A mote it is to trouble the mind's eye.
Act I, Scene 1 · Horatio
Context
Horatio describes the Ghost as a small irritant that nevertheless deeply disturbs perception and understanding, comparing it to a speck of dust in the eye.
Analysis
A 'mote' is a tiny particle, almost nothing, yet when it enters the eye it dominates your entire field of vision—you cannot see past it. By applying this image to the 'mind's eye,' Horatio suggests that the Ghost, however insubstantial, has lodged itself in their thinking and they cannot look away or think clearly. The metaphor also implies that the Ghost distorts rather than clarifies, making it harder to see the truth.
Essay Tip
Use this to argue that the Ghost functions as an obstruction to clear thinking, not a revelation—Horatio's metaphor shows that the supernatural doesn't enlighten the characters but instead traps their attention and clouds their judgment.