Brutus' soliloquy regarding the proposed assassination of Caesar occurs in the opening scene of Act II.
It must be by his death, and, for my part,
I know no personal cause to spurn at him,
But for the general. He would be crown'd:
How that might change his nature, there's the question.
It is the bright day that brings forth the adder
And that craves wary walking. Crown him? that;
And then, I grant, we put a sting in him
That at his will he may do danger with.
The abuse of greatness is when it disjoins
Remorse from power, and, to speak truth of Caesar,
I have not known when his affections sway'd
More than his reason. But 'tis a common proof
That lowliness is young ambition's ladder,
Whereto the climber-upward turns his face;
But when he once attains the upmost round,
He then unto the ladder turns his back,
Looks in the clouds, scorning the base degrees
By which he did ascend. So Caesar may;
Then, lest he may, prevent. And, since the quarrel
Will bear no color for the thing he is,
Fashion it thus, that what he is, augmented,
Would run to these and these extremities;
And therefore think him as a serpent's egg
Which hatch'd would as his kind grow mischievous,
And kill him in the shell.
The soliloquy, like some of Robert Browning's dramatic monologues, is effective in characterizing the speaker. Brutus.is a serious, thoughtful, honorable person. He is not a violent man, but a thinker. He is a much better man than Cassius or Casca, or any of the other men who are ultimately recruited to join in the assassination. He cannot just go ahead and participate in the murder of Julius Caesar because he envies him or is afraid of him or thinks he might suffer financially. Brutus has to justify the deed to his reason and to his conscience. He is very much like Hamlet, whose soliloquies show that he is trying to rationalize murdering his uncle King Claudius. Brutus might also be compared to Macbeth in the early part of Shakespeare's play. Macbeth speaks a long soliloquy in Act 1, Scene 7 in which he gives himself all the reasons why he should not go ahead with the plan to murder Duncan, ending with the lines
I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other—
He is interrupted by Lady Macbeth. Otherwise he would have said the word "side." The image is one of a man vaulting onto the back of a horse but leaping too impetuously and falling on the ground on the other side of the horse.
What these soliloquies in Julius Caesar, Hamlet, and Macbeth have in common is that they show internal conflict. And conflict is the essence of drama. (Othello also experiences a lot of internal conflict in that play.) We want to know what these men are going to do. They are all agonizing over that question themselves. Macbeth only goes ahead with killing Duncan because his wife will give him no peace until he agrees to do it. Hamlet never really makes up his mind to kill Claudius. He is forced into it when he learns that Claudius wanted to have him beheaded in England and then is told by Laertes that Claudius initiated the plan to have him killed in their fencing match.
Brutus comes to a decision to lead the assassination attempt against Caesar based mainly on his patriotism. He admits to himself that he has nothing personal against Caesar but will act against him if it is for the good of Rome. Shakespeare wished to show that Brutus was noble because he was unselfish and patriotic. Shortly after speaking his soliloquy, Brutus receives some anonymous letters urging him to act. They were all prepared by Cassius, but Brutus believes they come from numerous citizens all calling on him to act for the good of Rome, just as his ancestors did in earlier times. Brutus is moved by these letters and says:
Am I entreated
To speak and strike? O Rome, I make thee promise,
If the redress will follow, thou receivest
Thy full petition at the hand of Brutus!
So the dramatic interest evoked by Brutus' internal conflict is resolved. Now follows the external conflict of organizing and carrying out the assassination attempt. It will be dangerous to strike at Caesar when he is making a public appearance, but it will be dangerous enough even to try to recruit other men who might warn Caesar. It will be dangerous even to talk about it or think about it. If Caesar became suspicious he might strike himself--and he is fully capable of doing so.