All life forms are interconnected.

One of the story’s premises is that all life forms on earth, no matter how large or small, are connected. Travis explains this interconnected ecosystem as he describes a food web that spans generations. The death of a single mouse, he tells the group, may lead to the end of the mouse’s family line. This, in turn, may eventually lead to a shortage of food for the foxes that feed on mice. That scarcity might then affect animals further up the food chain, leading boars, lions, and even human beings to starve. Ultimately, the death of that single mouse, given enough time, can lead to the extinction of a species or the complete elimination of a human civilization.

The story’s shocking outcome emphasizes this point, confirming the theory that Travis has expounded; his concerns have not been misplaced. The seemingly insignificant butterfly that Eckels has accidentally killed was somehow the cause of countless chains of events. The butterfly’s life had been of extraordinary significance to time, and its death changed language and political regimes in the future. Put simply, it may have taken 60 million years for the connection to become clear, but the death of that tiny life in the past has, indeed, altered the course of a human civilization. A dictator has been elected president of the United States.

Individual actions have tremendous social significance.

One of the more disturbing ideas of “A Sound of Thunder” is its suggestion that every individual’s actions can have incredible social significance, no matter how insignificant those actions may seem. Independent actions are not isolated from other events, nor is the behavior of individuals independent of social effects. Bradbury’s narrative explores the relationship between individualism and social responsibility by examining the flaws and behaviors of Eckels, an individual who has little concern for the social group. Eckels’s carelessness, failure to understand himself, and questioning disregard for rules put the group in jeopardy and, ironically, lead to an authoritarian future under Deutscher.

Eckels’s individualism is emphasized throughout the story. He wants a personal guarantee for his own safety. He demands to know why they have strict rules about what they can kill, where they can walk, and how animals are selected for the hunt. His worries and interests—although he is but one member of a hunting party of six—never indicate social concern. Then, at the moment the group is to act together as a cohesive unit to achieve its goals, at the moment Eckels is needed to support and protect that group, true to his individualistic character, he abandons them in fear.

In the end, Eckels’s individual actions and failure to act with his immediate social group in mind affect the entire social system. Eckels’s individual actions and his neglect to consider the welfare of this immediate social group have repercussions that extend beyond his personal sphere, ultimately impacting the entire social and political system. The demise of American democracy, rooted in individualism, is evident in the context of the story’s presidential election and the broader ideological struggle between democracy and fascism.

Wealth cannot solve every issue.

From the story’s outset, Bradbury draws attention to the limitations of wealth as it cannot provide security. Eckels is about to spend ten thousand dollars on his hunting adventure, and, as might be expected given the cost, he asks for a guarantee of his safety. He is told that there are no guarantees, save that there will be dinosaurs. He is then told that multiple clients, likely as wealthy as himself, have died on similar ventures. Money does not offer protection or safety.

Later, following the crisis with the dinosaur, Travis is furious, in part because of the fine they will face and the threat that they may lose the franchise. Eckels’s response is quick as Travis threatens to abandon him to the past: “I’ll pay anything. A hundred thousand dollars!” The only reason Eckels winds up returning to the present is Lesperance’s insistence, not the offer of money; it cannot supply needed penitence.

Even at the story’s conclusion, Eckels desperately pleads to travel back to reverse his own actions, restoring the butterfly to life. Nothing, of course, can be done. The damage is irreversible, and his wealth cannot restore the world to what it was.