The modality of a proposition p is the attitude towards its realization. Modalities are divided by two criteria:

1. Who/where is the source of the attitude:
   • The source may be an impersonal instance, i.o.w. no source is identified. Modalized p is presented as if the modality was just an objective fact of the world. This is objective modality.
   • The source may be the origo. This is subjective modality.
   • The source may be a participant of p, commonly coded as its subject. This is situational modality.
2. What does the source do about the reality of p?
   • The source may exert energy on the realization of p. This is deontic modality. It comprises debitive and volitive modality.
   • The source may assess and state how real p is. This is epistemic modality. It comprises potential, permissive and inferential modality.

Subjective modality and objective modality are seldom distinguished in linguistic structure. Commonly, subjective modality is coded as impersonal, as if there was a supernatural instance determining the realization of p.

Modality differs from illocution in that modality is a binary, cognitive relation between a source and p, while illocution is a ternary, communicative relation between the speaker/origo, the hearer and p.

Different modalities are compatible with both declarative and interrogative illocution. However, under interrogative illocution, the source of subjective modality shifts to the hearer. There are no distinct modalities under imperative illocution.

It is possible for an illocutionary force to be based on a modality.

For instance, codes objective permissive modality: ‘(As far as I know,) Linda has a permit to go out at night’. However, under appropriate circumstances, it may be interpreted as the speech act of permission: ‘I hereby tell you that I allow Linda to go out at night.’