Couper les cheveux en quatre

The French expression couper les cheveux en quatre (literally "to cut a hair into four") is similar to the English expression to split hairs.  It means to excessively focus on tiny, insignificant details or to make overly fine distinctions, often to the point of being pedantic or unnecessary. It’s used to describe someone who complicates simple matters by overthinking or nitpicking.  

One might wonder: Why would the French go to the trouble of splitting a hair into four pieces, while the English are perfectly content with just splitting it?

Origin of the Expression:

The French expression dates back to the 16th century, a period when intellectual debates and philosophical discussions were highly prized in French culture. The idea of cutting a hair into four parts likely served as a metaphor for the kind of overly meticulous arguments that philosophers or scholars might engage in - a subtle nod to the intellectual culture of the time.

The French language has a penchant for creating vivid, sometimes bizarre, imagery to convey meaning. Cutting a hair into four fits perfectly into this tradition; it’s visually striking and carries an inherent humor because of its over-the-top nature, making the expression more memorable. English, by contrast, tends to be more pragmatic. "Splitting hairs" conveys the idea efficiently without specifying how many pieces the hair is divided into. It’s straightforward, much like many English idioms.

So, while the English are content with splitting hairs, the French take it a step further by cutting them into four. It’s not just about precision, it’s about being extra.

The oldest records of the English expression date back to the 17th century, so one might speculate that English borrowed it from French - and the French, in turn, might have swiped it from Italian or Russian, where hairs are also subjected to the cruel fate of being split into four.

English idioms often favor brevity (why use four words when two will do?), so if the phrase did come from French, it makes sense that the English gave it a little trim. Interestingly, German, Dutch, and Spanish also just split hair, no extra divisions necessary - so maybe English borrowed from them instead. At this point, it seems like everyone was too busy dissecting hairs to keep track of who said it first!

To illustrate this, imagine an English philosopher, a French mathematician, and a barber (from anywhere) walking into a salon. The philosopher muses, "To cut or not to cut, that is the question." The mathematician responds, "If we cut one hair into four, we can achieve perfect symmetry!" The barber, scissors in hand, sighs and says, "Messieurs, I just work here."

Usage Example:

Arrête de couper les cheveux en quatre, c’est une décision simple !
Stop splitting hairs, it’s a simple decision!

Avec lui, chaque décision prend du temps, car il coupe toujours les cheveux en quatre.
With him, every decision takes time because he always splits hairs.