In Act 1, Scene 2, Brutus remarks to Cassius that Casca, with whom they have just conferred, seems to have lost his quick wit. Cassius uses a metaphor to explain that, in fact, Casca's style of speech is a deliberate choice:
What a blunt fellow is this grown to be!
He was quick mettle when he want to school.
So is he now in execution
Of any bold or noble enterprise,
However he puts on this tardy form.
This rudeness is a sauce to his good wit,
Which gives men stomach to digest his words
With better appetite.
Cassius justifies Casca’s apparent “bluntness,” or dullness, by comparing it to a sort of digestive aid, a delightful “sauce” that makes him more agreeable. Many of the characters in Julius Caesar rely on complex arguments and entangled literary devices to make their point, and Casca is a notable departure from this trend: for Casca, simple language makes it easier for him to be understood and, ultimately, for others to find him agreeable.
Shakespeare uses Julius Caesar as an opportunity to play with various modes of speech and rhetoric, displaying not only his versatility as a playwright but also the power of language in political argument. This sequence is evidence enough that one need not be a brilliant orator to be a convincing speaker. Even in a play famous for its elaborate speeches and passionate debates, less is sometimes more.
In Act 1, Scene 3, Cassius offers his withering opinion of Caesar. Using a set of nested metaphors, he sets up his rival as a lowly man who nonetheless presents a threat to the people of Rome if they do not pay attention:
And why should Caesar be a tyrant, then?
Poor man, I know he would not be a wolf
But that he sees the Romans are but sheep;
He were no lion, were not Romans hinds.
Those that with haste will make a mighty fire
Begin it with weak straws. What trash is Rome,
What rubbish, and what offal when it serves
For the base matter to illuminate
So vile a thing as Caesar!
Cassius demeans Caesar’s political prowess by accusing him of taking advantage of the weak Roman public using comparisons between the Romans being prey animals (sheep and hinds, or deer) who enable Caesar to act as a wolf or lion. Caesar “hastily” attempts to gain power, like the building of a fire, by manipulating the Roman populace like “weak straws,” fuel for his fire. Romans must be "rubbish," in Cassius’s view, to empower someone like Caesar.
This mixed metaphor conveys Cassius’s passionate angst as as he runs through a set of comparisons to convey his disdain for Caesar. Shakespeare also takes this opportunity to emphasizes a certain weakness in Cassius as an orator—his comparisons overlap in a bit of a jumble, though they do show the extent of Cassius's loathing.
Shakespeare pays particular attention to various uses of language and argument in Julius Caesar, as he examines the power of speech to affect political sentiment. This sequence presents Cassius at his most passionate and least refined. It also underscores a major point of pride for the political power players in Shakespeare's fictionalized Rome: manhood and honor are at the core of everything, and Cassius is keen to portray Caesar as a dishonorable and weak "wolf in sheep's clothing."
In Act 2, Scene 1, Brutus suffers under the burden of plotting against his old ally, Caesar. In a lengthy metaphor, he compares his body's visceral reaction to the stress of the situation to a kingdom in rebellion:
Since Cassius first did whet me against Caesar,
I have not slept.
Between the act of a dreadful thing
And the first motion, all the interim is
Like a phantasma or a hideous dream.
The genius and the mortal instruments
Are then in council, and the state of man,
Like to a little kingdom, suffers then
The nature of an insurrection.
In the nerve-racking time between crafting his plan against Caesar and executing it, Brutus's body feels like a "little kingdom" in the disarray of rebellion: his brain, "the genius," and his body, the "mortal instruments," plot against him, and he cannot sleep. This is a clever and extensive pun on the "body politic," the metaphorical description of a political body—like a city, state, or country—as a physical human body. As Brutus plots to disrupt the body politic of Rome, his own body plots against him.
The narrative arc of Julius Caesar presents numerous intersections between public and private life: intimate dreams predict catastrophic political violence, hushed conversations plot the future of Roman government, and—as Brutus declares above—even one's own bodily functions begin to rebel in parallel with the machinations of the treacherous senators who will strike at Caesar. Throughout the play, Shakespeare uses small moments like this to illustrate how, for the class of celebrity-rulers in charge of the fate of Rome, even the smallest moments of private life are dragged out into the open and laden with political implication.
In Act 2, Scene 1, Brutus attempts to recruit Licarius to the conspiracy against Caesar. Though Ligarious is ill, he feels eager to join the cause. He goes so far as to compare, using simile, Brutus's recruitment efforts to the work of a spiritual healer:
Brave son, derived from honorable loins,
Thou like an exorcist hast conjured up
My mortified spirit. Now bid me run,
And I will strive with things impossible,
Yea, get the better of them. What’s to do?
A piece of work that will make sick men whole.
Ligarius feels that Brutus's invigoration of his political sentiments is like the work of an exorcist reviving an ailing soul. Picking up on Ligarius's own simile, Brutus then extends it into a metaphor for the entire plot against Caesar: it is a work of healing in itself, to "make sick men whole."
Throughout Julius Caesar, Shakespeare conveys the urgency of Rome’s political scheming—and the depth of passion felt by all sides—in the language of life (and healing) and death (and dying). Brutus articulates the work at hand, to assassinate Caesar, in terms of a pun on the notion of a "body politic." Caesar threatens Rome like disease threatens a body, and to stop Caesar is to heal Rome of its sickness. Conflating on the intimate matter of bodily health with the public affair of political struggle, Brutus transforms his cause into a mortal effort to save Rome itself.
