Functions of Language
The formal patterns of correct reasoning can all be conveyed through ordinary language, but then so can a lot of other things. In fact, we use language in many different ways, some of which are irrelevant to any attempt to provide reasons for what we believe. It is helpful to identify at least three distinct uses of language:
1. The informative use of language involves an effort to communicate some content. When I tell a child, „The fifth of May is a Mexican holiday,“ or write to you that „Logic is the study of correct reasoning,“ or jot a note to myself, „Jennifer—555-3769,“ I am using language informatively. This kind of use presumes that the content of what is being communicated is actually true, so it will be our central focus in the study of logic.
2. An expressive use of language, on the other hand, intends only to vent some feeling, or perhaps to evoke some feeling from other people. When I say, „Friday afternoons are dreary,“ or yell „Ouch!“ I am using language expressively. Although such uses don’t convey any information, they do serve an important function in everyday life, since how we feel sometimes matters as much as—or more than—what we hold to be true.
3. Finally, directive uses of language aim to cause or to prevent some overt action by a human agent. When I say „Shut the door,“ or write „Read the textbook,“ or memo myself, „Don’t rely so heavily on the passive voice,“ I am using language directively. The point in each of these cases is to make someone perform (or forswear) a particular action. This is a significant linguistic function, too, but like the expressive use, it doesn’t always relate logically to the truth of our beliefs.