For better seeing
Nor to peer from a window. Rather abide
At the center of your being;
For the more you leave it, the less you learn.
Search your heart and see
If he is wise who takes each turn:
The way to do is to be."
I was recently catching up on back episodes of the truly excellent British History Podcast (which I strongly recommend if you haven't yet discovered it), and found myself listening to an argument between a number of history podcasters over which person was the most influential in all of history.
An interesting question, and one virtually impossible to answer without a time machine, because you never know if somebody changed everything, or was simply marching in front of the parade. For example, you could argue that Constantine ushered in the age of Christianity, which had enormous influence over Europe and most of the rest of the world. On the other hand, Christianity was already spreading rapidly. If not Constantine, would some other Emperor a few decades later have done the exact same thing? Similar arguments can be made for many historical events and technological innovations.
However, there is one figure who I think is a very strong candidate for the most influential person of all time, by virtue of the fact that if he hadn't been exactly where he was, there's at least a reasonable chance that the entire human species would have come to a very abrupt end.
Stanislav Petrov was a Soviet officer monitoring a nuclear early warning system. On September 26, 1983, the alarm went off, indicating five missiles had been launched from the United States. Imagine yourself in his shoes. You have moments to decide, and only one chance to get it right. The fate of your entire nation, and the rest of the world, lies in the balance. Your worst enemy has done what everybody feared, and launched a pre-emptive strike. Under these circumstances, could you even think straight?
Commander Petrov clearly could. This attack made no sense to him. He knew that the United States knew that an attack would precipitate a counter-attack. The only hope for victory under this scenario was to wipe out your foe in one sudden onslaught. Five missiles wouldn't do that.
So Commander Petrov made an instant decision. With no time to run a diagnostic on the system, no theory to offer as to what might have gone wrong, and knowing what was at stake, he informed his commanders that it was a false alarm. Based largely on this information, Soviet command chose not to launch a retaliatory strike. Petrov was correct. Later analysis showed that a quirk of the weather had played havoc with the system, indicating missiles where none existed.
Another man in that position might have easily made a different decision. It's not a sure thing that humanity would have been wiped off the map had Petrov called in sick that day, but it's a very real possibility.
So next time you weigh the influence of Aristotle versus Caesar versus Pasteur versus Napoleon, remember that had it not been for one man, you might not have the luxury of thinking about it at all. Remember Stanislav Petrov.