The Foundations of a Changing Worldview
The decades preceding World War I witnessed one of the most profound intellectual transformations in human history. As the 19th century drew to a close, fundamental assumptions about the nature of reality that had guided scientific thought for centuries began to crumble under the weight of new discoveries and theoretical challenges. This period saw the emergence of revolutionary ideas that would permanently alter our conception of the universe, from the microscopic realm of quantum particles to the vast cosmic scales of relativity.
The traditional mechanical worldview inherited from Newton and Galileo, which had dominated scientific thinking since the Scientific Revolution, proved increasingly inadequate to explain new experimental findings. Scientists found themselves grappling with phenomena that defied classical explanations, leading to what historian Eric Hobsbawm described as “the crisis of the bourgeois world’s conceptual system.” This crisis affected not just physics and mathematics but extended into biology, psychology, and the social sciences, creating ripples that would eventually transform all areas of human knowledge.
The Collapse of Classical Physics
At the heart of this intellectual revolution stood the dramatic upheaval in physics. The late 19th century had been a period of remarkable progress in understanding electromagnetic phenomena, thermodynamics, and atomic theory. Yet by the 1890s, cracks began appearing in the edifice of classical physics. The Michelson-Morley experiment of 1887 delivered particularly devastating results, failing to detect the hypothesized “luminiferous ether” that physicists believed necessary to explain the propagation of light waves through empty space.
This ether had been conceived as an invisible, frictionless medium filling the universe, analogous to water carrying ocean waves. Its existence seemed essential to maintain the mechanical worldview that required all forces to act through direct contact rather than “action at a distance.” When repeated experiments consistently failed to detect Earth’s motion through this hypothetical medium, physicists faced a profound dilemma. As one contemporary observer noted, “Without it, we could not understand light, radiation, electricity or magnetism; perhaps there would be no such thing as gravitation.”
The resolution came from an unexpected quarter. In 1905, a young patent clerk named Albert Einstein published his special theory of relativity, which boldly dispensed with the ether concept altogether. Einstein’s work demonstrated that the laws of physics remain the same for all observers in uniform motion relative to one another, eliminating the need for any absolute frame of reference. This conceptual leap, combined with Max Planck’s earlier introduction of quantum theory in 1900, marked the beginning of a new era in physics where intuition and common sense no longer served as reliable guides to understanding nature.
The Crisis in Mathematics and Logic
Parallel to the revolution in physics, mathematics underwent its own profound transformation during this period. The late 19th century saw mathematicians confronting paradoxes and inconsistencies that challenged the very foundations of their discipline. Georg Cantor’s work on infinite sets revealed startling properties that defied conventional notions of number and size, prompting his famous remark: “I see it, but I don’t believe it.”
These developments led to what mathematician Nicolas Bourbaki later called “the great crisis of the foundations” (1900-1930). Traditional approaches based on geometric intuition proved inadequate for dealing with the new mathematical landscapes being explored. Curves without tangents, spaces with fractional dimensions, and other “pathological” constructions emerged, forcing mathematicians to reconsider what constituted valid mathematical reasoning.
Bertrand Russell and Alfred North Whitehead attempted to place mathematics on firmer logical ground with their monumental Principia Mathematica (1910-1913), while David Hilbert championed a formalist approach that treated mathematics as a game with defined rules but no necessary connection to physical reality. However, these efforts ultimately proved incomplete, as Kurt Gödel demonstrated in 1931 with his incompleteness theorems showing that any sufficiently powerful mathematical system contains statements that cannot be proven true or false within that system.
The Biological Revolution: From Darwin to Genetics
While physics and mathematics were undergoing their conceptual revolutions, biology experienced equally transformative changes. The rediscovery of Gregor Mendel’s work on inheritance in 1900 launched the new science of genetics, providing mechanisms for heredity that complemented and eventually transformed Darwin’s theory of evolution by natural selection.
This period saw intense debates between Mendelians, who emphasized discrete hereditary units (later called genes), and biometricians who focused on continuous variation. These scientific disagreements often carried ideological overtones, with some seeing in Mendel’s work support for eugenic policies while others emphasized environmental factors in development. As future Nobel laureate H.J. Muller declared in 1918, “I have never been interested in the genetics of abstract traits. My interest in genetics has always been primarily due to its bearing on human affairs—on the nature of man and the method of his improvement.”
The synthesis of Mendelian genetics with Darwinian evolution, along with Hugo de Vries’s concept of mutations, revitalized evolutionary biology while raising new questions about the nature and pace of biological change. These developments occurred alongside growing public interest in eugenics and the potential for applying biological principles to social problems, creating complex intersections between science and politics that would have profound consequences in the decades to follow.
The Psychological and Cultural Impact
The scientific revolutions of this period extended beyond laboratories and lecture halls, influencing broader cultural and intellectual trends. Sigmund Freud’s psychoanalysis, developed during these same years, challenged conventional notions of human rationality by emphasizing unconscious drives and childhood experiences. In the arts, movements like Cubism and atonal music paralleled the breakdown of traditional perspectives in science.
The separation of scientific understanding from everyday intuition created what one observer called “a psychological abyss.” As Russell noted, mathematics had become “a subject in which we never know what we are talking about, nor whether what we are saying is true.” This divorce between scientific knowledge and common experience marked a decisive break from the Enlightenment ideal that had dominated Western thought since the 18th century.
The new physics proved particularly challenging for public comprehension. While Einstein’s theories eventually became household names, their actual content remained mysterious to most educated laypeople. As one historian observed, the revolution was “accepted existentially rather than intellectually”—incorporated into technology and vocabulary without being fully understood at a conceptual level.
Legacy and Modern Relevance
The intellectual transformations of 1870-1914 established the framework for 20th century science and continue to shape our understanding of the world today. Quantum mechanics and relativity remain pillars of modern physics, while genetics forms the foundation of contemporary biology. The mathematical innovations of this period underpin everything from computer science to economic modeling.
Perhaps more significantly, these developments altered humanity’s relationship to knowledge itself. The realization that scientific theories could be simultaneously enormously powerful yet fundamentally counterintuitive or incomplete marked a profound shift in epistemological assumptions. As Thomas Kuhn would later argue in The Structure of Scientific Revolutions (1962), this period exemplified how scientific progress often occurs through paradigm shifts rather than gradual accumulation of facts.
The pre-World War I intellectual revolution also demonstrated how scientific advances interact with broader cultural and social changes. While specific discoveries might emerge from specialized research, their acceptance and interpretation inevitably reflect the historical context in which they occur. The crisis in classical physics mirrored wider uncertainties in a world undergoing rapid industrialization, imperial expansion, and social transformation.
Today, as we confront new scientific frontiers in quantum computing, genetic engineering, and artificial intelligence, we continue to grapple with questions first posed during this remarkable period of intellectual ferment. The late 19th century’s legacy reminds us that scientific progress often requires abandoning comfortable certainties in favor of more complex, if less intuitive, understandings of reality. As the physicist Max Planck observed, “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”