Existential Stagnation
Almost all of the characters struggle with the monotonous quality of their lives out in the Russian countryside: even by the end of the play, there are practically no changes whatsoever. There does seem to be a moment when there is the potential for significant change—the climax with the two shots Uncle Vanya takes at the pompous professorial epicenter of his misery—but the two shots miss the professor, so life at the end of the play is pretty much consistent with how it is was at the beginning. The lesson is that nearly everyone is doomed to lose the fight against entropy; life is always stagnant, and the mere desire for change is simply not enough to stem the tide.
Perception and Delusion
Most of the characters have trouble truly seeing themselves or the nature of others. For example, the professor is fairly unremarkable; he is neither the great intellect he believes himself to be, nor the supreme architect of pretension that Vanya accuses him of being. It is in between these gaps of extremities that the play examines the themes of perception and delusion. The professor may not be entirely deluded; he may genuinely believe in his greatness. He certainly acts it, and yet the evidence would certainly seem to suggest otherwise. Vanya sums up this contradiction succinctly: “When people have no real life, they live on their illusions.” Vanya himself lives on the illusion that he had the potential to be a Schopenhauer or a Dostoevsky, were it not for his worthless laboring for Serebryakov.
The Corrosive Effects of Time
A recurring theme in many of Chekhov's plays is how time seems to pass without notice until one day a character wakes up and see how much of it was wasted. Sonya has lost half a dozen years of her life wrapped in an unrequited love for Astrov. Vanya looks back with regret on having a chance to marry Helen and letting it slip by, as well as wasting a quarter century in the service of the thankless professor. His mother has reached the half-century mark scribbling into notebooks with a look of complete vacancy written on her face, and Astrov is now past the point of settling down or staving off deforestation.
The Nature of Country Life
Chekhov doesn't have a lot of nice things to say about life in the Russian countryside. Older class distinctions have eroded, so the nature of work is now different. For the poorest, life is only a struggle and people cannot look past merely surviving. For the wealthy, life is idle and stultifying, stamping out individuality, ambition, and passion. Astrov calls this life stupid, tasteless, and second-rate; Sonya survives only by focusing on the afterlife. The characters acutely feel their restlessness and stagnation and thus pick fights, nurse grievances, and attempt seductions because there is simply nothing else meaningful to do.
The Value of Art
Chekhov implicitly suggests that art is redemptive but that it is sometimes difficult to access. The main example of this is when Helen, buoyed by her sincere interaction with Sonya, wonders if she could play the piano. She muses, "I feel like playing the piano. I'd like to play something now" (142), and, "It's been ages since I played anything. I'll play and cry, cry my eyes out like a silly girl" (143). Unfortunately, Serebryakov curtly tells Sonya he does not want Helen to play, and that is the end of that. It's a quiet, sad moment because it is the only time in the play that the bored, droll Helen asks to do something for herself alone, something that would elevate her out of this mundanity. When Serebryakov selfishly says no, Helen doesn't persist: she slips back to her listless self.
The Morality of Work
The critic Morris Freedman claims that Chekhov's short stories and plays are concerned with "the morality of work." Work is seen as something that gives value to life, making a person better because they have a focus. It isn't something that brings about glory or fame; rather, it has subtler impacts. Astrov labors diligently in his practice even when it distresses and enervates him; his other work on the forestry reservation makes him feel whole. Sonya and Vanya's labors on the estate are depicted as redemptive because they are one of the only ways to stave off complete despair due to the putative meaninglessness and harshness of life. Vanya works to forget and Sonya works to carry out her burdens in this sublunary life before being rewarded in heaven.
Nature
Chekhov laces the play with commentary on the environmental problems plaguing turn-of-the-century Russia. Through Astrov he laments the loss of trees, homesteads, animals, and concomitant health, beauty, and happiness. What's worse is that Russians have not built anything modern or useful to replace the wilderness; instead, everything is ravaged, empty, and worthless. He connects this to the characters' lack of fulfillment or meaning, but this message also stands as a critique of industrialization and environmental destruction.