What is the opposite of modal?

Is there a word for the opposite of modal?

Particularly, is there a word for the opposite of modal in the logical sense of relating to the modality between propositions? In other words, is there a word for denoting that of not relating to the modality between propositions?

At the risk of trivializing the issue, why not at least try non-modal? That is not an opposite, exactly, but it covers the bases I think you need covered.

Modal means "having modes".

In the field of user interface design, a modal interface is one in which a given action has different results depending on what "mode" the system is in. For example, a button on a digital watch might advance the current time by a minute in one mode, and turn on the face light in another mode.

The opposite of modal in this field is modeless. Modelessness is considered desirable in a user interface, because the user doesn't need to think about what mode they are in.

It's not in dictionaries; it's not in my spellchecker. But it is widely used for this purpose. It might work for your purpose too.

This seems to me a question for the technical audience, say logicians or linguists, that they have decided to use. In both cases, 'modal' is highly marked, which means that by default, if the word 'modal' is not mentioned, then it is assumed to be not modal.

But in those instances where the contrast must be expressed:

• For logicians, modal is used in contrast to classical logic, quantifiers, or operators.
• For linguists, the contrast is to an infinitive or declarative verb.