Fears of numbers are an absurd but very real psychological phenomenon, and a fascinating one to try and explain.
Car manufacturers may avoid a particular number in a vehicle name. Town planners may avoid a certain number in avenue naming. People avoid living in a certain house number. Teams or drivers may avoid a certain competition number, and motorsport commentators may fixate on a particular digit relating it to luck. And (in normal times when they're allowed to) hordes of people may avoid going out on a particular day.
But it's all been made up, and arbitrarily so. Here are just three of the reasons why.
1 - They're merely an old rumour
The first thing proving they're made up is you'll be more fearful of a particular number depending on your cultural background, so the fear is taught. For example, many Asians fear four (Tetraphobia), whereas some westerners fear 13 (Triskaidekaphobia).
Politicians and advertisers know that if you repeat something often enough and for long enough, people begin to believe that it's true, even if there's no valid evidence to support it. This constant repetition right from early childhood is the only explanation as to why anyone fears 13, or any Friday the 13th.
There are some interesting theories as to why the fear of 13 and Friday the 13th came about, but there's no consensus as to its origin, and the superstition persists even without any reasonable explanation.
One could point to ancient Babylonian laws that skipped the 13th one, but others point out they weren't numbered and say a line was missed due to clerical error, so the reality is we're just scratching around for reasons, not examining a real pattern.
Whatever the origin, it's had a lasting impact. Each Friday 13th has a noticeable effect on various economies because people are less willing to go out, and less willing to make any significant purchase like a vehicle or house, and less willing to do a significant business deal. Put simply, less money will change hands that day.
As for the number four, there is at least the explanation of word association. You see, the sound of the word four in Japan, China, Vietnam and Korea is phonetically similar to each of their words for death.
However words are just made up sounds to communicate with, and the sounds used in one language can mean something completely different in another. One particularly immature but amusing example of this is the sound of the word Pajero actually means wanker in Spanish. That one is unfortunate, but it's not the same as naming your vehicle the CX death in your native language which is why there's no CX4 (it's a CX30 instead).
2 - Numbers are an invention
Some languages don't have numbers at all, and different numerical systems have been invented for counting. The ancient Sumerian system was base 12 (which has some different prime numbers to base 10), and some theories around the fear of 13 are from the base 12 system, but the system we're taught now is base 10 (decimal). So what number should you fear now? 11? Other examples are computers often use a base of 8, 16, 32 or 64 because they're compatible with binary (1s and 0s), ancient Mayans were known to use base 20, and Babylonians used sets of 60.
3 - Days are also made up
The seven day week traces its roots back to the Sumerian calendar of 21st century BC, and it sort of breaks up the lunar phases into four segments. The Sumerians also had a 12-month calendar based on the moon, but they needed to add an extra month every few years to keep in line with the seasons. The Babylonians centuries later instead chose to insert one or two days into the final week of each month because the moon cycle is about 29.53 days long.
Other systems existed too. The current Chinese year is 4719, and centuries ago they had 10-day weeks. The Egyptians had a 10-day week too, but the Romans had an eight-day week until they eventually adopted seven.
The start of a year has changed too. The western switch from the Julian to Gregorian calendar from the late 16th century meant skipping 10 days (more if done later), and prior to that the initial Julian year was 445 days long to realign it. So what day is it really?
