Science in the 20th Century

Course Overview

Embark on a grand tour of the sciences with a distinguished professor. As the 19th century drew to a close, the age-old quest to understand the physical world appeared to be complete, except for a few minor details. In fact, Albert Michelson, the first American to win a Nobel Prize in the sciences, noted that, “It seems probable that most of the grand underlying principles have been firmly established.” And he was far from alone among his peers.

Scientists in 1900 had no inkling of the other mind-boggling developments that lay in wait: plate tectonics, genetic engineering, space probes, nanotechnology, big bang theory, electronic computers, nuclear weapons, artificial intelligence, and many other astounding products of the human mind. Indeed, by the end of the 20th century, nearly every 19th-century theory of natural and social phenomena would be overthrown or superseded.

This dynamic transformation has not been a matter of revolution, but of evolution, as you’ll learn in this fascinating 36-lecture exploration of scientific growth filled with ideas, anecdotes, and insights. You’ll see how 20th-century scientists have built on crucial 19th-century concepts such as energy, natural selection, atoms, fields, and waves to assemble a body of knowledge to stun even the most farsighted scientific thinkers of that not-too-distant past.

You’ll come away with a new appreciation of how scientific knowledge expands, as Professor Goldman addresses a tremendous range of scientific and technological topics, including science and society, physics, mathematics, psychology, cosmology, telecommunications, meteorology, and archaeology.

Course Structure

01: The Evolution of 20th-Century Science

Professor Steven L. Goldman introduces the scope of the course and discusses the key features of 19th-century science that led to the extraordinary creativity and innovation of science in the 20th century.
Duration: 32 min

02: Redefining Reality

The first of 10 lectures on the physical sciences covers Einstein’s special and general theories of relativity, which undermined 200 years of physics and launched a wholly unexpected revision in our conception of the universe.
Duration: 30 min

03: Quantum Theory Makes Its Appearance

A puzzling phenomenon called the “blackbody radiation problem” inspired a new theory of the atom that would ultimately redefine reality and rationality. Professor Goldman tells the story of the inception of this bold idea, called quantum theory.
Duration: 30 min

04: The Heroic “Old” Age of Quantum Theory

Picking up the story of quantum theory in the 1920s, this lecture covers its growth into a mature system called quantum mechanics through key contributions by Niels Bohr, Erwin Schrödinger, and Werner Heisenberg.
Duration: 30 min

05: A Newer Theory-QED

In the 1930s, quantum mechanics entered its “working” phase, called quantum electrodynamics (QED), with increasingly comprehensive—and often bizarre—explanations for the interactions of matter and energy.
Duration: 30 min

06: QED Meets Fission and Fusion

As physicists began sorting out the structure of the atomic nucleus, an awesome source of energy came to light that found application in nuclear weapons and the first plausible theory of how stars work.
Duration: 30 min

07: Learning by Smashing

In order to explore the inside of atoms, physicists invented “atom smashers” to break them apart. These developed from the original 5-inch-diameter cyclotron of the 1930s to today’s mighty particle accelerators that are measured in miles.
Duration: 30 min

08: What Good is QED?

QED was a fertile theory that not only guided the development of nuclear physics from 1930 to 1960 but also raised philosophical issues about the status of truth. QED also led to practical applications such as semiconductors, lasers, and superconductivity.
Duration: 30 min

09: The Newest Theory-Quantum Chromodynamics

By the 1960s, the number of “elementary” particles created by atom smashers was in the hundreds and the need for a unifying theory was pressing. “Quarks” came to the rescue in a theory called quantum chromodynamics, proposed by Murray Gell-Mann.
Duration: 30 min

10: Unifying Nature

The success of quark theory fueled the search for further unification, specifically in a theory that would unite the four fundamental forces of nature. That effort has spawned such strange ideas as loop theory and string theory, and involves picturing conditions at the instant of the Big Bang itself.
Duration: 30 min

11: Chemists Become Designers

The final lecture on the physical sciences traces the revolution in chemistry due largely to Linus Pauling’s quantum theory of the chemical bond in the 1930s, which together with the advent of supercomputers now makes it possible to create designer molecules.
Duration: 30 min

12: Mathematics and Truth

Professor Goldman pauses in his tour of 20th-century science to explore the curious power of mathematics to explain nature. How can mathematical abstractions tell us anything about concrete experience?
Duration: 30 min

13: Mathematics and Reality

Continuing his discussion of mathematics, Professor Goldman shows that 20th-century developments in mathematics were every bit as breathtaking as developments in the theories of matter, energy, life, Earth, and the universe.
Duration: 30 min

14: The Universe Expands

The first of three lectures on the universe charts our evolving conception of the universe, from 1900 when the Milky Way was thought to be the only galaxy there was, to the discovery of an expanding universe of countless galaxies in the 1920s and the formulation of the Big Bang theory in the late 1940s.
Duration: 30 min

15: What is the Universe?

Bolstered by the discovery of the cosmic background radiation in the 1960s, the Big Bang theory underwent a startling modification in the 1980s called inflation theory that radically enlarged the estimated size of the universe. Recent observations also show that the universe’s expansion is accelerating, contrary to all expectations.
Duration: 30 min

16: How Do We Know What’s Out There?

