true in all possible worlds, and possibly true if true in some accessible world.

In linguistics, modalitas deals with how languages encode modality through mood and modal expressions, commonly via modal verbs like can, may, must, and might. Modal systems vary across languages, reflecting differences in evidentiality, temporality, probability, and obligation. Some languages rely on auxiliary verbs, while others use mood inflections or dedicated particles. Modality interacts with syntax and semantics, including evidential and tense information, and plays a key role in discourse, argumentation, and pragmatics.

Modalitas also appears in logic and computer science, where modal logics formalize necessity and possibility with operators such as □ and ◇ and are used in areas like verification, knowledge representation, and AI planning.