Essential Innovations

Northwestern economic historian Joel Mokyr shared his expertise for the Atlantic’s “The 50 Greatest Breakthroughs Since the Wheel.” Here are Mokyr’s selections for 10 of the most important technological advances in history.

Germ Theory of Infectious Disease

Before Pasteur and Koch discovered that bacteria caused diseases, medical science was essentially clueless about the causes of infectious disease (which killed the majority of people). Clinical treatment of these diseases was ludicrous, preventive measures usually ineffective and/or misguided. Medical science made very few serious advances before 1870 and those that took place were serendipitous advances with zero understanding of how and why they worked. With the recognition of bacteria and other microorganisms as causal factors, preventive medicine was refocused and made effective, and mortality rates began to fall.

Engines — Both External and Internal Combustion

Energy comes in two forms, heat and motion. They can be transformed into one another, but at a serious loss of efficiency and economic cost. The steam engine (1712) converted heat into kinetic energy using the trick of differences in atmospheric pressure. The internal combustion engines of the 1860s did the same, but better. Because heat energy in the form of hydrocarbons was stored in fossil fuels in vast reserves, it opened up the possibility of using millions of years of stored up solar energy and convert it into work. Modern economic growth would not have been maginable without this.

Modularity — Interchangeable Parts

Nothing has changed production and the operation of mechanical instruments and tools more than the high-precision tools that made interchangeability possible by producing parts at very “low tolerances” of error. More than anything else, this insight made mass production possible through large batches of identical parts to be assembled subsequently, and parts standardization made for easy and cheap repairs by replacing as opposed to fixing broken parts.

Optical Lenses

The first eyeglasses appeared in Europe around 1285, the skill of lens grinders adding innumerable hours of reading and fine craftsmanship to people who had the good fortune to live beyond age 50 at that time. Three centuries later, the idea of combining convex lenses into microscopes and telescopes revolutionized science and helped nail down the Copernican view of the universe and the understanding of living organisms.

Alphabetization

Knowledge, if it is to be used, has to be accessible. But how to order it so someone can find what she is looking for? Before automated search engines, alphabetization in dictionaries, encyclopedias, and indexes at the end of books made knowledge vastly more accessible. It also may have contributed to the advantage of societies that had phonetic (non-ideographic) letters (as was the case in the West), since the ordering of words is much more natural. Technological progress wholly depends on the accessibility of useful knowledge.

Steelmaking

For most of the Iron Age, the iron used was of very low quality and better qualities were prohibitively expensive. The best quality iron was steel, which was known but took months of blacksmith labor (and special skills) to make and was thus unaffordably expensive. In 1740 crucible steel was invented, but the age of steel did not really begin until the Bessemer process and open hearth in the 1860s brought the price down. Steel is so vastly superior as a material that it changed the construction of buildings, ships, machinery and almost everything that depended on metal.

Nitrogen Fixing

Nitrates were increasingly in short supply in the late 19th century and needed more and more for fertilizer and explosives. The atmosphere contains 78 percent nitrogen — but how to extract (“fix”) it? The problem had defeated some of the best chemists of the time, until German physical chemist Fritz Haber and his associates cracked the problem on the eve of World War I — just in time to permit Germany to make the explosives to fight for four years instead of four months. Ugly — but without it, the earth might not have been able to feed and sustain more than half of the current 7.1 billion people.

Paper

Reams have been written on the importance of the printing press, but few seem to have noticed that it would have been awfully hard to print books on clay tablets and parchment and that papyrus was unavailable to most of the world and did not last in wet climates. Invented — like so much else — in China and transferred to Europe via the Islamic world, paper turned out the ultimate storage device of information before magnetic disks.

Telegraph

Before the telegraph, with few exceptions, information could move no faster than a man on horseback. Smoke signals, homing pigeons and the semaphore telegraph all had very little bandwidth and were unreliable. The telegraph made it possible, at least in principle, for information to move at the speed of light and thus vastly improved long-distance communications and hence command and control over much larger territories. And no, it was not invented by a man named Samuel Morse, despite what 90 percent of Americans believe.

Jacquard Loom

What loom? Jacquard who? The 1804 machine built by a French engineer Joseph-Marie Jacquard to weave patterns in high-end textiles was the first technique to utilize digital technology using punch cards on which the pattern to be woven was designed (a bit like street organs). Napoleon loved it, so did Cambridge mathematician Charles Babbage, who realized the potential of binary coding and built the first calculating machine in the 1830s. Babbage had a picture of Jacquard hanging in his study, woven — quite appropriately — on a Jacquard loom. Digital technology has begun to revolutionize the world in the closing decades of 20th century, and the end is nowhere in sight. Digital society may be to analog society what the Iron Age was to the Bronze Age. Fasten your seatbelts.