What Is Random?

What is random chance? What does it really mean that a dice has 6 perfectly equal sides, or that you have a 66.66% chance, or that a dice encountered interference?

Randomness pervades our lives. Things happen on a daily basis that we cannot explain, and thus we attribute the event to being “random”. Like what time does the bus arrive at the bus-stop when you go to school? You know that it’ll come around a certain time, but it’s rarely exactly on time – often being a little early, or a little late.

We would call the exact time that it arrives at a completely random event – because we have no influence over it.

However, that’s not exactly true. The time the bus arrives at ISN’T random at all, in fact. The time it arrives at is completely predicated by the events leading up to the exact time it picks you up. The bus driver woke up and left for work early, but then encountered heavy traffic. The first two bus stops were emptier than usual, but the next two were a bit more packed. He stopped for a quick coffee later, but then went a bit faster than normal to make up the time.

You could argue that the different circumstances leading up to each event were random, but they aren’t either. All have a basis in the actions of people. Someone decided not to go to work and take a holiday, another person took a later bus, road-construction slowed down traffic, etc.

The roll of a die too is a perceived, but false, random event. The way you cup your hand, the force put behind the throw, the smoothness of the table, the Rhino the die bounces from. If you had a strong enough computer, and accurate enough cameras to record the exact conditions immediately after the throw, before the die has touched anything, you could predict and determine how (and where) the die will land. It’s simple physics really.

For this reason, many physicists and mathematicians have been trying to discover something truly random – and its hard work! If anything, it’s so hard because Physics as we know it implies cause and effect. One event leads to another. If I drop a ball, I KNOW it will fall downwards. In the same way, even at especially small scales, where more and more apparently truly random events are occurring, we still can say with certainty that if one thing happens, so will something else.

A great example of this is the decay of a single atom. Normally decay rates are very easy to predict. An object will lose a certain % of its mass to decay in a given amount of time. For example, Radium has a half-life of 1602 years, meaning that in one thousand, six hundred and two years it will lose half of its mass (decaying into Radon gas). At masses of trillions of trillions of atoms of radium, this exercise is very predictable – so predictable that you can ascertain how old the radium is if you know how much there was at the beginning and how much there is now.

However, individual decay rates are a % chance that a single atom will decay at any given moment. Just like the school bus, you know roughly when it will, but not exactly when – sometimes it’ll be early, and sometimes it’ll be late. However, when you repeat the process a hundred thousand million times, you arrive at an average that will likely apply VERY CLOSE to the next hundred thousand million times. But it is still POSSIBLE that the entire bar of radium could go poof all at the same instant, or that it practically never decays.

The decay of a single radon atom is like that kind of situation. It could decay at any moment, and in truth you really can’t predict when. It could be one of the atoms that decays today, or it could be one that won’t decay for another 50,000 years. You can only give a percent chance that the particle will decay within a given time.

And even this, like the school bus, is not really random. As electrons and neutrons and preons and muons all fly around subatomic space, they’ll be hitting each other. At a large enough level it seems to be random, but it isn’t.

At the end of the day, true randomness is impossible, and all we can function on is perceived randomness. The less you can control the outcome of a die roll, the more random it is. So the next time your die rolls off the table, let it finish rolling – it’s actually more random now since you didn’t anticipate it going off the edge.