In On The Origin of Species, Charles Darwin maintains that the struggle for survival ‘almost invariably will be most severe between the individuals of the same species, for they frequent the same districts, require the same food, and are exposed to the same dangers’. As individuals, we compete for the same resources, yet as a communal species we cooperate to acquire those resources. A myriad of thorny social conflicts inevitably emerge between our egotistic drive for self-preservation and our need to be interdependent. This fundamental tension between self-interests and communal obligations is the basis for much of the thematic opposition in London's work and is especially integral to his political writings.

Many post-Second World War American critics have tended to view London's emphasis on class conflict as outmoded, but the increasing wage inequality since the 1970s and the shrinkage of the middle class attest to its ongoing relevance. London's critique of class division is germane in the wake of the 2008 financial crisis and the growing financial inequity created by market economies and their capitalist oligarchs. He argued that capitalism created a social environment that supported avarice and exploitation, whereas socialism tended to encourage altruism and equity. The central conflicts of his political works are often linked to the contests for power between the egalitarian workers and the despotic plutocrats. He knew the path of evolution was variable, but, in his more sanguine appraisals, London viewed the movement toward increased combination and cooperation, along with the eventual emergence of socialism, as congruent with the general trend of biological evolution. London concurred with Darwin on the adaptive benefits of proto-socialist tendencies and believed that more cooperative forms of social organization would eventually win out in the long term – though this succession would mandate a prolonged and vehement struggle. He also acknowledged that modern nation state governments were prone to be exploited by the robust influence of our more brutish egotistical drives and totalitarian inclinations. His era's robber barons, political machines, and exploited workers, along with monopolistic corporate control and corruption, provided ample evidence of the primacy of our selfish instincts. ‘I should like to have socialism,’ he explained in 1901, ‘yet I know that socialism is not the very next step; I know that capitalism must live its life first ’ (CL i. 239).