7.8 20th-Century Culture: Physics, Psychology, and Art

Physics shatters certainty

Albert Einstein's theory of relativity overturned Newtonian assumptions of absolute space and time, showing that measurements depend on the observer's frame of reference. Combined with quantum mechanics (Planck, Heisenberg), which revealed uncertainty at the subatomic level, science suggested the universe was far less predictable and orderly than 19th-century thinkers had believed.

Freud and the irrational mind

Sigmund Freud pioneered psychoanalysis, arguing human behavior is driven by unconscious desires, especially the id, not rational choice. This challenged Enlightenment faith in reason and rationality, suggesting people are governed by hidden, often irrational drives — a view that deeply influenced literature, art, and social thought.

Art breaks from realism

Rejecting traditional representation, movements like Cubism (Picasso), Expressionism, Surrealism, and Dadaism experimented with abstraction, distorted forms, and dreamlike imagery. These styles reflected the era's anxiety, disillusionment (especially post-WWI), and the influence of Freudian ideas about the unconscious mind.

Key terms

Theory of Relativity

Einstein's theory showing space and time are relative to the observer, undermining fixed Newtonian physics.

Psychoanalysis

Freud's method/theory arguing unconscious drives (especially the id) shape human behavior more than reason.

Quantum mechanics

Physics theory (Planck, Heisenberg) revealing uncertainty and unpredictability at the subatomic level.

Cubism

Art movement (Picasso) depicting subjects as fragmented geometric forms from multiple perspectives.

Surrealism

Art movement using dreamlike, irrational imagery, influenced by Freud's ideas about the unconscious mind.

Try an AP-style question

Einstein's theory of relativity challenged…

1. Darwin's theory of evolution
2. Newton's absolute time and space
3. the germ theory of disease
4. Marx's theory of class conflict