What is the significance of the supernatural in "Julius Caesar"?
Depending on your definition of "supernatural," there are several significant incidents in the play that can fall into this category. Here are some examples:
1. The soothsayer. The soothsayer, or fortune-teller, warns Caesar to beware the ides of March. We see later that Caesar should not have dismissed this warning as he did; the ides of March became the day of his murder. A soothsayer may not be "supernatural," but the idea of predicting the future and fortune-telling is other-worldly at least.
2. Casca's encounters. During the scene where Casca talks about the terrible storm, we see a lot of other supernatural omens as well. For example, Casca describes seeing a lion walking through the streets of town, a man with his hands on fire, and an owl in the daytime. He takes these sightings as bad omens of danger to come.
3. Calpurnia's nightmares. Calpurnia has three nightmares about Caesar's murders, and begs him not to leave the house on the Ides of March. He ignores her, even though he is worried, because he doesn't want to seem like he is a servant to his wife's fears.
4. Caesar's Ghost. A spirit, identified as Caesar's ghost, appears to Brutus while he prepares to battle with Antony's army. It tells him they will meet again at Phillippi, and leaves. Brutus is scared by this apparition.
Throughout the play, supernatural elements appear to forewarn the characters of impending doom.