Zeus is presented as the ultimate tyrant because he will not honor the rules of friendship or understand such things as friendship, love, or sympathy. Zeus punishes Prometheus even though Prometheus was the deciding factor in his victory over the Titans. The punishment is presented as particularly reprehensible not because it is so harsh, but because it is imposed on someone who was a friend. Aeschylus intentionally highlights this fact by inserting references to friendship throughout the play. Hephaestus mentions that Zeus's orders trouble him because of his bond of friendship with Prometheus, and Oceanus offers his help out of friendship. The Chorus, despite counseling obedience throughout the play, suddenly switches at the end to affirming friendship as a greater value. Moreover, at least one major reason for Prometheus's punishment is that he values his friendship with human beings above reverence for Zeus. The reason Zeus cannot understand friendship lies in his self-confidence and the accompanying belief that all must obey him. Prometheus's insistence on the importance of friendship, bolstered by the Chorus at the conclusion of the play, suggests that obedience is only a secondary value. Zeus's tyranny appears as evil and misguided rather than deserved and just. In moral terms, it seems, it is not better to be feared than loved.
Prometheus and Zeus square off as the representative of intelligence and the invisible symbol of force, respectively. Prometheus helped Zeus defeat the Titans by using guile. When Prometheus attempted to use his intelligence to aid humanity, however, Zeus used his force to punish Prometheus. The conflict is emphasized throughout the play—Zeus's henchmen mock Prometheus for not being clever enough to avoid or escape punishment, and both the Chorus and Oceanus chide him for this in a more sympathetic manner. Yet Prometheus makes clear that without his knowledge Zeus will fall, overthrown by a power greater than his own. Force can overwhelm thought but cannot exist indefinitely without it. In Prometheus Bound Aeschylus intentionally cultivates an apparently irresolvable conflict between force and intelligence by presenting Prometheus as the powerless but defiant victim of an unjust and powerful god who rules by arbitrary laws and demands blind obedience. Underlying this conflict, however, is the idea that force requires thought to guide and sustain it. Aeschylus is clearly preparing us for a resolution where thought and force work together to avoid catastrophe. Prometheus's thoughtful defiance, in opposition to the unthinking obedience of Zeus's cronies, underscores the idea that thought must be sustained. Prometheus's clear judgment will one day save Zeus, while his opposition to Zeus is a necessary stage on the path to resolution.
Both Prometheus and Zeus are constantly accused of being too excessive in their stubbornness. Prometheus will not obey and Zeus will not end his punishment. Even in love Zeus is shown to be excessive, as his obsession with Io ruins her life. As we have seen, excess is the greatest sin in Greek moral thought. The healthy functioning of the universe requires the cooperation of opposing elements, such as thought and power, and the avoidance of excessive positions. Nothing good can come of conflict. The Chorus constantly emphasizes this moral belief while counseling Prometheus to tone down his defiance. In Greek tragedy excess, usually excess of pride, is almost universally condemned. Here, although they lead to Prometheus's suffering, his excessive pride and defiance are clearly praised, though perhaps with some reservations. This makes sense only if we assume that a resolution was originally part of the complete trilogy of plays. Yet in the only extant part of the trilogy the lack of a resolution and, in fact, the building up toward a climax where a resolution appears impossible, the excessive defiance of Prometheus makes for a masterpiece. Prometheus becomes the first great rebel of Western civilization. His excess is painted as a heroic feature of an individual faced with unbeatable odds and yet clinging resolutely to his certainty that he will prevail.
Prometheus stands for human progress against the forces of nature. We learn close to the beginning that he has given humanity the gifts of fire and hope. Hope helps human beings to struggle for a better future while fire, as the source of technology, makes success in that struggle possible. Prometheus lists his gifts to humanity in a progressive order, starting with the things necessary for survival and continuing on to the tools of commerce and economic expansion. Aeschylus here expresses a faith in human progress, and there is at least a veiled implication that Zeus feels threatened by this progress. The gods are at least partially personifications of nature. Human progress is the slow advance of humanity against the threatening elements of nature. In a sense, progress threatens to do away with the gods as nature is slowly understood and conquered through technology. Prometheus's contribution of technological gifts to humanity thus endangers the other gods and he is punished for bestowing on human beings the favors that rightly belong to the gods alone. Yet the faith in human progress as Aeschylus expresses it is clearly a new mode of thought in Greek civilization, and it is one that would be echoed more than a millennium later in the thought of the Enlightenment. It is clear that Aeschylus opposes the earlier view of Hesiod that human civilization has slowly been slipping for a perfect Golden Age into a decrepit Bronze Age. In Prometheus's words, humanity advances from dire need and fear of nature to a deeper understanding, advancement in survival, art, divination, and finally mining, which symbolizes the progress of civilization in the consecutive discovery and use of bronze, iron, silver, and finally gold.
The yoke and harness is a motif recurring throughout the play from beginning to end, and used in all cases except one to stand in for Zeus's tyrannical power. Hephaestus and Prometheus speak of the bonds as a harness. Io compares her torture to a yoke and applies the same terminology in explaining how her father was forced to exile her. Hermes compares Prometheus to a young colt biting at the bit. The persistent repetition of this motif serves to leave us with a particular impression of Zeus's power. We are never told of anything positive that is done with this power, while domination of others seems to be Zeus's only concern. This imagery also strengthens the identification of Zeus with force as opposed to Prometheus's thought. Zeus's exclusive focus on the yoking and harnessing of others is also central to the persistent references to him as a tyrant. Interestingly, the motif appears once without reference to Zeus, when Prometheus lists his gifts to humanity. Not only does he mention that he taught humans how to harness animals, but he dwells on this gift more than on the others, insisting that it was he who first put a yoke on an animal. A few interesting interpretations of this emphasis are possible. Prometheus may be suggesting that the yoke can be used for beneficial and life preserving purposes rather than the purposes to which Zeus puts it. Alternatively, there is a suggestion that Prometheus has given human beings the power to harness others, which previously was a gift reserved exclusively for Zeus.
Time is referred to throughout the play, bolstered by related motifs of Zeus's newness as ruler, generational conflicts among the gods, and the importance of Fate. Prometheus shows a certain conflict between speaking and remaining silent, knowing that the proper time to reveal his prophesy to Zeus has not yet come. In connection with the importance of delay here, conversations in the play often involve procrastination techniques. It takes repeated prodding by the Chorus to get Prometheus to tell the true cause of his punishment, and a similar scenario is repeated with Io. Prometheus suggests that there is a right time and a wrong time for reconciliation, but that at the right time both sides will be ready. Repeated references are made to Zeus's newness as a ruler, weakening his claim to power somewhat, since age is seen as a mark of power. Human beings, for example, are seen as insignificant because they are only "creatures of a day." The passing of time is significant for the generational conflict referred to throughout the play: the older Titans battled the younger Zeus and lost so that a new generation now sits in power. The conflict yields credibility to the prophecy that Zeus will be overthrown by a future son, thus continuing the generational strife. Finally, time is important in its link to Fate. Fate decrees how an individual's life progresses through time and it mandates a particular unchangeable future. Fate, as Prometheus points out, is stronger than Zeus himself, so that even the greatest power is trapped along with all others in the stream of time.