The strong French sympathies of the Swiss in the Franco-Prussian War as well as the prospect for a pension for his wife in the case of his death led to his speedy resignation.

[citation needed] His main work, the Geschichte des Materialismus is a didactic exposition of principles rather than a history in the proper sense.

Adopting the Kantian standpoint that we can know nothing but phenomena, Lange maintained that neither materialism nor any other metaphysical system has a valid claim to ultimate truth.

In Lange's Logische Studien, which attempts a reconstruction of formal logic, the leading idea is that reasoning has validity in so far as it can be represented in terms of space.

Lange was sympathetic towards the rallying of workers' unions as he believed them to be a crucial step towards the egalitarian society he details in a large variety of his published works.

[8] When Lange was twenty, he became an official member of the German Social Democratic Party, otherwise known as the SPD, and would swiftly rise to prominence primarily as a result of his dedication to improving workers’ well-being and education.

His loyalty to his ideals enabled him to accrue a great following of supporters that believed in his idea of a peaceful revolution, giving him a powerful basis for his later movements and publications.

The association was founded by Ferdinand Lassalle and the two would frequently engage in debate in regard to their differing stances on the role held by the state in supporting significant social change.

He served as a primary editor for the party's newspaper, enabling him to shape the public's perception of socialism while engaging in meaningful debates regarding the organization's goals.

During this time Lange was an outspoken advocate for the use of revolutionary violence, as he believed it was necessary to achieve an equitable society, however, he would reconsider his stance following the failure of the revolution.

Lange had a fundamental belief that the primary concern for the working class lay in its inaccessibility to affordable living based on the minimal wages being provided.

[9] Thomas believed that an increase in food availability should be the first and foremost concern when attempting to raise the standing of the working class, as the primary constraint is in the struggle for mere existence.

While Malthus' notions would be most commonly interpreted as supportive of capitalism and widely disparaged in Germany, Lange had a unique understanding of his argument that led him to conclude that bolstering the lower class's living conditions must be brought through a fundamental change in the legal system.