Is the world ending anytime soon? Judging from the news, all does not look well going forward. Do you know the feeling?
To get a sense of the likelihood of imminent demise, let’s start with a couch. Yes, a couch — as unlikely as that may seem.
Suppose you want to measure the length of your couch. You grab a tape measure and discover the couch is 60 inches long. But is it?
You assumed the tape measure was accurate. You also assumed that your tape was straight when you strung it along the length of the back of your couch, but what if you measured the front of the couch or arm to arm? In fact, you discover there are one hundred ways to measure the length of your couch and being a particularly precise and, dare I say, strange individual, you decide to religiously record each of those 100 measurements.
Having done that, you observe that some of the measurements are the same, but many are slightly different. So, what is the length of the couch, you ask?
Again, being a precise person, you add all the measurements and divide by the number of them to get the average and calculate that the couch is 60.1 inches long plus or minus 0.4 inches. Sounds good, but what does that mean? It means you have a rough idea within a certain margin of error. Welcome to the science of experimentation and measurement called Metrology.
You decide to plot all the measurements on a graph with the bottom axis marked off in increments of 0.1 inches, showing 59.7 inches at one end and 60.5 inches at the other. On the vertical axis, you plot the number of measurements of that particular value. The graph you make looks like a mound, with most observations falling between 59.9 and 60.3 inches.
So far so good. Now here is a key point. Your initial single observation of 60 inches was not wholly accurate, but not too far off either. In fact, any single measurement chosen at random of the 100 you made will likely be close to your average. You calculate next that a single observation has a 90% probability that it will lie between 59.8 and 60.2. You know this because you observed and counted it. Brilliant!
So, what does all this have to do with life ending tomorrow? Well, I’ll tell you.
The US is 244 years old. (This concept works for any country by the way, provided you know how long it’s been around.) Taking today as a random measurement like you did with the couch, you are likely observing the US from the middle of its lifespan, estimated at 488 years. If this is true, you can conclude that the likelihood of life ending next week, next month, or even next year, is quite small. The likelihood of the end coming in five years given your single observation and a prior 244-year history is only 2%.
So, cheer up!
No more long faces! There. That’s better.
Who knew that all that stuff we learned in school actually had a use?