 Four of the dialogues in this group are concerned with  definition  of virtues or good qualities:  Euthyphro  (piety or reverence),  Laches  (courage),  Charmides  (temperance, integrity, or soundness of mind), and  Hippias Major  (the fine or beautiful). These dialogues of definition indirectly raise questions about the mutual relations of the virtues, and this question is taken up explicitly in the  Protagoras,  which introduces the doctrines of the  unity of virtue  and the impossibility of  acrasia  (the doctrine that it is impossible to know what is right and still do wrong). A corollary of this is the claim that no one does wrong willingly, which supports part of Socrates’ argument in the Apology. Another corollary is that in seeking virtue we should seek knowledge about virtue. Nevertheless, Socrates entertains strong doubts as to the teachability of virtue. Socrates sometimes treats virtue on the analogy of  techne,  however, and techne means a body of specialized knowledge that can be taught. 