This chapter examines the so-called “materialism controversy,” one of the most important intellectual disputes of the second half of the nineteenth century. The dispute began in the 1850s, and its shock waves reverberated until the end of the century. The main question posed by the materialism controversy was whether modern natural science, whose authority and prestige were now beyond question, necessarily leads to materialism. Materialism was generally understood to be the doctrine that only matter exists and that everything in nature obeys only mechanical laws. If such a doctrine were true, it seemed there could be no God, no free will, no soul, and hence no immortality. These beliefs, however, seemed vital to morality and religion. So the controversy posed a drastic dilemma: either a scientific materialism or a moral and religious “leap of faith.” It was the latest version of the old conflict between reason and faith, where now the role of reason was played by natural science.
