Benjamin Todd

Since then, this astonishingly simple treatment has been used all over the world and the annual rate of child deaths from diarrhea has plummeted from around 5 million to 1.5 million.

Researchers estimate that the therapy has saved over 50 million lives to date, mostly children's.

If Dr. Nyland had not been around, somebody else would, no doubt, have discovered this treatment eventually.

However, even if we imagine that he sped up the rollout of the treatment by only five months, his work alone would have saved about 500,000 lives.

This is a very approximate estimate, but it makes his impact more than 100,000 times greater than that of an ordinary doctor.

But even just within medical research, Dr. Nyland is far from the most extreme example of a high-impact career.

For example, one estimate puts Karl Landstein as discovery of blood groups as saving tens of millions of lives by enabling transfusions.

Beyond the medical field, later in the guide we'll cover the stories of a hugely impactful mathematician, Alan Turing, and bureaucrat Viktor Zhdanov.

Or let's think even more broadly.

Roger Bacon and Galileo pioneered the scientific method, without which none of the discoveries we discovered above would have been possible, along with other major technological breakthroughs like the Industrial Revolution.

These individuals were able to do vastly more good than even outstanding medical practitioners.

Or consider the story of Stanislav Petrov, a lieutenant colonel in the Soviet army during the Cold War.

In 1983, Petrov was on duty in a Soviet missile base when early warning systems apparently detected an incoming missile strike from the United States.

Protocol dictated that the Soviets order a return strike.

Petrov didn't push the button.

He reasoned that the number of missiles was too small to warrant a counterattack, thereby disobeying protocol.

If he had ordered a strike, there's at least a reasonable chance hundreds of millions would have died.

The two countries may have even ended up engaged in an all-out nuclear war leading to billions of deaths and potentially the end of civilization.

If we're being conservative, we might quantify his impact by saying he saved a billion lives.

But that's almost certainly an underestimate, because a nuclear war would also have devastated scientific, artistic, economic, and all other forms of progress, leading to a huge loss of life and well-being over the long run.