Final answer:
Aristotle's first principle and soul of tragedy, as mentioned in his Poetics, is the Plot. This element is critical as it structurally designs events to evoke emotional responses such as pity and fear, ultimately leading to catharsis. While other elements like character and diction are also important, it is the plot that is paramount in a tragedy.
Step-by-step explanation:
According to Aristotle in his Poetics, the first principle and soul of tragedy is the Plot. He breaks tragedy down into six integral parts: Plot, Character, Diction, Thought, Spectacle, and Song. He emphasizes that tragedy is essentially an imitation of an action that is serious and significant, using language that is artistically ornate, in a manner that intends to evoke pity and fear, leading to the catharsis of these emotions.
Aristotle likens the importance of plot in tragedy to the outline in a painting, suggesting that the most beautiful colors applied without structure will not please as much as the mere outline of a portrait. This implies that the structural design of events in a tragedy, the plot, stands as the core that carries the weight of evoking emotional responses in the audience through carefully crafted incidents like Reversal of the Situation and Recognition scenes. He posits that, while character is important, it is subsidiary to the actions that define the course of the tragedy.
Tragedy, as per Aristotle, should concern itself with actions and events that have relevance beyond the personal, often involving characters of noble birth caught in ethical dilemmas or grave situations, such as the classic tale of Oedipus. It's the unfolding of these actions that dramatizes and elevates a play into the realm of tragedy, forging a poignant emphatic connection with the audience through the protagonists' choices and fates.