Optimism
Pangloss's first lesson to Candide is that "there cannot possibly be an effect without a cause" and that "everything is made to serve an end." This encapsulates the doctrine of optimistic determinism. If an omniscient, omnipotent God made the world according to his design, then the presence of evil would imply a malice toward his own creatures. Believers in the Christian faith responded to this theological problem by applying a rational understanding to the phenomenon of evil, using an analysis of cause and effect to justify every particular instance of evil in terms of the eventual, broader good to emerge from it. "Private misfortunes make for public welfare," Pangloss concludes.
Free Will
Martin cites free will as the key distinction between men and animals. The concept and possibility of social progress depend on the freedom of men to determine their own fate, both individual and collective. If men are to move beyond the barbarism to which so many of the characters bear witness, they must utilize their power of free will to "cultivate our garden," as Voltaire famously declares in the ultimate chapter. In other words, people must band together, contribute to the larger social good, and shape the future contours of civilization in a positive manner.
Evil
Is evil an intrinsic part of creation or a simple matter of perspective, an arbitrary and random quirk of fate? This ongoing philosophical debate between Candide the optimist and Martin the Manichaean is in fact never resolved in either character's favor. On the one hand, Pangloss's contention that the phenomenon of evil can be rationalized through an intricate web of cause and effect is thoroughly satirized and discredited by Voltaire; on the other, the evidence of man's unrelenting capacity for "lies, fraud, treachery, ingratitude, inconstancy, envy, ambition, and cruelty" proves incontrovertible and points to a sense of pervasive malice in the world. Evil is not exactly necessary but nor is it eliminable.
Pity
The tragedies sustained by each of the main characters could logically lead to an attitude of self-pity and resignation to the inevitability of misfortune. But the Old Woman, despite her own hardships, is the one character to renounce this attitude, instead challenging Miss Cunégonde and Candide to find someone who does not consider himself "the most wretched of mortals." Candide is in some respects a cautionary tale against the excesses of pity and the moral paralysis that it engenders, as many of its characters appear to languish in a world where adversity is an intractable rather than mutable condition.
Pleasure vs. Criticism
The enjoyment of music, painting and literature comes under attack first by the theater critic at Miss Clairon's performance and later by Senator Pococurante. Dismissed as sentimental or frivolous, art is a pleasure reserved only to those still naïve or earnest enough to appreciate it and take it at face value, such as Candide. The overarching implication is an opposition between pleasure and criticism. Voltaire seems to suggest that the faculty of judgment and discrimination has become so overly rigorous that it has destroyed the possibility of any intuitive emotional or purely aesthetic response to art. As a result, the only pleasure to be had derives paradoxically from trashing (in a critical sense) precisely that which is intended to bring the spectator pleasure.
