Abstract: The possibility of practical logic is a core issue in contemporary philosophy and other rational enterprises. According to classical pragmatists, reasoning, in the first, was as a constitute of human life, not as a calculus external to the world. In general, all the logical reasoning were doing things reasonably, therefore, reasoning should be seen as a committed action or an intentional inquiry. This theory of reasoning offers a better alternative to the approach of informal logic or natural logic to practical reason. This paper gives a outline of a theory of reasoning in light of classical pragmatism, and responds to its main challenge and made some prospects for its philosophical relevance.

Key words: theory of reaoning, pragmatism, Peirce, James, Dewey