The practice of refutation has been a central preoccupation of philosophers since Socrates. But what is a refutation? And why do philosophers feel impelled to produce them? With reference to the first question, I produce a definition of refutation: a refutation disproves one proposition in order to discredit another. With reference to the second question, I argue that the refuter’s activity to undermine her interlocutor's account solves a problem facing the project of knowledge-acquisition. This problem was articulated by William James: the project of coming to believe truths is in tension with the project of avoiding belief in falsehoods. The first motivates one to embrace dogmatism, the second to retreat to skepticism. The practice of refutation solves James’ problem by way of a division of labor.