Why are 17th and 13th bad luck? The origins and spread of superstitions about numbers

The idea that certain numbers bring bad luck is widespread throughout the world. The numbers considered bearers of misfortune, however, they are not the same everywhere: in Italy the “unfortunate” number is 17, in most of Europe and America it is 13, in the Far East it is 4.

The origins of superstitions about the 17th and 13th they are not clear and to explain them various theories have been put forward, mainly linked to mathematics or religion. However, the fear of 4 is easily explainable.

Of course, phobias about “unlucky” numbers, like all superstitions, are completely irrational and devoid of any scientific basis.

The fear of 17 in Italy

In Italy, the unlucky number par excellence is 17. The superstition has a specific name, heptacaidecaphobiathat is, fear of the 17th (from heptacaideca And phobia), and has many “applications”. For example, according to the Neapolitan grimace 17 is the number that must be played in the lottery if misfortune happens or dreams; sometimes, in the numbering of seats on means of transport, row 18 is directly after row 16. The worst case occurs when the the 17th day of a month falls on Fridaywhich in itself is already considered unfortunate because it is the day of Jesus’ death (Good Friday).

Alitalia plane without row 17

There is no univocal explanation regarding the origins of heptacaidecaphobia. It seems that the 17th was already abhorred Pythagoras and by his followers in the 6th century BC. C., because it is found in the middle of two “perfect” numbers, 16 and 18, which represent two quadrilaterals (4×4 and 6×3). The phobia was also widespread in ancient Rome and probably arose from the fact that 17 was written xviiwhich is the anagram of vixi, that is, “I lived” (in the sense of “I no longer live, I died”).

What is certain is that since the time of ancient Rome the phobia of 17 it never disappearedbut it is widespread only in Italy.

Superstitions about the number 13

In much of the world the unlucky number is 13. The superstition, which takes the name of triscaidecaphobia, is widespread in almost all Europe, in the United Statesin Latin America and in some other countries.

A racetrack in California.  Stall 12A replaces stall 13

Again, several explanations are possible. First of all, 13 is the number that comes after 12, a highly composite figure (it is divisible by 2, 3, 4 and 6). If a thirteenth element is added to 12, any subdivision is made impossible, because 13 is a Prime number (i.e. it is divisible only by one and itself). In essence, the thirteenth element can create disorder in an ordered whole.

However, they also exist explanations related to religion. For Christianity,Last Supper 13 guests participated: Jesus and the twelve apostles. This gives rise to the phobia of having 13 people at the table. Even in the Norse mythology there is a negative reference to the number 13: it is said that the god Loki, not invited to a dinner attended by twelve divinities, showed up anyway, as the thirteenth guest, and caused the death of one of the guests. The thesis according to which phobia derives fromarrest of the Knights Templarwhich occurred on 13 October 1307, but it is an unfounded assumption, because Triscaidecaphobia already existed previously.

Not all over the world, after all, 13 brings bad luck. There are places, such as Tibet, where the number is considered favorable. In Italyhowever, the attitude is ambiguous: in some cases, such as at the table, 13 is considered “dangerous”, but on other occasions it has a favorable meaning: “make thirteen” it is synonymous with having a big stroke of luck, because in the game of football pools it is the highest possible score and guarantees huge cash prizes (consider that until the 1990s the football pools was much more popular than today).

The phobia of 4 in the Far East

Phobia of the number 4, or tetraphobia, is widespread in Far East, particularly in China, Japan, Korea and Taiwan. In this case the origin is clear: in Chinese the number 4 is called Yes (according to the most widespread transliteration of the Chinese language) and the sound is very similar to the word “death”(Yes). The same assonance is present in Japanese and Korean.

Shanghai elevator.  The 4, its compounds and the 13 are missing

Accordingly, Eastern peoples believe that the 4 and its compounds (14, 24, 40, 41, etc.) bring bad luck. In many cases, in the numbering of the floors of buildings we go directly from the third to the fifth floor and in Hong Kong there are even skyscrapers which skip, in addition to the 4, all the numbers from 40 to 49: after the 39th floor, there is the 50.