In my article accompanying our "50 Greatest Inventions [since the wheel]" project last month, I said that since such a list was inevitably arbitrary, its real value would be the discussion it provoked about what else could have been considered and why.
Herewith, a small sample of the "well, what about ....?" correspondence that continues to flow in. First, from a reader in Indonesia who offers a list of 50 social breakthroughs that, in his view, made the 50 tech breakthroughs possible. A few of these overlap with our list, but many are new:
50 Social innovations that changed the world more or less in chronological order. Rank order in top 10 shown in [ ]
1. Irrigation that
2. created a structured bureaucracy, land measurement and administration in Egypt and Mesopotamia
3. mathematics 
4. creation of nations as workable structures
5. empires based on bureaucracy and military discipline
6. writing, instructions could be sent over distance – Incas used knots 
7. written rules and laws - the lawyers and courts as independent
8. alphabet 
9. agriculture and and animal husbandry skills that could be recorder and spread
10. history as peoples myths and lessons
11. democracy in Athens -
12. rhetoric - philosophy – applied mathematics
13. 0 zero 
14. Universities, scientific societies, 
15. religious orders, The church built on Roman Model
16. The Holy Roman Empire
17. currency and letters of credit  money
18. double entry bookkeeping
19. money and banking by goldsmiths in Amsterdam, Florence
20. paper money in France
21. Treaty of Westphalia (1648) nation state
22. Joint Stock company (mutual fund) to spread risk of merchant adventurers
24. the stock market
25. corporations 
26. copy rights, patents,
27. colonial administration - East Indies Company
28. federalism - US constitution
29. income taxes 
30. payroll deductions
31. social security
32. civil service as in Germany 
33. public schools Land grant colleges
34. scientific agriculture 
35. science in medicine 
36. public health by Florence Nightingale and JS Mills 
37. international press - media (WWI) and propaganda
38. research organizations such as bell labs, Medlo Park
39. The League of Nations and UN
40. international organizations such as the postal union, maritime, trade, standards
41. United Nations (UN), Organisation for Economic Co-operation and Development (OECD) Organization for Security and Co-operation in Europe (OSCE), Council of Europe (CoE), 
42. European Union (EU; which is a prime example of a supranational organization), and World Trade Organization (WTO).
43. NGO Red Cross, YMCA, boy scouts
44. social media facebook G+
46. sports clubs and leagues
47. open society rational secular practical
48. records census, birth and death - statistical vital information
50. political science
In my article I said that one of our experts, Padmasree Warrior of Cisco, had suggested "the concept of the number zero" for our list. Many readers have written in to say that numbers, per se, should be added:
I found the list of greatest inventions and the story that accompanied it very interesting. I kept waiting for the printing press to appear and then I found it - number one on the list. While your story mentions the mathematics of calculus, I wonder if the concept of "number" was ever mentioned by the panel of experts? Was it considered and rejected for some reason, or was it not at all mentioned? I think "number" and concept of "numbers" is so ingrained in modern society it is easy to forget it was a human creation. It created a way to differentiate between "some" and "any".
Without the concept of "number" or "numbers" mathematics wouldn't exist. Base two mathematics is the framework on which the computer is based. I would consider the concept of "number" right up there with alphabetization (number 25 on the list). Clearly without written language or the concept of "number" the printing press would be of little use. What would one print?
There is a great book on the concept of "number", simply titled "Number", written by Tobias Dantzig in 1930.. Dantzig was born in Latvia in 1884 and moved to the United States in 1910, taking a job as a lumberjack in Oregon. He received a Ph.D. in mathematics from Indiana University in 1916 and taught at Johns Hopkins, Columbia University and the University of Maryland. He died in 1956 and sounds like an interesting character. I mean, how does one transition from being a lumberjack to getting a Ph.D. in mathematics?
And finally for now, one of the many people stumping for an equestrian breakthrough:
In addition to the thousands of other additions being proposed to your list of historic innovations, consider:
The saddle stirrup, which made armored knights and then cavalry possible. Before the stirrup, horsemen were archers, incapable of staying in the saddle after the shock of impact. Enormously significant in the wars of the last several hundred years.
Fertilizer, first natural then artificial. Without it, agriculture couldn’t be productive enough to support the population of the last millennium, never mind the next one. [We got at the artificial side of this, via #11 of our top 50, nitrogen fixation.]
Finally, the barometer. Until the invention of the barometer (and the understanding of the natural world it reflected) weather wasn’t predictable… indeed, predictability wasn’t even thought of.
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