In his ruminations about his lack of attachment, Orestes brings up the motif of weight. Speaking of all the archaeological knowledge he has acquired, he asks, "with all these stones in my head, why am I not heavier?" Orestes complains that he is too light. He has no commitments and no real memories. He has been brought up to be detached from all human communities and as a result he feels that he has nothing of his own. The ability of human beings to create and define themselves is a cornerstone of Sartre's philosophy. Orestes has never attached himself to any society, idea, or thought—the things that make one heavy. Instead, he is completely detached from everyone and everything, floating above the world. Orestes complains that he is as light as air; nothing weighs him down. He longs to attach himself to something so that he can acquire an identity and feel at one with the human world. Someone who is light, who has not created a self-identity, is not fully human. Orestes's complaint is not that he is alone, but rather that his identity lacks content.
Sartre's departure from the Greek myth is important to the message of his play. In Aeschylus's The Libation Bearers, it is Orestes's destiny to avenge his father's murder by killing those who were responsible for his death. He is also ordered to do so by Apollo. Neither case ensues in The Flies. In speaking with the Tutor, Orestes states that he did not have a purpose in coming to Argos. He has not been ordered to do so, and he has no set destiny. The lack of a destiny is emphasized in Jupiter's speech, which makes no mention of revenge. Jupiter merely seeks to dissuade Orestes from freeing the people of Argos from their repentance; he does not attempt to dissuade him from avenging his father's death because revenge is not important to Orestes. Revenge is always grounded in the past: it comes from a need to fix something that has already happened. Orestes, however, looks only to the future; he emphasizes that he lacks a past. Since the necessity of revenge is the origin of Orestes's destiny in the Greek myth, the lack of reference to revenge here underscores the lack of a destiny for Orestes. Sartre emphasizes that Orestes's action is completely free and comes from himself, not some outside force. To this end he shows us that there is nothing in the past driving Orestes towards his action. Orestes refuses to seriously entertain the idea of killing the king and queen. He is sincere when he states that killing them and taking the throne are only "idle dreams."
The implicit rejection of revenge as the motive for action is also significant because it brings another possible motive to the forefront: the liberation of others. Jupiter introduces the idea that the murder of Aegistheus and Clytemnestra might free the people of Argos. Part of Sartre's goal in the play is to stress the liberation of others as a motive for action, since he wants to encourage resistance against the Nazi occupation of France. If Orestes is to kill the usurpers of the throne, he must have a motivation for doing so. Since that motivation cannot be revenge, it must be liberation. What is important here is that this liberation is not physical. Aegistheus does not control the Argives through force. They are enslaved psychologically, by repentance and fear. If any liberation is to take place, it cannot be a physical liberation; it must be an ideological one.