The text most often referred to in discussions of divine command theory is Plato’s Euthyphro. The Euthyphro is a dialogue between Socrates and Euthyphro, set outside the court-house in Athens. Socrates is attending the court having been indicted for corrupting the young with impiety. Euthyphro is attending the court in order to indict his father for the murder of a household slave.

When Socrates hears of the reason for Euthyphro’s presence outside the court he takes heart. Surely one willing to bring charges against his own father must have certain knowledge of piety and impiety, Socrates reasons. No one, he thinks, would set out on such a course unless they were absolutely sure that it was the right thing to do. Socrates forms a plan: he requests that Euthyphro teach him as to the nature of piety, in order that he might inform the court that he has learned the error of his ways and presents no further risk to the young.

Euthyphro, however, is unable to help Socrates. In the course of their discussion he attempts several different analyses of piety, but none of these analyses stands up under scrutiny. The dialogue ends with Euthyphro making his excuses and leaving, and with Socrates still pleading with him to explain what piety is. Socrates never does learn the nature of piety, and is subsequently sentenced to death for his crimes. The irony, of course, is that the Euthyphro dialogue shows that even the well-respected citizens of Athens do not understand piety and impiety, and so that Socrates‘ sentence was imposed by a jury that did not understand his crime.

Among Euthyphro’s attempted analyses of piety is one that has been taken to be an unsophisticated form of divine command theory. At one point in the discussion, Euthyphro affirms that “the pious is what all the gods love, and the opposite, what all the gods hate, is the impious”. As with each of Euthyphro’s other attempted definitions, he is unable to defend this theory under questioning from Socrates. The line of questioning by which Socrates undermines Euthyphro’s theory has been the inspiration for many modern critics of divine command theory proper.

The crux of Socrates‘ line of questioning is usually taken to be his query, “Is the pious loved by the gods because it is pious, or is it pious because it is loved by the gods?” This question has given rise to an argument that is now known as the Euthyphro dilemma, and which is thought by many to refute divine command theory. The Euthyphro dilemma rests on a modernised version of the question asked by Socrates: “Are morally good acts willed by God because they are morally good, or are they morally good because they are willed by God?” Each of these two possibilities, the argument runs, leads to consequences that the divine command theorist cannot accept. Whichever way the divine command theorist answers this question, then, it seems that his theory will be refuted.