The Expression of the Emotions in Man and Animals by Charles Darwin, was published in 1872. It was very controversial at the time, and for a long time afterwards for two reasons.

Firstly it implied a continuity between the expression of some sentiments with people and beasts ... as though we are somehow related!

Secondly it implied a hardwiring of our expressions – a biological lingua franca that bridged gender, race, geographical distance, culture and time. You can’t make up your own smile or your own frown any more than you can make up your own fingers. They’re simply there, biological mechanisms which universally fit a purpose across a species.

This issue, of intrinsic facial expressions, was still being argued about through the twentieth century. But repeated work done across cultures including with very isolated peoples finally demonstrated that humans all frown, grin and sneer in the same way for the same reasons.

Pop psychologists and inspirational speakers often remind people of how important the physical component of our presentation is when we communicate. Albert Mehrabian’s 7% spoken words, 38% voice tone and 55% body language is probably the most oft cited, although these figures come with their own caveats which he stated but are not often repeated.

However, whether we can put a consistent percentage value on these things is irrelevant. The fact is that physical presentation matters. It nuances and assists verbal content. Look at how, disembodied through cyberspace, we still use emoticons on digital communications :-D

Evolution simply doesn’t take time and effort to produce highly complex, utterly useless systems.

In fact, seeing a discontinuity between facial expressions and verbal output puts us on alert. Nietzche wrote:

"One can lie with the mouth, but with the accompanying grimace one nevertheless tells the truth"

And watching another’s expressions can help us to empathise. As Edgar Allen Poe had it:

“When I wish to find out how wise or how stupid or how good or how wicked is anyone, or what his thoughts are at the moment, I fashion the expression of my face, as accurately as possible, in accordance with the expression of his, and then wait to see what thoughts or sentiments arise in my mind or heart”

And perhaps we’re not the only species sensitive to the facial expressions of other humans. A team at Lincoln University led by Dr Kun Guo discovered that dogs have left gaze bias when looking at human faces – not other objects or other animals - just humans. The idea is that we may reveal our emotions more authentically on the right side of our faces and gazing left helps the dog to intuit the human state better. Probably more work needed, but it’s an intriguing notion. If we attain simpatico through our facial expressions, why should our longest serving friends not have got in on the act?

The modern master of facial studies is probably Paul Ekman, a professor of psychology at the University of California Medical School. With his colleague Wallace Friesan, he catalogued the 43 distinct muscular movements that the human face can make with its over 52 muscles, calling them action ‘units’. Taking combinations of up to five action units at a time, they catalogued over ten thousand combinations and then noted the three thousand which meant something, the reflection of an authentic human state.

The face is simply the most exquisite piece of biological communication machinery in existence. Can you think of a better one?

In this light, it hard to see how deliberately covering a face can be seen as less than an assault on personality, on individuality. It’s an attenuation of a person’s relationship with the world and the other people in it, a hobbling of the natural medium through which we emote and communicate, even when not speaking.

This week, French MPs voted to pass a law which will forbid the wearing of facial covering in public places. This will, no doubt, be distressing to people who wear motorcycle helmets to restaurants and balaclavas to the theatre. But its real intention is to forbid the wearing of the veil by a minority of muslim women.

Given what we now know about faces, shouldn’t we all regard this is a virtuous law?

I don’t think so.

The Harm Principle' is one of the principles upon western liberal thought is based. As John Stuart Mill wrote:

“… the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others”

It’s difficult to see how the wearing of a veil harms others.

There are exceptions of course. Minors shouldn’t be able to wear a veil any more than they should be able to get a tattoo. In sensitive security situations such as passport control or entering buildings, people must be required to show their faces. In professional situations such as teaching, there must be no impedance of communication and therefore no veil.

But if a woman chooses to walk down the street completely covered, that surely must remain her own business.

Of course, she may be being coerced by a man. The proposed French law places far lighter penalties upon women than on the men who force them to wear veils.

But considering this situation carefully, how on earth could the law prove coercion without a full disclosure from the coerced? It’s probably unworkable.

At its worst, this law could further restrict the free movement of women who are subject, for economic or social reasons, to the dress codes imposed by husbands and fathers.

It’s hard to see what the French law will achieve but resentment. It’s unlikely to move the willing veil wearer to a secular philosophy, to move the oppressed veil-wearer to liberty or to move marginalised muslims to fuller integration with French society and values.

In my view, as a personal practice, the wearing of the veil is to be deplored: and the French law looks like sanctimonious bullying.