Those who have virtue always in their mouths, and neglect it in practice, are like a harp, which emits a sound pleasing to others, while itself is insensible of the music. – Diogenes of Sinope
Diogenes of Sinope was an ancient Greek philosopher, who was one of the most well known and most controversial of the Cynics. Diogenes is also known as Diogenes the dog (Διογένης ὁ Κυνικός, Diogenēs ho Kunikos) which is the supposed origin of the term Cynic (Doglike).
One of the core ideas of Cynicism and of Diogenes is that philosophy is practical, and as a result, philosophical questions are ones that deal with the ‘everydayness’ of life, with the goal of these thought provoking questions being action. This is evident in Diogenes through his idea of Solvitur Ambulando, or, it is solved by walking (practical experiment). The quote above illustrates this core cynic idea, as the person who speaks of virtue applies none of them to their own life. Their failure to grasp the purpose of philosophy means they hear nothing where others hear music, they speak of virtues while others live by them, they miss the point, while others take action, they are reduced to mere objects, incapable of living a virtuous life for they do not grasp the connection between philosophy and life.