What is the theme / philosophy behind this play and his plays in general?

Themes

Reason vs. Power

One of the great themes of Prometheus Bound is the frustration and helplessness of reason and rightness in the face of sheer power. Aeschylus hammers the theme home by having Prometheus chained by two demonic forces with allegorical names. Violence, appropriately, is mute, and in many productions Violence is played as a kind of beast. Might is a ruthless, pitiless deity, without any will of his own. He is the fist of Zeus: cold, cruel, the institution of tyranny personified. Viewing Prometheus as reason, we see the play as partly the story of reason's tragic limits, and its helplessness in the face of brutal, unthinking force.

Individual of Conscience vs. Tyranny

This theme is closely connected to the theme of Reason vs. Power. As in the Oresteia, Aeschylus gives us a magnificent net of symbols and metaphor, all working on multiple levels at once. Prometheus is reason and wisdom personified; he is also the individual of conscience in a totalitarian state. Anxiety about tyranny surfaces often in Greek plays. For Athenians, who considered themselves freer than their neighbors, fear of losing that freedom was an obsession. Zeus, like the tyrants of the real world, crosses the lines of custom and unwritten law. His punishment of Prometheus is excessive and in poor taste.

Prometheus is the rebel with a conscience whose crime, his love of man, brings on him both the rage of the gods and the immediate sympathy of the human audience. Prometheus becomes a representative for those human champions of justice and principle who defy tyranny and pay the ultimate price.

Fate

Fate is another oft-explored theme in Greek tragedies. Part of the power of tragedy is the sense of inevitability. This play is unique in that the whole work is one extended Scene of Suffering. Prometheus is literally chained by his fate. Prometheus' name means "Forethinker"; through his connection with his mother Themis, the earth, he can see the future. This power is both gift and curse. Prometheus suffers, and knows he cannot escape his long years of torture. But he also knows that one day he will be set free, and he possesses a piece of strategic knowledge that could preserve or destroy Zeus's reign. (See "Prometheus the Prophet and Visionary," below).

Prometheus' Roles

Many of the themes of the play center on the awesome figure of Prometheus himself, he becomes a representative of many powerful ideas and forces. Listed below are a few general categories.

Prometheus the Prophet and Visionary

This is perhaps the most powerful and all-encompassing of the titan's roles. Prometheus is a powerful metaphor for countless visionaries, scientists, statesmen, and artists whose work was not appreciated or understood in their own time. Many of these men and women tried to comfort themselves, as Prometheus does, by assuring themselves that one day recognition will come. But when the world is not ready for a certain kind of knowledge, being the bearer of that knowledge is painful and lonely. The Prometheus story reflects this pain and isolation in the punishment inflicted on its protagonist: part of his suffering will be the long, terrible years of loneliness he will spend, wasting away, not knowing if the sound of approaching footsteps signals a friend bringing comfort or an enemy planning to torture or ridicule him. Some versions of the myth credit him with creating man. This story reinforces Prometheus as a symbol for the supreme artist, suffering for his creation.

Prometheus the Craftsman, and Prometheus the Creator

Prometheus is the supreme artist, the master storyteller who holds the attention of the audience and the chorus, the master craftsman and creator who makes and then instructs man. Both Prometheus and fire are symbols of the creative and ingenious spark in man: "In one short sentence understand it all: / every art of mankind comes from Prometheus" (ll. 506-7). Significantly, Prometheus molds man to follow his example in some ways. He gives them fire, so that they will create. He instructs them to be craftsmen, as he is. Prometheus the Creator is also the visionary artist. His most beautiful creation, man, is also the most despised by Zeus.

Prometheus the Champion of Mankind, and Prometheus the Sufferer

Despite the fact that mortal men can do nothing to help him, Prometheus remains the staunch ally of human beings. He defies the gods on their behalf. Prometheus as the great sufferer is an important theme of the play. In a way, the titan prefigures Christ: he is a divine being who suffers horrible tortures for the sake of mankind. The other gods seem a bit mystified by his willingness to suffer for man; after all, humans can do nothing for him, and they are inferior beings. Prometheus' willing sacrifice is the ultimate gesture he can make for mankind, as well as an example for mankind to follow. Symbolically, he is every great man whose greatness made him into a target.

Check out the educational resource below for a detailed look at influences on Aeschylus' philosophy.

http://www.academia.edu/5124917/Power_and_Nature_Aeschylus_s_Prometheus_Bound_and_Aristotle_s_Philosophy