In Chapter 6, two gentlemen exchange stories in Nicholas's presence, both of which are allegorical in their own right. In between stories, the gentlemen have a philosophical conversation, specifically discussing the Tale of the Five Sisters of York, told by the first gentleman. During their discussion, one gentleman alludes to Greek mythology:
To remember happiness which cannot be restored is pain, but of a softened kind. Our recollections are unfortunately mingled with much that we deplore, and with many actions which we bitterly repent; still in the most chequered life I firmly think there are so many little rays of sunshine to look back upon, that I do not believe any mortal (unless he had put himself without the pale of hope) would deliberately drain a goblet of the waters of Lethe, if he had it in his power.
This passage includes an allusion to the River Lethe, one of several rivers that flow into the Underworld in Greek mythology. Drinking the waters of the River Lethe was said to erase a person's memories. The gentleman, reacting to the tragic story of the sisters, asserts that no person, regardless of what they suffer in life, would choose to forget everything rather than remember happiness.
Dickens often references Shakespeare's works in Nicholas Nickleby, both directly and indirectly. Note the following description Dickens gives as a preface to Chapter 12:
Whereby the Reader will be enabled to trace the further course of Miss Fanny Squeers’s Love, and to ascertain whether it ran smoothly or otherwise.
This is a reference to the famous line from A Midsummer Night's Dream, spoken by Lysander to Hermia: "the course of true love never did run smooth." While Lysander speaks this line to Hermia in earnest, Dickens injects his own characteristic irony into the line by adding "or otherwise" to the end. This alludes to the fact that Miss Fanny Squeers's "love" story will have an unsatisfactory conclusion, perhaps because that "true love" is unrequited.
Dickens includes several such indirect references in Nicholas Nickleby, quoting Shakespeare throughout. References to the famous playwright are plentiful within the Western literary canon; Dickens is no exception compared to his contemporaries. The choice to include so many Shakespeare references is, however, intentional: Dickens uses these references as a form of literary credentialing; a means by which to establish authority amongst contemporaries and readers. If an author can reference the literary canon in new and clever ways within their own work, said author's abilities and intellect often accrue greater critical acclaim. Dickens alludes to Shakespeare throughout Nicholas Nickleby in an effort to elevate his status and acclaim as an author, adding credibility to any moral grandstanding.
In the following passage from Chapter 38, Mr. Squeers complains about Smike's "ungrateful" behavior, utilizing both metaphor and allusion to do so:
Mrs Squeers has been his mother, grandmother, aunt, – Ah! and I may say uncle too, all in one. She never cottoned to anybody except them two engaging and delightful boys of yours, as she cottoned to this chap. What’s my return? What’s come of my milk of human kindness? It turns into curds and whey when I look at him.
When Mr. Squeers refers to the "milk of human kindness" in this passage, Dickens is alluding to a prominent passage from Macbeth (Act I, scene 5, lines 15-17): "Yet I do fear thy nature. / It is too full o’ th’ milk of human kindness."
Mr. Squeers also utilizes metaphor in this passage, angrily asserting that Smike is ungrateful to himself and Mrs. Squeers for all that they have done for him. Mr. Squeers declares that his "milk of human kindness," or his compassion, has curdled into bitterness and anger (curds and whey) due to Smike's alleged behavior. Mr. Squeers feels that Smike owes him something, despite the fact that Squeers has been abusing and taking advantage of Smike for years. This entitlement is a strong feature of Mr. Squeers's character.
In the following passage from Chapter 46, Nicholas and Charles discuss Madeline, whom Charles does not realize Nicholas has already met. The narrator includes a bit of apt allusion in the passage, using the reference to describe Nicholas' shell-shocked reaction:
‘She is the lady I speak of,’ said brother Charles. Like the famous parrot, Nicholas thought a great deal but was unable to utter a word.
The phrase "like the famous parrot" above refers to a story from Aesop's Fables. In one tale from the anthology, a man buys a parrot because of its apparent eloquence, only to grow aggravated once he discovers that the bird cannot speak more than a single sentence. In the above passage, the narrator likens Nicholas to this parrot, using allusion to emphasize the true extent of Nicholas's shock.
The above allusion is one of many peppered throughout Nicholas Nickleby. Dickens alludes heavily to a wide range of culturally significant works and figures in the novel, from politicians to writers to poets. While this may provide some difficulty for modern readers when attempting to parse the novel's meaning, it does establish the narrator/writer as familiar with Western literary canon. This frequency of allusion may be Dickens's effort to establish ethos, or a kind of moral credibility with his audience—after all, many readers will by nature interpret intellectual authority as moral authority.