What was Big Willy Shakes going for?
Horatio's name recalls the Latin term "orator," or "speaker." And that's just what Horatio does. He becomes the most sensible speaker in the play for Hamlet (and the audience) to trust. When there is a potential ghost roaming around the palace walls, whom do the guards call? Horatio. (Our money was on Ghostbusters.)
He evaluates the situation and gives a somewhat cryptic response to what's going down: “A mote it is to trouble the mind's eye.” Let's break it down. A mote is a speck. But Horatio is also punning “moat.” That's the type of ditch that surrounds a castle. He's saying that even the smallest speck (mote) of dust can irritate the eye. Translation: let's not just ignore this weird apparition. Even though it's probably no biggie, it could irritate the eye (castle) later.
He might also be giving a shout out to the Bible. In the King James Version, it says: “And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?” (Matthew 7:3). Perhaps Horatio is thinking that they should get the speck out of their eyes (that would be the ghost) before worrying about their enemies.
And it turns out he's right. The ghost's appearance launches Hamlet into a search for revenge. That, in turn, leads to a bunch of deaths. Pretty much every main character except for Horatio is dead by the end of the play. In waltzes Fortinbras, primed for war. He practically gets the Danish kingdom handed to him on a silver platter.
If only they had worried about the ghost and what he was doing coming back to haunt earth. If they hadn't have brushed him off, the Danes probably wouldn't find themselves in such a pretty pickle by the end of the play.
But here's the rub: Hamlet did listen to this phrase. The he spends the rest of the worrying about the ghost so much that he can't do anything else. He even repeats this phrase in the following scene. Hamlet says: Horatio! My father!—methinks I see my father. And when Horatio asks him, ”Where, my lord?” Hamlet replies: “In my mind's eye, Horatio.” (1.2.180-185).
Horatio is unnerved by the fact that his friend thinks he saw his dad. After all, that's exactly who he saw the night before. The only problem is, Hamlet's dad is dead. How could they see him? But then Hamlet says he saw him only in his imagination. Phew. Horatio thought he'd seen a ghost.
The idea of an eye in the mind was around long before Shakespeare. In fact Chaucer used the term “eye of his mind” in The Man of Law's Tale, which was written around 1390. So the idea at least was nothing new in Shakespeare's day.