In Act 2, Scene 1, Cassius and Brutus lay the groundwork for their effort to defeat Caesar and remove him as a threat to the Roman Republic. Brutus balks at the prospect of more bloodshed when Cassius proposes eliminating Mark Antony in addition to Caesar himself, metaphorically comparing Antony to the "limb" of Caesar in order to advocate against his murder:
Our course will seem too bloody, Caius Cassius,
To cut the head off and then hack the limbs,
Like wrath in death and envy afterwards;
For Antony is but a limb of Caesar.
Let’s be sacrificers, but not butchers, Caius.
For Brutus, killing Antony alongside Caesar would be needlessly brutal. Caesar is the "head"—the figurative brains—of his political operation, whereas as Antony is only a "limb"—a mere follower. To cut off the head and hack off the limbs of a body is an excessively gruesome endeavor, and Brutus warns against descending from political assassination into rote butchery.
As he does throughout the play, Shakespeare uses metaphor to equate the function of Caesar and his allies as part of a body politic with the actual parts of a human body. The story of Caesar, of course, will eventually literalize part of this comparison: Brutus compares the process of removing Caesar as a political threat to the act of murdering, or beheading, a body—a process that will shortly hereafter require Caesar's actual murder.
Julius Caesar presents a lengthy exploration of the role of morality in political decision making—the audience witnesses characters of the play selectively disregarding any sense of morality in order to further their political causes. In Brutus's speech above, he makes a moral, if twisted, case for sparing Antony's life: murder is justifiable toward certain political ends. He describes Caesar's death as a necessary "sacrifice," but any more bloodshed would be gratuitous and irredeemable.
In Act 2, Scene 1, a sleepless Brutus mulls over the plot against Caesar in his orchard. In metaphorical language, he muses over Caesar's rise to power:
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.
Brutus compares humility to a ladder that a young and ambitious politician would use to climb the ranks, only to cast aside once they are ready to seize power for themselves. Humility, in other words, is a strategic device—a tool used to disguise one’s plans until the time has come to be overtly (and even disastrously) ambitious. Such is the accusation Brutus levies against Caesar.
It is concerning that a virtue such as humility could be used to such manipulative ends, although this is altogether fitting with Shakespeare's exploration of the morality of politics throughout Julius Caesar: politicians—such as Caesar, and Brutus himself—may behave morally, but only in order to gain more power. One's honor is at the heart of one's identity in the play, and Brutus's accusation that Caesar would behave with honorable humility and gain respect in order to better manipulate his supporters thus strikes at the heart of Caesar's legitimacy as a politician and as a man.
Conquest is all a matter of timing. In Act 4, Scene 3, as Brutus and Cassius discuss how best to face the armies of Antony and Octavius in battle, Brutus uses the metaphor of the ocean's tides to emphasize the importance of striking at the right moment:
There is a tide in the affairs of men
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves
Or lose our ventures.
The political struggles of humanity move like the tides in the ocean: if you act at “high tide,” when the timing is right, success will follow; if you miss this moment, you doom yourself to life in the “low tide” of “miseries.” Brutus argues that the tide is high for Cassius and himself, and that they should therefore take action and march to meet their rivals at Philippi.
Throughout Julius Caesar, Shakespeare explores whether humans have agency in determining the course of their own lives—and, indeed, the course of Rome itself. To a certain extent, the events of the play—and especially Caesar's assassination—seem predetermined, predicted at every turn by omens, soothsayers, and foreshadowing. In this metaphor, Brutus's invocation of the tide seems to imply that "human affairs" mimic the give-and-take motion of the sea: the sentiments, ambitions, and opportunities of the moment will rise only to eventually recede and be replaced by some other focus in cyclical fashion. Though this momentum may be outside Brutus or his peers' control, his speech would suggest that he nonetheless has the agency to decide whether or not to take advantage of the situation.
In Act 5, Scene 1, Cassius, Brutus, and Antony trade insults as their armies face each other in battle. Cassius makes an allusion to Hyblean honeybees as he mocks Antony for his bluster:
The posture of your blows are yet unknown,
But, for your words, they rob the Hybla bees
And leave them honeyless.
Not stingless too.
O yes, and soundless too,
For you have stolen their buzzing, Antony,
And very wisely threat before you sting.
Hybla is an area of Sicily renowned for its bees. Cassius and Brutus use this allusion to insult Antony for his flowery language and lack of decisive action as a warrior: Antony has taken the “honey” from the Hybla bees and used it in his sweet speech, and has also “stolen their buzzing”: he makes a lot of noise with his words without any actual aggression, like a Shakespearean post-classical version of the idiom “all bark and no bite.” These jabs from Cassius and Brutus are direct attacks on Antony’s fitness as a soldier and political and military leader, reflecting both Cassius's preoccupation with status and Brutus's preoccupation with honor.
In Act 5, Scene 5, as Brutus faces defeat, he asks Dardanius to kill him. Relaying Brutus's final request to Clitus, the pair observe Brutus's grieving form through metaphor:
What ill request did Brutus make to thee?
To kill him, Clitus. Look, he meditates.
Now is that noble vessel full of grief,
That it runs over even at his eyes.
Brutus has become a water vessel: he is so full of grief that he begins to "overflow" with it. In the midst of this tragic scene, Brutus weeps because there is no where else for the grief to go. The extent of this emotion, and Brutus's deadly request to Dardanius, cements him as the true tragic hero at the center of Julius Caesar. He has lost everything: his wife, Portia, has committed suicide, his political ambitions have been vanquished, and he faces immanent military defeat. For the politicians at the center of Julius Caesar, self-worth is entirely determined by political standing and military success—any defeat has existential proportions and questions the person's very right to exist. As he overflows with grief, Brutus finds the only honorable way out to be his death even as his companions urge him to continue on.