What so special about the number seven?

Colours in the rainbow, days in the week, dwarves, seas, continents, deadly sins, Japan’s Lucky Gods… Seven plays a huge part in our daily, global culture.

In Chinese culture, it represents the sum of the five elements (metal, wood, water, fire and earth), plus yin and yang, and hence in Confucianism represents harmony and in Taoism beauty and kindness. It symbolises togetherness and is a lucky number for relationships.

It runs as a red thread through the classics, from the wonders of the world to the Seven Sages, as this essay from 1858 shows.

In science, it seems that seven is the ideal unit for short-term memory (Miller’s Law), and the neurons of the brain work best if they have seven dendrites.

And in business, it’s a great number for an effective team.

In a recent poll, mathematician Alex Bellos found that it’s our favourite number, with one respondent explaining it as being ‘because it is a bit awkward; it can’t be equally divided and won’t bend to the rules so easily’. Perhaps that’s the best reason to love it I’ve heard.