Socratic method, or the method of refutation (elenchus). It is most prominent in the early works of Plato, such as Apology, Crito, Gorgias, Republic I, and others. The typical elenchus proceeds as follows. Socrates initiates a discussion about a topic with a known expert on the subject, usually in the company of some young men and boys, and by dialogue proves the expert's beliefs and arguments to be contradictory. Socrates initiates the dialogue by asking his interlocutor for a definition of the subject. As he asks more questions, the interlocutor's answers eventually contradict the first definition. The conclusion is that the expert did not really know the definition in the first place. The interlocutor may come up with a different definition. That new definition, in turn, comes under the scrutiny of Socratic questioning. With each round of question and answer, Socrates and his interlocutor hope to approach the truth. More often, they continue to reveal their ignorance. Since the interlocutors' definitions most commonly represent the mainstream opinion on a matter, the discussion places doubt on the common opinion. Socrates also tests his own opinions through the Socratic method. Thus Socrates does not teach a fixed philosophical doctrine. Rather, he acknowledges his own ignorance while searching for truth with his pupils and interlocutors. Scholars have questioned the validity and the exact nature of the Socratic method, or indeed if there even was a Socratic method. In 1982, the scholar of ancient philosophy Gregory Vlastos claimed that the Socratic method could not be used to establish the truth or falsehood of a proposition. Rather, Vlastos argued, it was a way to show that an interlocutor's beliefs were inconsistent. There have been two main lines of thought regarding this view, depending on whether it is accepted that Socrates is seeking to prove a claim wrong. According to the first line of thought, known as the constructivist approach, Socrates indeed seeks to refute a claim by this method, and the method helps in reaching affirmative statements. The non-constructivist approach holds that Socrates merely wants to establish the inconsistency between the premises and conclusion of the initial argument. Socratic priority of definition Socrates starts his discussions by prioritizing the search for definitions. In most cases, Socrates initiates his discourse with an expert on a subject by seeking a definition—by asking, for example, what virtue, goodness, justice, or courage is. To establish a definition, Socrates first