How did Shakespeare use the mixed metaphor “a sea of troubles” in Hamlet?

In William Shakespeare’s Hamlet, the phrase "a sea of troubles" appears in the character's famous soliloquy, where he asks whether it is nobler to "take arms against a sea of troubles" and by opposing them, end them.12

This expression is classified as a mixed metaphor because it combines two incongruous elements: the act of taking up arms (a military metaphor) and the act of fighting against a sea (a vast, fluid, and uncontrollable force). Logically, one cannot literally "take arms" or fight against a body of water; a more consistent metaphor might have used a word like "host" to represent an army.13

However, Shakespeare uses this rhetorical device with great effectiveness. By pairing the military imagery of "taking arms" with the vast, overwhelming nature of a "sea," he vividly conveys the sheer scale and inescapable intensity of Hamlet’s suffering. Rather than being a mere error, the mixed metaphor serves to emphasize the futility and magnitude of the challenges Hamlet faces.1