Certainly, I think that the exploitation of workers and the atmosphere in which workers like Jurgis toil resembles a "jungle." There is little sense of justice or fairness in this setting. Sinclair's title brings to light the cruelty of nature, the predatory setting, and the idea that a wilderness emerges where organisms live and perish without the machinery of nature stopping to reflect or ruminate. This might be the workplace that Progressivist thinkers like Sinclair see at the time. This is an arena where individuals are not respected nor treated with a sense of fairness, but rather exploited and used as means to ends as opposed to ends in of themselves. Such a construction has a profound impact on how workers' rights are seen, and until such an experience is validated, Sinclair's title becomes quite appropriate to describe such an atmosphere and setting.
The novel’s title symbolizes the competitive nature of capitalism; the world of Packingtown is like a Darwinian jungle, in which the strong prey on the weak and all living things are engaged in a brutal, amoral fight for survival. The title of the novel draws attention specifically to the doctrine of Social Darwinism, an idea used by some nineteenth-century thinkers to justify the abuses of wealthy capitalists. This idea essentially held that society was designed to reward the strongest, best people, while inferior people were kept down at a suitable level. By relating the story of a group of honest, hardworking immigrants who are destroyed by corruption and evil, Sinclair tries to rebut the idea of Social Darwinism, implying that those who succeed in the capitalist system are not the best of humankind but rather the worst and most corrupt of all.