---
title: "Materialism controversy"
chunk: 1/6
source: "https://en.wikipedia.org/wiki/Materialism_controversy"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:39:45.902602+00:00"
instance: "kb-cron"
---

The materialism controversy (German: Materialismusstreit) was a public debate in the mid-19th century about how new developments in the natural sciences might affect existing worldviews. During the 1840s, a new form of materialism emerged, shaped by advances in biology and the decline of idealistic philosophy. This form of materialism sought to explain human beings and their behavior through scientific methods. The central question of the debate was whether scientific discoveries were compatible with traditional ideas such as the existence of an immaterial soul, a personal God, and human free will. The discussion also touched on deeper philosophical issues, such as what kind of knowledge a materialist or mechanical view of the world could offer.
In his Physiologische Briefe from 1846, zoologist Carl Vogt argued that mental processes were entirely physical, famously stating that "thoughts stand in the same relation to the brain as bile does to the liver or urine to the kidneys." In 1854, the physiologist Rudolf Wagner criticized this view in a speech to the Göttingen Naturalists' Assembly. He argued that religious belief and science belonged to separate areas of understanding, and that natural science could not answer questions about God, the soul, or free will.
Wagner’s comments were strongly worded, accusing materialists of trying to undermine spiritual values. His attacks sparked sharp responses from Vogt and others. The materialist position was later defended by figures such as physiologist Jakob Moleschott and physician Ludwig Büchner, brother of writer Georg Büchner. Supporters of materialism saw themselves as opposing what they viewed as outdated philosophical, religious, and political ideas. While their approaches varied, they found growing support among the middle classes. The idea of a scientific worldview became an important feature in the broader cultural debates of the late 19th and early 20th centuries.

== Development of natural scientific materialism ==

=== Emancipation of biology ===

The rise of popular materialism in the mid-19th century was partly driven by growing criticism of romantic and idealist natural philosophy. This critique became widespread after 1830 and influenced science, philosophy, and politics alike.
One major scientific development that supported this shift was the emergence of cell theory, founded by botanist Matthias Jacob Schleiden. In 1838, Schleiden published a study on plant development in which he identified the cell as the basic unit of all plant life and emphasized the role of the cell nucleus, discovered in 1831, in plant growth. This theory marked a turning point in botany, which had previously focused mainly on describing the external forms of plants. Schleiden combined his scientific findings with a strong critique of idealist natural philosophy. He argued that scientific knowledge must be based on direct observation, unlike the speculative systems of earlier philosophers. According to him, abstract theorizing not grounded in evidence had to be rejected.
Schleiden’s call for a more scientific and observation-based approach soon influenced other areas of biology. In 1839, Theodor Schwann published Microscopic Investigations on the Similarity in Structure and Growth of Animals and Plants, extending Schleiden’s ideas to animals. Schwann proposed that all living things are made of cells and that tissues and organs develop through cell growth and reproduction. Building on this, physician Rudolf Virchow later summarized the idea by stating: “Life is essentially cellular activity". These insights laid the foundation for a scientific understanding of life, which materialist thinkers would build upon in the following years.

=== Turning away from idealistic philosophy ===

At the same time, a broader critique of German idealism began to take shape, especially in the years before the 1848 revolutions (the Vormärz period). While many scientists still opposed materialism, criticism of idealist philosophy became more common, particularly among younger intellectuals.
One of the most influential figures in this movement was Ludwig Feuerbach, whose 1841 work The Essence of Christianity had a major impact. Feuerbach had studied under Georg Wilhelm Friedrich Hegel in Berlin and initially followed the idealist tradition. However, by the late 1830s, he began to reject it. Like other young Hegelians, he grew dissatisfied with idealism's abstract systems and its alignment with conservative politics. In 1839, Feuerbach openly criticized Hegel's philosophy. While he acknowledged its internal logic, he argued it was too far removed from the natural world and human experience. Feuerbach believed that philosophy should be grounded in the senses and in the physical reality of nature and humanity. As he put it: “All speculation that seeks to go beyond nature and man is vain. Although Feuerbach was not a scientist, his ideas about grounding knowledge in human experience and nature echoed the goals of the new biology. He promoted a type of anthropology—a theory of humanity based on lived experience—rather than a speculative or purely scientific approach.
Feuerbach’s most controversial ideas came from his critique of religion. He argued that religion was not a reflection of divine truth, but a projection of human hopes and needs. God, he claimed, was not an external being, but a creation of the human mind. While he did not reject religion entirely, he believed its value lay in its psychological and emotional function, not in metaphysical truth. Religious doctrines, he argued, could not be proven through reason or science—they were, in his view, products of imagination rather than reality.

== Carl Vogt and the political opposition ==