The poem’s initial word, μῆνιν (mēnin, accusative of μῆνις, mēnis — wrath, rage, fury), establishes the Iliad's principal theme: The "Wrath of Achilles." His personal rage and wounded soldier’s vanity propel the story — the Greeks’ faltering in battle, the slayings of Patroclus and Hector, and the fall of Troy. In Book I, the Wrath of Achilles first emerges in the Achilles-convoked meeting, between the Greek kings and Calchas, the Seer. King Agamemnon dishonours Chryses, the Trojan Apollonian priest, by refusing with a threat the restitution of his daughter, Chryseis — despite the proffered ransom of “gifts beyond count”. The insulted priest prays his god’s help — and a nine-day rain of divine plague arrows falls upon the Greeks. Moreover, in that meeting, Achilles accuses Agamemnon of being “greediest for gain of all men”.
After that, only Athena stays Achilles’s wrath. He vows to never again obey orders from Agamemnon. Furious, Achilles cries to his mother, Thetis, who persuades Zeus’s divine intervention — favoring the Trojans — until Achilles’s rights are restored. Meanwhile, Hector leads the Trojans to almost pushing the Greeks back to the sea (Book XII). Later, Agamemnon contemplates defeat and retreat to Greece (Book XIV). Again, the Wrath of Achilles turns the war’s tide in seeking vengeance when Hector kills Patroclus. Aggrieved, Achilles tears his hair and dirties his face.
Accepting prospective death as fair price for avenging Patroclus, he returns to battle, dooming Hector and Troy, thrice chasing him ’round the Trojan walls, before slaying him, then dragging the corpse behind his chariot, back to camp.
Tragedy (Ancient Greek: τραγῳδία, tragōidia, "he-goat-song") is a form of art based on human suffering that offers its audience pleasure. While most cultures have developed forms that provoke this paradoxical response, tragedy refers to a specific tradition of drama that has played a unique and important role historically in the self-definition of Western civilisation. That tradition has been multiple and discontinuous, yet the term has often been used to invoke a powerful effect of cultural identity and historical continuity—"the Greeks and the Elizabethans, in one cultural form; Hellenes and Christians, in a common activity," as Raymond Williams puts it. From its obscure origins in the theatres of Athens 2,500 years ago, from which there survives only a fraction of the work of Aeschylus, Sophocles and Euripides, through its singular articulations in the works of Shakespeare, Lope de Vega, Racine, and Schiller, to the more recent naturalistic tragedy of Strindberg, Beckett's modernist meditations on death, loss and suffering, and Müller's postmodernist reworkings of the tragic canon, tragedy has remained an important site of cultural experimentation, negotiation, struggle, and change. A long line of philosophers—which includes Plato, Aristotle, Saint Augustine, Voltaire, Hume, Diderot, Hegel, Schopenhauer, Kierkegaard, Nietzsche, Freud, Benjamin, Camus, Lacan, and Deleuze—have analysed, speculated upon, and criticised the tragic form. In the wake of Aristotle's Poetics (335 BCE), tragedy has been used to make genre distinctions, whether at the scale of poetry in general (where the tragic divides against epic and lyric) or at the scale of the drama (where tragedy is opposed to comedy). In the modern era, tragedy has also been defined against drama, melodrama, the tragicomic, and epic theatre.
In 1977, physicists E. C. G. Sudarshan and B. Misra studying quantum mechanics discovered that the dynamical evolution (motion) of a quantum system can be hindered (or even inhibited) through observation of the system. This effect is usually called the "quantum Zeno effect" as it is strongly reminiscent of Zeno's arrow paradox.
This effect was first theorized in 1958.