The purpose of this paper is to formulate an affirmative explanation of the concept of use in Wittgenstein's Philosophical Investigation. As far as we know, there has abundant interpretation and explanation of this idea, but as I consider it, I find not each of them can serve as an affirmative answer to what is use. In the first two sections, I indicate three kinds of interpretation as non-affirmative explanation of use. The first one declines the most significant work of Philosophical Investigation is to criticize certain attractive but totally wrong picture of our language. The second one focuses on the uncountable relevant factor in concrete context of linguistic practice. The third one tries to explain the concept of use by some more complex or equivalent concept (ex. successful application) which lead our understanding nowhere. I agree the former interpretations could be correct according certain fragments of Philosophical Investigation, but they are helpless and hopeless in giving a constructive way of our thought and language.
But there is a good reason for the former negative answers. Wittgenstein is famous for his attacking on overt universallization of important philosophical concept. He warned us against the forced common feature of linguistic practice and use should not be any universal of our linguistic practice. But how can we understand a concept without any description of it? He suggested that we should look for proper example of games instead of the proper definition. The affirmative explanation of use should be a proper example instead of description.
The adequate examples in explaining Wittgenstein's concept of use are sentences which can have observable influence. The expressions or sentences express emotion or giving order are always his favorite instances in discussion. It is the influence of our words rather than any cognitive information makes our sound language. Use theory of meaning could be seen as a conceptual scheme which tries to understand the nature of human thought by their effect on human action and behavior. This is what I called the affirmative answer. The last section also contain outline of my own project in interpreting Wittgenstein in this way.