As Voltaire himself described it, the purpose of Candide was to "bring amusement to a small number of men of wit". The author achieves this goal by combining his sharp wit with a fun parody of the classic adventure-romance plot. Candide is confronted with horrible events described in painstaking detail so often that it becomes humorous. Literary theorist Frances K. Barasch described Voltaire's matter-of-fact narrative as treating topics such as mass death "as coolly as a weather report". The fast-paced and improbable plot—in which characters narrowly escape death repeatedly, for instance—allows for compounding tragedies to befall the same characters over and over again. In the end, Candide is primarily, as described by Voltaire's biographer Ian Davidson, "short, light, rapid and humorous".
Behind the playful façade of Candide which has amused so many, there lies very harsh criticism of contemporary European civilization which angered many others. European governments such as France, Prussia, Portugal and England are each attacked ruthlessly by the author: the French and Prussians for the Seven Years' War, the Portuguese for their Inquisition, and the British for the execution of John Byng. Organised religion, too, is harshly treated in Candide. For example, Voltaire mocks the Jesuit order of the Roman Catholic Church. Aldridge provides a characteristic example of such anti-clerical passages for which the work was banned: while in Paraguay, Cacambo remarks, "[The Jesuits] are masters of everything, and the people have no money at all …". Here, Voltaire suggests the Christian mission in Paraguay is taking advantage of the local population. Voltaire depicts the Jesuits holding the indigenous peoples as slaves while they claim to be helping them.
The main method of Candide's satire is to contrast ironically great tragedy and comedy. The story does not invent or exaggerate evils of the world—it displays real ones starkly, allowing Voltaire to simplify subtle philosophies and cultural traditions, highlighting their flaws. Thus Candide derides optimism, for instance, with a deluge of horrible, historical (or at least plausible) events with no apparent redeeming qualities.
A simple example of the satire of Candide is seen in the treatment of the historic event witnessed by Candide and Martin in Portsmouth harbour. There, the duo spy an anonymous admiral, supposed to represent John Byng, being executed for failing to properly engage a French fleet. The admiral is blindfolded and shot on the deck of his own ship, merely "to encourage the others" (French: pour encourager les autres, an expression Voltaire is credited with originating). This depiction of military punishment trivializes Byng's death. The dry, pithy explanation "to encourage the others" thus satirises a serious historical event in characteristically Voltairian fashion. For its classic wit, this phrase has become one of the more often quoted from Candide.
Voltaire depicts the worst of the world and his pathetic hero's desperate effort to fit it into an optimistic outlook. Almost all of Candide is a discussion of various forms of evil: its characters rarely find even temporary respite. There is at least one notable exception: the episode of El Dorado, a fantastic village in which the inhabitants are simply rational, and their society is just and reasonable. The positivity of El Dorado may be contrasted with the pessimistic attitude of most of the book. Even in this case, the bliss of El Dorado is fleeting: Candide soon leaves the village to seek Cunégonde, whom he eventually marries only out of a sense of obligation.
Another element of the satire focuses on what William F. Bottiglia, author of many published works on Candide, calls the "sentimental foibles of the age" and Voltaire's attack on them. Flaws in European culture are highlighted as Candide parodies adventure and romance clichés, mimicking the style of a picaresque novel. A number of archetypal characters thus have recognisable manifestations in Voltaire's work: Candide is supposed to be the drifting rogue of low social class, Cunégonde the sex interest, Pangloss the knowledgeable mentor and Cacambo the skilful valet. As the plot unfolds, readers find that Candide is no rogue, Cunégonde becomes ugly and Pangloss is a stubborn fool. The characters of Candide are unrealistic, two-dimensional, mechanical, and even marionette-like; they are simplistic and stereotypical. As the initially naïve protagonist eventually comes to a mature conclusion—however noncommittal—the novella is a bildungsroman, if not a very serious one.
Gardens are thought by many critics to play a critical symbolic role in Candide. The first location commonly identified as a garden is the castle of the Baron, from which Candide and Cunégonde are evicted much in the same fashion as Adam and Eve are evicted from the Garden of Eden in the Book of Genesis. Cyclically, the main characters of Candide conclude the novel in a garden of their own making, one which might represent celestial paradise. The third most prominent "garden" is El Dorado, which may be a false Eden. Other possibly symbolic gardens include the Jesuit pavilion, the garden of Pococurante, Cacambo's garden, and the Turk's garden.
These gardens are probably references to the Garden of Eden, but it has also been proposed, by Bottiglia, for example, that the gardens refer also to the Encyclopédie, and that Candide's conclusion to cultivate "his garden" symbolises Voltaire's great support for this endeavour. Candide and his companions, as they find themselves at the end of the novella, are in a very similar position to Voltaire's tightly knit philosophical circle which supported the Encyclopédie: the main characters of Candide live in seclusion to "cultivate [their] garden", just as Voltaire suggested his colleagues leave society to write. In addition, there is evidence in the epistolary correspondence of Voltaire that he had elsewhere used the metaphor of gardening to describe writing the Encyclopédie. Another interpretative possibility is that Candide cultivating "his garden" suggests his engaging in only necessary occupations, such as feeding oneself and fighting boredom. This is analogous to Voltaire's own view on gardening: he was himself a gardener at his estates in Les Délices and Ferney, and he often wrote in his correspondence that gardening was an important pastime of his own, it being an extraordinarily effective way to keep busy.