in Richard III, in Julius Cæsar, in Macbeth, in Cymbeline, in The Winter's Tale (the oracle), the supernatural beings, however diverse their nature, are alike in certain respects. They have sources of information denied to mortals. They are free from the encumbrances of mortal frailty, and so far as they take upon themselves the responsibility of speech and action, they possess virtual infallibility. The fairies of A Midsummer-Night's Dream make ludicrous blunders, it is true, and show a plentiful lack of wisdom, but this is a comic phantasy. In The Tempest again, the spirits are not free agents; it is Prospero in whom the supernatural power is really centered. But in serious actions Shakespeare regularly represents the utterances of supernatural beings, when they appear on their own initiative, as possessing two characteristics: perfect truth (though the form of the statement may be such as to mislead erring mortals), and, so far as the purpose of the speaker is concerned, sufficiency for the end proposed.
The ghost, therefore, may be regarded, within reasonable limitations, as sharing this infallibility. He has passed beyond the possibility of mortal errors of judgement; he has sources of knowledge in which mortals have no part. He returns to earth from purgatory, not from heaven, for that would be incongruous with his demand for revenge; not from hell, for that would be incompatible with Hamlet's duty to