This lecture spotlights the fascinating variety of instruments that have unveiled the universe in the course of the 20th century, from ground-based optical, radio, and neutrino telescopes to spacecraft that are surveying the cosmos at x-ray, gamma ray, infrared, and other wavelengths.
Duration: 30 min

17: From Equilibrium to Dynamism

The first of three lectures on earth sciences contrasts the picture of a stable Earth that prevailed in 1900 with the dynamic planet that emerged from the theory of plate tectonics in the 1960s, which was inspired by Alfred Wegener’s rejected theory of continental drift from 1915.
Duration: 30 min

18: Subterranean Fury

Plate tectonics was a “Copernican revolution” in our conception of Earth, which not only explained features that had long baffled geologists, but led to new insights about Earth as a complex system of relationships among the constantly changing atmosphere, oceans, core, mantle, and crust.
Duration: 30 min

19: Solar System Citizen

This lecture considers our planet’s place in the solar system and examines one of the most outstanding accomplishments of the 20th century: the exploration of Earth, the Moon, and planets by spacecraft.
Duration: 30 min

20: Science Organized, Adopted, Co-opted

Professor Goldman begins a pair of lectures examining science from the “outside” by tracing the origin of the public commitment to big science in the U.S. From limited government support in the 19th century, science grew to an endeavor that consumed an estimated $1 trillion of public funds in the second half of the 20th century.
Duration: 30 min

21: Techno-Science and Globalization

One of the most important of all scientific developments in the 20th century was the new relationship between science and society, with science increasingly being equated by the public with truth. At the same time, the scope and direction of scientific research was becoming increasingly subject to political influence.
Duration: 30 min

22: The Evolution of Evolution

The first of five lectures on life sciences shows how Charles Darwin’s version of evolution was rescued in the early 20th century by the discovery of radioactivity, which led to proof that Earth was billions of years old, and by the rediscovery of Gregor Mendel’s forgotten 1865 paper on inheritance in plants.
Duration: 31 min

23: Human Evolution

Spectacular fossil finds in the 20th century provide a detailed picture of the evolution of our species. Recently, this picture has been greatly enhanced by a powerful new technique that uses DNA to trace prehistoric human migration.
Duration: 30 min

24: Genetics-From Mendel to Molecules

Between 1900 and 1910, genetics emerged as the dominant theory of inheritance, sparking a quest to understand the nature of the gene and ultimately leading to the identification of DNA (originally considered “uninteresting”) as the carrier of the genetic code.
Duration: 30 min

25: Molecular Biology

The once-controversial idea that life can be explained by chemical phenomena triumphed in the 20th century with the astonishing success of molecular biology in unraveling the basic structures of living systems.
Duration: 31 min

26: Molecular Medicine

Concluding the series on the life sciences, this lecture looks at the application of discoveries in microbiology and other physical sciences to medicine, highlighting advances in pharmaceuticals and medical imaging.
Duration: 30 min

27: Culture-Anthropology and Archaeology

Beginning an eight-lecture series on the social sciences, Professor Goldman traces the development of different schools of anthropology and the shift in archaeology from collecting artifacts to explaining cultural development through material remains.
Duration: 30 min

28: Culture-History

Is history a science? This lecture follows the shifting fortunes of objectivity and relativism as historical methodologies. The latter culminated in the extreme form of relativism known as post-modernism, which attacked the foundations of science itself.
Duration: 30 min

29: Culture-Linguistics

Linguistics underwent a profound change in the 20th century, with the focus shifting from the historical study of languages to theories of how language works, developed by Ferdinand de Saussure, Edward Sapir, Benjamin Lee Whorf, Noam Chomsky, and others.
Duration: 31 min

30: Society-Sociology

What is a society? What distinguishes it, what keeps it together over time, and what are the laws of its functionality? 20th-century sociology moved from grand theories of society to the detailed study of social processes and institutions.
Duration: 30 min

31: Society-Political Science

In exploring the relationships of power and authority that underpin society, Professor Goldman focuses on theories of what holds the fragmented, pluralistic American democracy together.
Duration: 30 min

32: Society-Economics

In 1900, “the economy” did not exist as a concept, but as the 20th century unfolded, a new breed of intellectuals called economists strove to explain and influence the intricate forces of supply, demand, production, distribution, and consumption.
Duration: 31 min

33: Mind-Classical and Behavioral Psychology

The quest to understand human psychology spawned startlingly different approaches in the 20th century, including the theories of Sigmund Freud and Carl Jung, Gestalt psychology, and the behaviorism of B. F. Skinner. Since the 1970s, the mind-centered approach of cognitive psychology has dominated.
Duration: 31 min

34: Mind-Cybernetics, AI, Connectionism

The final lecture on the social sciences examines the rapid progress since the 1940s in using computers to model the operation of the mind—an effort called artificial intelligence that raises the formidable question: What is mind?
Duration: 30 min

35: Looking Back

Professor Goldman looks back on the previous 34 lectures, drawing provocative conclusions and asking probing questions, such as: Does the increasing explanatory and predictive power of science mean that science is drawing closer to the truth?
Duration: 30 min

36: Looking Around and Looking Ahead

Where are the sciences headed? The forecasts of 19th-century thinkers about the 20th century could not have been more wrong, but Professor Goldman hazards a few informed and fascinating predictions about the 21st century.
Duration: 31 min