(1) We remember that Macbeth has already seen one hallucination, that of the dagger; and if we failed to remember it Lady Macbeth would remind us of it here: 

This is the very painting of your fear;
This is the air-drawn dagger which, you said,
Led you to Duncan.

(2) The Ghost seems to be created by Macbeth’s imagination; for his words,

now they rise again
With twenty mortal murders on their crowns,

describe it, and they echo what the murderer had said to him a little before,

Safe in a ditch he bides
With twenty trenched gashes on his head.

(3) It vanishes the second time on his making a violent effort and asserting its unreality: 

Hence, horrible shadow! 
Unreal mockery, hence!

This is not quite so the first time, but then too its disappearance follows on his defying it: 

Why what care I?  If thou canst nod, speak too.

So, apparently, the dagger vanishes when he exclaims, ’There’s no such thing!’

(4) At the end of the scene Macbeth himself seems to regard it as an illusion: 

                        My strange and self-abuse
     Is the initiate fear that wants hard use.

(5) It does not speak, like the Ghost in Hamlet even on its last appearance, and like the Ghost in Julius Caesar.

(6) It is visible only to Macbeth.

I should attach no weight to (6) taken alone (see p. 140).  Of (3) it may be remarked that Brutus himself seems to attribute the vanishing of Caesar’s Ghost to his taking courage:  ’now I have taken heart thou vanishest:’  yet he certainly holds it to be real.  It may also be remarked on (5) that Caesar’s Ghost says nothing that Brutus’ own forebodings might not have conjured up.  And further it may be asked why, if the Ghost of Banquo was meant for an illusion, it was represented on the stage, as the stage-directions and Forman’s account show it to have been.

On the whole, and with some doubt, I think that Shakespeare (1) meant the judicious to take the Ghost for an hallucination, but (2) knew that the bulk of the audience would take it for a reality.  And I am more sure of (2) than of (1).

INDEX

The titles of plays are in italics.  So are the numbers of the pages containing the main discussion of a character.  The titles of the Notes are not repeated in the Index.

Aaron, 200, 211.

Abnormal mental conditions, 13, 398.

Accident, in tragedy, 7, 14-16, 26, 28;
  in Hamlet, 143, 173;
  in Othello, 181-2;
  in King Lear, 253, 325.

Act, difficulty in Fourth, 57-8;
  the five Acts, 49.

Action, tragic, 11, 12, 31;
  and character, 12, 19;
  a conflict, 16-19.

Adversity and prosperity in King Lear, 326-7.

Albany, 297-8.