Pragmatism is the distinctively American tradition holding that ideas, concepts and institutions are tools for coping with concrete problems and not representations of a reality standing behind experience. Its test of a belief is what difference the belief makes in practice. A distinction that changes nothing anywhere is not worth defending.
Charles Sanders Peirce set out the method in "How to Make Our Ideas Clear" (1878), fixing the meaning of a concept in its conceivable practical effects. William James popularized it and pushed it toward a theory of truth as what proves workable in the long run, a move Peirce disliked enough to rename his own position. John Dewey then made pragmatism a political philosophy, treating democracy as a mode of associated living in which institutions stay open to revision by the people affected by them, and modeling inquiry on experiment instead of on proof.
Dewey's exchange with Walter Lippmann in the 1920s remains the sharpest argument inside the tradition. Lippmann held that modern publics are too distracted and ill-informed to govern complex societies and that administration should fall to experts. Dewey conceded most of the diagnosis and rejected the conclusion, arguing that the public's incapacity was a product of its exclusion and not a reason for it. Richard Rorty later revived pragmatism in a more skeptical register, dropping the residual scientism and arguing that philosophy should abandon the search for foundations altogether.
The standing objection is that a philosophy measuring ideas by what works supplies no ground for saying that something which works is wrong, so pragmatism is well equipped to reform institutions and poorly equipped to condemn them. Pragmatists answer that no rival account of truth has done better at explaining how fallible inquirers actually correct themselves, and that foundations have historically been claimed more often than they have been supplied.