Why does Shakespeare make Caesar change his mind so often in this scene?

The fact that Caesar changes his mind often during this scene is directly related to superstition and the Romans' belief in omens foretelling the future. Caesar's wife has had a nightmare, the sacrifice gives him warning, and yet, Caesar is afraid of appearing cowardly. Thus, he goes to the Senate regardless, and reinterprets the omens to alleviate his wife's fears.