Plato presents the character Euthyphro as a person who lacks self-knowledge. In this dialogue Euthyphro has filed murder charges against his own father. In defence of his actions Euthyphro relates the following story to the philosopher Socrates: One of Euthyphro’s dependent labourers got drunk and killed a domestic servant of the family. On discovering this, Euthyphro’s father bound the labourer hand and foot and left him unfed and exposed to the elements. The father then sought the advice of religious authorities on how to deal with the murderer.
During this period, the man died of exposure or starvation. Despite the outrage of his family and friends, Euthyphro feels confident that his father’s neglect of the man constitutes murder. He claims that filing charges is the only pious (or holy) thing to do. Euthyphro presents himself as a deeply pious man who does not, like ordinary people, shirk his moral responsibilities simply because they run contrary to his own interests or feelings of loyalty to his family. Socrates then engages Euthyphro in a dialogue to determine whether he really understands his own actions.
Socrates does this by asking Euthyphro for the meaning of piety. Euthyphro initially responds by giving examples of what he regards as pious behaviour. Socrates rejects this answer, explaining that a definition of piety must show what all examples of piety have in common. Euthyphro eventually offers the following definition: Piety is that which is dear to the gods. Socrates then proceeds to show that this definition is inadequate. He provides two important arguments.
This is a logical contradiction and sufficient grounds for rejecting Euthyphro’s definition of piety. Socrates’ second argument consists in showing Euthyphro that in fact he does not really even accept his own definition. Socrates does this by posing the following question: Is something pious or holy because it is dear to the gods, or, rather, is it dear to the gods because it is holy? Socrates explains that if something is holy just in virtue of being dear to the gods, then it would lose its holiness if it ceased to be dear to the gods.
But this contradicts the assumption that holiness is an eternal attribute; i. e. , something that is holy now must be holy forever. This leaves the second option, viz. , that something is dear to the gods because it is holy. This, according to Socrates, is the right answer. However, he explains that if holiness is to constitute a reason for a thing being dear to the gods, then holiness and being to be dear to the gods can not actually be the same thing. This is because something can not be a reason for itself.
Euthyphro demonstrates his lack of self knowledge by revealing that he does not actually understand the reasons he has given for prosecuting his father. Although he claims that his actions are pious, in fact he has no idea what piety is. Despite Socrates arguments, at the end of the dialogue Euthyphro is certain that he really does know what piety is, but that he just finds it difficult to explain. Plato makes his case for the importance of self-knowledge by showing how much harm can be done when a lack of self knowledge is combined with a smug certainty of ones moral superiority over others.