Our body is a constant reminder of the fact that we share our origins with many other species, as Neil Shubin describes it so well in his book “Your inner fish”.

The basic plan for members has remained the same in all existing species and this ever since a strange kind of fish called tiktaalik was literally doing pushups with his proto-forelegs in shallow waters. The common plan for members has since been the following: First one bone, corresponding to our thigh or arm, then two bones corresponding to our leg or forearm, then a bunch of small bones corresponding to our ankle or wrist, to finish with a variable number of “fingers”.

It is also amazing to see that the gene allowing our fingers to be different from one another is the same one that allows sharks to develop their bony fins, and the same one also that can be found in birds for wings formation. Stranger still, the process for developing teeth, scales, hair, feathers, sweat glands and…mammary glands is the same one, and this in all species: the same bunch of genetic switches are activated to make them grow. To cut short, the bodies of all animals are nothing but variations on the same themes.

Starting there, it is not so strange to assume that our human psychology is also a living memory of our family ties with other species. We usually tend to think that we, humans, possess moral qualities that place us well above the rest of the living species: the power to see beyond our little selves, to fight our selfish tendencies, to get closer to the good and further away from our bestial nature. This idea has been reinforced by certain religions, representing greed as a clever and powerful demon, creeping inside us, that we can only try to push away if we can.

This conception is also suggested in Richard Dawkins’ selfish gene theory, which makes our biology into gene replicating machines, acting only in the aim of maximizing our chances to pass them onto next generations, uncaring about the fate of others, even if Dawkins also suggests that it is our choice to fight against that reality. Once more, our capacity for rational decisions, specifically human, is supposed to raise us well above the selfish preoccupations imposed by our evolutionary past.

But is our biological inheritance only a selfish one? First of all, the selfish gene theory does not necessarily exclude altruism, which can act as an insurance policy against situations where one can need other people. In a reciprocal frame, it insures individuals who act this way with a more stable and harmonious society, with the hope to be helped when the need arises. Such reciprocal situations are often found in primates.

But the care for others seems to go beyond reciprocity. In his last book, "The Age of Empathy: Nature's Lessons for a Kinder Society”, Franz de Waal shows that we share much more than just biology or behavior with other species, and that man is far from being the only “moral animal”. Many of the species closest to us, like chimpanzees or capuchins, act with spontaneous and obvious sense of justice, which expresses itself in two ways in a given individual: The first is an evident preference for situations where his companions receive, as he does, a remuneration.

The second is anger in situations where a companion receives more that he does, without having deserved it, going as far, in such cases, as refusing his retribution altogether. A behavior that sounds familiar to the French citizen I am: they simply go on strike!

So there seem to be two sides to the feeling of justice that apes demonstrate: equity between all pairs on one side, and merit-depending reward on the other. It is interesting to note that both sides tend to reflect the left and right-wing policies around which democracies seem to alternate or to oscillate more or less. It does indeed seem fair that everybody has the same rights, but it also seems just as fair that those who produce more effort are rewarded for it. Sticky issue which leaves us with the difficult task to decide what are these rights to which everybody can claim (the place of birth in itself having a huge influence on the chances of one individual to succeed), and to judge the value of the effort or merit of those who claim it, which is far from being a clear in the context of market economy.

But let’s go back to our apes, and to the common ancestor we share. It seems that just as well as selfishness, empathy and sense of justice are both part of our heredity. And the way we act towards others does not just come from our education or our superior cognitive capacities. Our body, through our emotions, often shows us the direction our conscience ends up choosing and this without us being aware of it in many cases. We usually call this intuition. Of course we can also, for any reason, act in the opposite way to the one our emotions tell us. But who has never felt physical unease faced to the pain of someone else? It is our body, as in other species, which make us feel for others in the first place. De Waal clearly explains this and isolates three layers of empathy which could have evolved, one after the other, in animals.

The first layer is at the base of what allows us to care for others, and is found in the emotional contamination which can be seen in many animals, included human newborn which often start crying as soon as they hear the cry of another one. Mice themselves are more sensitive to pain if they are witnessing another mouse in distress. We humans can easily feel anxious while watching a tightrope walker whose foot has just slipped, or cry like a baby when faced with a movie character involved in a dramatic situation. The recent discovery of mirror neurons, which are activated in the brain of someone watching a scene, in the same area as in the brain of someone acting the scene, could well teach us more on that subject.

This takes us to the next layer, which is the will to comfort someone in pain. Occurrences of comforting behaviors are so common in animals, for example grooming or cuddling in apes, that their importance in social relationships makes no doubt, even though it is more frequent amongst family of friends.

The final layer of empathy is targeted help, customized to resolve the problem of another individual. It supposes some kind of perspective of the other one’s needs, in order to fulfill those. It is certain that Man has the greatest capacity to analyze a situation, and to put oneself in someone else’s shoes. But other species are also capable of this, and without necessarily expecting reciprocity, as in the seen situation of a chimpanzee desperately trying to help a baby bird to fly. This will to resolve problems of others has also been shown to some extent in canines. Clearly, nature has provided some species with real qualities of empathy and altruism, set up by successive layers in the course of evolution. The body is the first to show the way in each of these steps, through emotions or intuition, well before a hypothetical strategic plan. The difference between Man and animals seems once more to be a simple question of degree.

But in that case, how do selfish and empathic sides cohabitate in the species who possess them? The care for others cannot express itself in any situation of course, or with anybody, otherwise our life would become a hell where the pains of the entire world would take up our entire existence. A dose of selfishness is therefore potentially and necessarily present. But when is that, and how? The switch for empathy, in Man as in chimps or even mice, seems to be turned on by identification or familiarity with another individual. The closer, or the more similar two individuals, the more easily empathy will arise between them. Male s in a competitive situation do not identify with their opponent and the rival’s pain seem in that case to generate pleasure rather than pain. But in other situations, males or females tend to feel the pain of another to which they identify, on the condition that they are visually witnessing the situation or that they are able to mentally represent it. The detailed description of somebody’s torture is often unbearable to us, as soon as we mentally identify to the person in question.

But since we talk about torture, let’s talk about war. How can it possibly exist if we feel so easily the pain of others? It is surely possible, in certain situations, to consciously turn off the empathy switch, as nurses have to do for example, or as Nazis having voluntarily massacred innocents also had to. But we must realize that decisions in war are mostly made by powerful people in the safety of their offices, with no need to face the emotions resulting from having to kill someone else. Soldiers, for their part, only obey orders and do not kill as easily as war movies make it think. During World War Two, only one in five American soldiers did actually shoot the enemy. And during Viet-Nam war, it has been estimated that US soldiers used more than 50 000 cartridges for 1 actual enemy killed, the other ones having in all likelihood been shot in the air.

At the end of the day, our nature has given us a potential for selfishness, but also a good dose of empathy ready to be triggered, especially in the presence of individuals known or alike to us. We are animals to which rank, territory and food security justify war but we are also sensitive to injustice, willing to cooperate, and essentially pacifists. One or the other aspect will take the advantage depending on the circumstances. So what I wonder is whether we still have that much merit worrying about the good of others, if other species do it spontaneously as well… And when the pain of someone else is unbearable, it could almost be considered as selfish to want to end it. In the end the line between altruism and selfishness remains a blurry one in most cases.