It is just a number – 1.618 – but to its devotees the ratio expresses aesthetic perfection, and can be found wherever there is beauty.
For example, they argue that of all the rectangles in the world the most pleasing to the eye has a ratio of length to width of 1.618.
And of all the smiles in the world, they maintain that the most beautiful have their central incisors 1.618 wider than their lateral incisors, which are 1.618 wider than their canines, and so on down through the molars.
There are web pages devoted to where else on the human face you can find the golden ratio, which is also known as the golden section, golden proportion or golden mean.
Even though I am sceptical about many of these claims, it is undeniable that 1.618 can be found quite easily on the human form – even on ugly people.
For example, if you mark the tips of the knuckles on your finger with a pen, the distance between first and second knuckle is about 1.618 times the distance between the second and the third.