Exigence

According to Lloyd Bitzer 's model, exigence is an "imperfection marked by urgency, a defect, an obstacle, something waiting to be done, a thing which is other than it should be" [1] (6). In common usage, exigence is often synonymous with problem.

According to Bitzer, there are two main types of exigence. An exigence is rhetorical if it can be mediated through discourse and through discourse alone. In plain language, this means that a rhetor cannot solve the problem alone but can persuade an audience to collaboratively act on it to solve or lessen it  [1].

An exigence is not rhetorical if the rhetor  can solve it alone through solo physical or mental exertion. An exigence is also not rhetorical if it cannot be solved through discourse, that is the rhetor persuading an audience to act collaboratively on it. Two examples Bitzer  gives as non-rhetorical exigencies are death and the weather  [1].

Reference
Notes:

[1] ^Bitzer, Lloyd. "The Rhetorical Situation ." Philosophy and Rhetoric 1 (1968): 1-14.