One scholar has explained the relationship between The Flies and Sartre's philosophy thus:
- "The play explores the key existentialist themes of freedom and responsibility through the radical conversion of Philebus the peace loving intellectual into Orestes the warrior. A person may not be prepared for present crises by his past experiences, but it is nonetheless bad faith for him to declare, 'I was not meant for this' or 'This should not be happening to me.' Orestes resists bad faith and achieves authenticity by rising to the demands of his circumstances and fully realizing his being-in-situation."[8]
Sartre's idea of freedom specifically requires that the being-for-itself be neither a being-for-others nor a being-in-itself. A being-for-others occurs when human beings accept morals thrust onto them by others. A being-in-itself occurs when human beings do not separate themselves from objects of nature. Zeus represents both a moral norm, the Good, and Nature. Freedom is not the ability to physically do whatever one wants. It is the ability to mentally interpret one's own life for oneself—to define oneself and create one's own values. Even the slave can interpret his or her life in different ways, and in this sense the slave is free.
The Flies also shows the effect of Nietzsche on Sartre. Orestes represents the idea of the overman, as described in works such as Thus Spoke Zarathustra; the ability to free one's mind from dogma and the impressions of others, and instead think on a higher level. Like Zarathustra, Orestes feels he must "go down" to the people and open their eyes (though unlike Zarathustra, Orestes does it out of compassion). When debating Zeus, Orestes also talks about being "beyond" the moral yoke others allow to be placed on them - an idea explicitly discussed in Beyond Good and Evil, and implicitly described in other works by Nietzsche. Orestes is not bound by the false dichotomy of "good" and "evil," and instead accepts what has been done, choosing to focus on the present and the future.
Sartre continued a twentieth-century tradition of an incestuous flirtation between Électre and Oreste in Les Mouches. This flirtation may have been inspired by the incestuous siblings of Andre Gide’s Œdipe, and philosophically motivated by Gide and Sartre’s shared antipathy to Freud’s repression theory.[9]
