More than 600 years ago William of Ockham is credited with inventing lex parsimonae, the law of parsimony. We know it as Ockham’s razor, the principle that where there are several hypotheses that predict equally well, the one with the fewest assumptions should be selected.

It serves as a useful rule because fewer assumptions mean less complex solutions and these are often preferable even when they make less reliable predictions.

You will also know the modern variant KISS — keep it simple stupid — that is wielded to stop us from wandering off to the never never lands of technical, logical and, dare I say, emotional complexity that so many of us find appealing.

I often wonder what William of Ockham who lived the life of a Franciscan friar in a time when witches were burnt and the life expectancy was closer to 30 than 50 would make of mobile phone neck.

What hypothesis might he have put forward to explain the epidemic of downward eyes and squashed chins? Prayer perhaps, certainly a simple explanation with few assumptions and a good fit to the behaviours of his day.

Collective deference would be an option, a mass display of respect to an unseen deity or perhaps in anticipation of a papal visit.

A sudden collective and consuming sadness from the realization that life was indeed hard and without hope of ripe old age.

It is impossible that he would have chosen the hypothesis that people are staring at a device that invisibly connects them to candy crush and tweets with such a force that they can no longer see the sky.

Clearly the razor must have context.

It works for the assumption set that is available at the time. In other words it is dependent on what is known. Friar Ockham had no idea that everyone would carry a mobile device or that they would be addicted to it to the exclusion of all others.

It remains true that the simplest explanation is usually correct. What is good to remember is that the truth, however simple, may not yet be known.