The history of light (classic)

Overview

Using the history of artificial light, this episode explains how productivity growth can make society richer. It follows lighting from labor-intensive animal-fat candles and ancient oil lamps to kerosene, electric power, and highly efficient LEDs.

Economist Bill Nordhaus compared lighting technologies by asking how much light a person could buy with one day’s wages. In ancient Babylon, that labor purchased roughly ten minutes of modern-equivalent light; by the 1990s, it purchased about 20,000 hours.

The episode argues that progress depends on more than isolated inventions. Scientific institutions, patents, corporations, banks, investors, and infrastructure helped turn discoveries into affordable services used at scale. It also acknowledges that growth brings pollution and other environmental costs.

Segmented Summary

[00:23] Bill Nordhaus and the Possibility of Shared Gains

[Fact] Host Jacob Goldstein introduces the episode as a tribute to economist Bill Nordhaus, who died at age 85.

[Fact] Nordhaus later received the economics Nobel for his work on the economics of climate change.

[Fact] Goldstein identifies the episode’s central economic lesson: the “pie” can grow, making it theoretically possible for everyone to become better off.

[01:17] Making Light from Animal Fat

[Fact] Before electric lighting, people commonly produced light by burning fat with a wick.

[Fact] Goldstein buys beef fat, melts and strains it, then repeatedly dips twine into it to make six small candles.

[Fact] The experiment takes hours even without counting the labor required to raise the cow, obtain the fat, or manufacture the twine.

[Fact] The hosts use this process to introduce a broader question: how humanity moved from costly, dim candles to abundant light available at the flip of a switch.

[04:47] The Historical Difficulty of Producing Light

[Fact] Lighting historian Jane Brox evaluates the homemade candles and confirms that they work, despite their poor appearance.

[Fact] Different societies used locally available sources of energy, including dried salmon, fireflies, and oily storm petrels.

[Fact] These methods required substantial labor, and Harriet Beecher Stowe described making animal-fat candles as seven times worse than washing clothes.

[Fact] The cost and inconvenience of early lighting reflected low productivity throughout the wider economy.

[07:37] Nordhaus’s Method for Measuring Progress

[Fact] Nordhaus sought to calculate how the cost of light changed over thousands of years.

[Fact] He found Babylonian wage and price data dating back about 4,000 years.

[Fact] To measure the output of ancient lighting, he burned a reproduction lamp in his dining room and measured its brightness with a borrowed light meter.

[Fact] His comparison asked how long a day’s wages could illuminate a small room at approximately the brightness of a modern bulb.

[09:37] Ten Minutes of Light for a Day’s Labor

[Fact] In ancient Babylon, an entire day’s wages purchased the equivalent of roughly ten minutes of modern-bulb light.

[Fact] Food production, animal raising, and candle making were all difficult and labor-intensive.

[Fact] Darkness was restrictive and dangerous rather than merely atmospheric; the episode cites a historical Parisian law requiring residents to surrender their keys and remain locked indoors at night.

[Fact] For thousands of years, most people worked primarily to obtain enough food, while both lighting technology and the wider economy improved only slowly.

[10:53] Productivity as the Engine of Growth

[Fact] The episode defines economic improvement as finding ways to accomplish tasks with less labor.

[Fact] Roman lamp designs and whale oil produced incremental advances, but lighting still depended on burning naturally available materials.

[Fact] Even by the 1700s, most people remained subsistence farmers, and transportation still relied on walking, horses, and sailing ships.

[Fact] Nordhaus says the gains between ancient Babylon and approximately 1800 were modest compared with what followed.

[12:07] Kerosene and the Acceleration of Innovation

[Fact] Around 1800, the pace of improvement in lighting began to accelerate dramatically.

[Fact] Kerosene, developed around the mid-19th century from coal or oil, was brighter, cleaner, and cheaper than earlier fuels.

[Fact] A day’s wages purchased about one hour of whale-oil light but approximately five hours of kerosene light.

[Fact] The rise of professional science and university-based experimentation helped create conditions for breakthroughs such as kerosene.

[Fact] Cheaper lighting supported streetlights and enabled more people to go out after dark.

[14:10] Why the Light Bulb Needed Capital

[Fact] The invention of a durable electric bulb was not sufficient by itself to deliver cheap electric light.

[Fact] Thomas Edison needed substantial financing to build generating infrastructure and distribute electricity.

[Fact] J.P. Morgan and other investors financed the power station that made Edison’s lighting system commercially viable.

[15:37] Building the First Central Power Station

[Fact] Edison’s Lower Manhattan power station was completed in 1882 and is described as the world’s first central power station.

[Fact] On September 4, 1882, Edison activated the system from J.P. Morgan’s office.

[Fact] Electric lights came on across roughly one square mile of Lower Manhattan.

[Fact] Edison continually compared his system’s costs with those of incumbent gas lighting, treating economic viability as part of the invention.

[17:50] The Institutional Structure Behind Innovation

[Fact] The episode argues that the surrounding economic structure contributes more to growth than isolated “eureka” moments.

[Fact] Edison depended on patents to protect ideas, corporations to pool investment, banks to provide capital, and infrastructure to distribute electricity.

[Fact] These institutions allowed multiple investors to risk large sums on power plants and wiring for an unproven system.

[Inference] The episode presents successful innovation as a coordinated social and financial process rather than the achievement of a lone inventor.

[18:34] Growth’s Environmental Costs

[Fact] Early electric power plants burned coal and produced significant pollution.

[Fact] Edison’s company reportedly stopped feeding coal into one Manhattan plant whenever Health Department photographers appeared.

[Fact] The episode contrasts these environmental costs with the widespread benefits of inexpensive electric lighting.

[Inference] Its account treats growth as valuable but not cost-free, suggesting that productivity gains should be evaluated alongside their external consequences.

[18:59] From Scarcity to Abundance

[Fact] New technologies such as the internal-combustion engine and tractor helped make it possible for most people to work outside agriculture.

[Fact] In ancient Babylon, one day’s labor purchased about ten minutes of light; with 19th-century kerosene, it purchased about five hours.

[Fact] By the 1990s, Nordhaus estimated that one day’s labor could purchase roughly 20,000 hours of light.

[Fact] This rise in productivity allowed people to work less or spend their income on goods and experiences that had once been limited to the wealthy.

[20:44] LEDs and Continuous Incremental Improvement

[Fact] LED manufacturer John Edmond describes experiments that extract more light through changes in materials or chip design.

[Fact] The episode connects annual economic growth to countless small improvements that make products better, faster, or less expensive.

[Fact] This cumulative process has continued across many sectors for hundreds of years.

[21:25] Can Productivity Growth Continue Forever?

[Fact] The hosts ask whether continuing economic growth will eventually exhaust the available ways to improve products.

[Fact] Edmond says physical limits prevent technologies from improving without bound.

[Fact] He suggests that lighting efficiency may be approaching such a limit, although some further improvement remains possible.

[Inference] The broader growth story may therefore depend on discovering new fields of innovation rather than endlessly optimizing mature technologies.

Podcast Commentary/Summary

The episode’s main strength is its use of light as a concrete measure of economic progress. Converting prices into hours of labor makes the difference between ancient scarcity and modern abundance unusually vivid.

It also offers a valuable corrective to simplified stories about heroic inventors. Edison’s achievement depended on science, finance, patents, corporate organization, and physical infrastructure, showing how institutions transform inventions into widely available services.

The discussion acknowledges pollution and environmental damage but explores those costs less deeply than the benefits of growth. [Inference] Listeners seeking a fuller account of inequality, resource depletion, or who benefits from productivity gains may find the treatment incomplete.

[Inference] The episode is especially suitable for listeners interested in economics, technology, business history, and the relationship between productivity and living standards.