In favour of (c) as against (a) I see no argument except that the words of Macduff almost repeat those of Margaret; and this fact does not seem to me to have much weight.  It shows only that Shakespeare might easily use the words in the sense of (c) if that sense were suitable to the occasion.  It is not unlikely, again, I think, that the words came to him here because he had used them many years before;[296] but it does not follow that he knew he was repeating them; or that, if he did, he remembered the sense they had previously borne; or that, if he did remember it, he might not use them now in another sense.

FOOTNOTES: 

[Footnote 294:  So in Holinshed, as well as in the play, where however ‘cousin’ need not have its specific meaning.]

[Footnote 295:  ‘May,’ Johnson conjectured, without necessity.]

[Footnote 296:  As this point occurs here, I may observe that Shakespeare’s later tragedies contain many such reminiscences of the tragic plays of his young days.  For instance, cf. Titus Andronicus, I. i. 150 f.: 

In peace and honour rest you here, my sons,

* * * * *

Secure from worldly chances and mishaps! 
Here lurks no treason, here no envy swells,
Here grow no damned drugs:  here are no storms,
No noise, but silence and eternal sleep,

with Macbeth, III. ii. 22 f.: 

                           Duncan is in his grave;

After life’s fitful fever he sleeps well;
Treason has done his worst:  nor steel, nor poison,
Malice domestic, foreign levy, nothing,
Can touch him further.

In writing IV. i.  Shakespeare can hardly have failed to remember the conjuring of the Spirit, and the ambiguous oracles, in 2 Henry VI. I. iv.  The ‘Hyrcan tiger’ of Macbeth III. iv. 101, which is also alluded to in Hamlet, appears first in 3 Henry VI. I. iv. 155.  Cf. Richard III. II. i. 92, ‘Nearer in bloody thoughts, but not in blood,’ with Macbeth II. iii. 146, ‘the near in blood, the nearer bloody’; Richard III. IV. ii. 64, ’But I am in So far in blood that sin will pluck on sin,’ with Macbeth III. iv. 136, ‘I am in blood stepp’d in so far,’ etc.  These are but a few instances. (It makes no difference whether Shakespeare was author or reviser of Titus and Henry VI.).]

NOTE FF.

THE GHOST OF BANQUO.

I do not think the suggestions that the Ghost on its first appearance is Banquo’s, and on its second Duncan’s, or vice versa, are worth discussion.  But the question whether Shakespeare meant the Ghost to be real or a mere hallucination, has some interest, and I have not seen it fully examined.

The following reasons may be given for the hallucination view: