Let There Be Light

The ultimate measure of progress

Oct 24, 2024

Risk & Progress| A hub for essays that explore risk, human progress, and your potential. My mission is to educate, inspire, and invest in concepts that promote a better future. Subscriptions are free, paid subscribers gain access to the full archive, including the Pathways of Progress and Realize essay series.

Light may be the ultimate testament to human ingenuity. By the year 1900, the Second Industrial Revolution was in full swing. Electricity generated via steam turbines, slithered into our homes, enabling households to take advantage of electrically powered devices for the first time. One of the primary drivers of electrification was the invention of the incandescent lightbulb. Lighting on demand, at the flick of a switch, changed everything. With the incandescent bulb, we could safely work and play in the dark of night without candles or oil lamps. The lightbulb made the production of light vastly more efficient and affordable.

There is perhaps no better example of the potential of progress than found in the history of illuminating the darkness. William Nordhaus, in a study on the subject, tracked the progress of lighting technology from pre-history to modernity, from the open fire to the lightbulb. One of our pre-historic ancestors, Homo erectus, tamed fire and used it for cooking and lighting at least 1 million years ago, but it was the inventiveness of our species, Homo sapiens, that advanced beyond. Some 40,000 years ago, we created the first simple animal-fat burning stone “lamps.” Progress from there was slow…until it wasn’t.

At about 0.015 lumens per watt (a measure of light per unit of energy), these stone oil lamps were roughly 7 times more efficient than an open fire (0.00235 lumens per watt). By the First Industrial Revolution, candles and oil lamps reached about 0.10 lumens per watt or roughly 7x the efficiency of those early stone “lamps.” The incandescent lightbulb, a product of the Second Industrial Revolution, was a massive leap forward, ~37x more efficient, producing an astonishing 3.7 lumens per watt. Yet, by the end of the 20th century, the efficiency of the incandescent lightbulb quadrupled to about 14.2 lumens per watt. After 2000, LED lighting, an invention of the Information Technology revolution, took this further, achieving about 100 lumens per watt, another 7x improvement.

The vast leaps in efficiency, our ability to produce more photons using less energy, have been so dramatic that I cannot properly represent them on a chart. As you can see below, the efficiency of anything before the lightbulb is so small that it doesn’t even register.

Even these dramatic leaps in efficiency pales in comparison to the cost compression of lighting. As we will see in our study of progress, humanity became wealthy in two ways. First, most obviously, by growing incomes, the size of our paychecks, but second and more importantly, by compressing the cost of goods and services by doing more with less. Here, the improvement in lighting efficiency allowed humanity to produce more light at an immensely lower cost.

Comparing the “cost” of lighting over this vast period is difficult because currency fluctuations and inflation make any representation in “dollars” or “cents” meaningless. Instead, we must turn to “time prices” (special thanks to

Gale Pooley

and HumanProgress.org) that is, looking at the amount of time the “median worker” had to labor to purchase a given amount of light. Our prehistoric ancestors, with their crude stone “lamps,” needed to “work” about 50 hours to “buy” 1,000 lumen-hours of light. In practice, this meant hunting and gathering animal fat, as there likely was no market from which to “purchase” anything. By 1800, due to rising incomes and the ~7x efficiency improvement of candles, the labor required to buy the same 1,000 lumen-hours was cut by almost 90%, to about 5.4 hours.

As the Industrial Revolution gave way to the Second Industrial Revolution and then the IT Revolution, incomes rose further and faster, efficiency improved and progress accelerated. By 1900, that 1000 lumen-hours could be purchased with about 13 minutes of labor, and by 2000 it required just a fraction of a second of human labor. Today, with the 7x improvement of LED lighting, the time-cost to buy 1000 lumen-hours is so small that it is hardly worth measuring. In the chart below, we see precisely the opposite of the above; the efficiency improvements over time render the cost of lighting almost imperceptible after the lightbulb's invention.

From Scarcity to Abundance

A candle at one’s bedside was once a mark of luxury. We have transformed something that was once scarce into something incredibly abundant. Lighting on demand is now so ubiquitous that it’s difficult to imagine life without it. Artificial light is so fundamental to progress and growth that it’s a valuable data point for economists. Using satellites positioned in the Earth’s shadow, we can observe, measure, and track the amount of light emitting from the cities and nations on the surface. This tells us a great deal about the growth occurring below, free from the manipulation of government statistics. Light, therefore, may be the ultimate measure of human progress. It is perhaps no coincidence that the symbolic representation of an idea, used in everything from emojis to movies, is a lightbulb.

You also may like…