Before being able to usefully occupy oneself with combating an evil, one must know its cause.

Thus, seeking the primary cause of war is the first step in preventing it.

So if we go back over the chain of causes and effects scientifically that result in the outbreak of a war we finally find a primordial cause from which all others flow: overpopulation, i.e., the excess of population in one or several territories, each subject to a different national solidarity.

Undertaking in this way an investigation of the causes of wars, working back from the final physical cause to the original, natural cause and logically drawing a preventive system from it, is what I call “scientific pacifism” (it is only after doing this that one can indulge in metaphysical divagations). This is in opposition to the pacifism of sentimental or mystical pacifists, who think that they will transform their wishes into realities with beautiful and noble words. This is also in opposition to the pacifism of incomplete pacifists who, while being animated by a spirit more realist than those previously mentioned, stop at a certain point in their search for the causes of war.

Unfortunately, until now there have been few scientific pacifists who have noted or admitted the existence of overpopulation as the primary cause of war.

The others, men of good will, though insufficiently enlightened, by attributing an exclusive or exaggerated importance to secondary facts, hinder rather than accelerate the solution to the problem of universal peace. For example, they account for the evil of war by the natural pugnacity of man, i.e., his combative instinct; by his contempt for the lives of others, i.e., a vulgar and poorly understood egoism; by the patriotic sentiment, by nationalist doctrines, by the authoritarian basis of society, by the capitalist regime, etc. factors which certainly contribute to a greater or lesser extent to the blossoming of war, but none of which are the fundamental cause.

The lack of understanding is even worse if we take simple souls into consideration. They take apparent and superficial causes of wars for their real causes. An example: The war that resulted in the conquest of Algeria by France was declared following a blow with a fan delivered to the French consul by the dey of Algiers. There are those who believe that this was the cause of that war and that if France took control of Algeria it was to punish the dey. History as it is taught in schools is a method for inculcating similar ideas on the causes of past wars. But what clear-sighted man doesn’t realize that this insult, likely provoked, was only the pretext and the occasion for the declaration of war, and that the wish to convert Algeria into a colony was the real reason?

The reason given by Pascal in a famous witticism does little more to explain the true cause of war: “Why do you want to kill that man?” — “He is my enemy: he lives on the other side of the river.” In truth, this is a very superficial reason. The potential hatred between two peoples is the consequence of something other than the geographic location of their countries.

Who thinks that the Sarajevo affair was the real cause of World War I? It was a moment in time which it is convenient to stake as the starting point in writing a history of that war, but a simple examination of the reasons for the assassination of the Archduke of Austria shows that that event was the effect of the rivalry between a Germanic and a Slavic nation in the Balkans, a primary rivalry which, once resolved in war, dragged in other rivalries. And what were the reasons for these rivalries? Economic reasons, obviously: these no longer need be proved. And it is here that the most advanced of incomplete pacifists I spoke of above stop.

But economic rivalry does nothing but translate the antagonisms in the vital needs of peoples. Behind the economic fact there lies the biological fact: the reproduction and multiplication of humans and their need for food.

Behind World War I there lay European overpopulation.

The Sarajevo affair was the push that set in motion a machine that was ready to roll.

We could proceed to an analysis of the determinism of all wars. We would first discover in them the economic reasons, and then the biological ones. And finally we would find the phenomenon of overpopulation as the primordial cause of war.

What then is overpopulation?

Before giving the definition I must say a few words on that natural law that is called the law of population or Malthus’ Law, from the economist who discovered and formulated it.

It consists in this: that the population, if no obstacle prevents it, indefinitely increases geometrically, while the quantity of subsistence goods that a given amount of land can produce is necessarily limited. In order to make clearer the contrast that exists between the principles of reproduction of humans and that of the production of their foodstuffs, Malthus said that produce can only increase arithmetically. The increase in subsistence goods can no longer be so rigorously calculated, because of the application of science to agriculture, but this has very little importance and has no influence on the truth of the law of population, whose formula is the following: The population has a consistent tendency to grow beyond the means of subsistence.

So there is, in principle, a natural disequilibrium between the reproduction of humans and the production of their foodstuffs.

Nevertheless, in the end a relative equilibrium establishes itself as best it can by means of what Malthus called brakes to population. They can occur in a way favorable to man, but until now it is in an unfavorable way that this has occurred, i.e., this equilibrium has until now been more apparent than real.

Malthus distinguished two kinds of brakes: first, the preventive (celibacy and continence) which he considered good because according to him they were moral, and prostitution and procreative prudence, which he considered evil, because according to him they were immoral; second, the repressive (all the causes of premature death).

If we part from Malthus in his appreciation and classification of brakes — as I personally do — it is because they no longer correspond to the scientific wisdom and ethics of our times. We can say that there exists but one preventive brake, because there is only one that is admissible: procreative prudence, or the limitation of births, while there exist many preventive brakes, all of which can be determined. The preventive brake procures an equilibrium of wealth and happiness; the repressive brakes give an equilibrium of misery: poverty and suffering.

The preventive brake, that which foresighted humans carry out in order to avoid the arrival of new beings whose food is not assured, is of fundamental importance in the prevention of war. But the foresighted are a tiny minority of humanity, and so war rages frequently.

The repressive brakes are those used by nature when man fails to put into effect the preventive brake. And among them can be found the one that occupies us at this moment: war.

The choice offered to humanity is thus clear: either war or the limitation of births...

If wisdom has manifested itself in the matter of procreation in a given country the population finds itself exactly limited to the food capacities of its own soil. But this country only exists in theory. As soon as this country exceeds this limit it is in a state of agricultural overpopulation.

Its population continuing to grow, what then is it forced to do in order to preserve its mode of existence? It is forced to give itself over to industrial production in order to engage in commerce with foreign countries, i.e., to deliver manufactured products to them in exchange for their produce.

But this evolution of agriculture towards industrialism is not limited to one country. It is occurring with greater or lesser speed in all the old countries, as Malthus said, in all the countries with old civilizations, especially in Europe. In Asia countries like India, China, and Japan, which are extremely overpopulated, are on the road to industrialization. The United States, which is, despite it all, a new country, began to industrialize a long time ago, as well as to seriously limit immigration, going so far as to ostracize one of the most prolific or peoples: the Japanese.

The industrial countries thus enter into competition for the placing of their products. Generally this commercial struggle becomes envenomed and engenders hatred among peoples. In order to have greater opportunities to sell their merchandise nations naturally desire privileged markets. Commercial treaties granting preferences to more favored nations bring in their train the enmity of others. But the privileged markets par excellence are colonies, which are obtained through wars, and are powerful causes of international jealousy, the mother of war. For example: the Franco-German disagreement on the subject of Morocco. What is more, in their colonies the old countries obtain at a better price than elsewhere products that they lack as well as primary matter necessary for their industry. They find in them an issue for a portion of their excess population. Often, they also find the cannon fodder in them needed to confront the wars their colonization is likely to give birth to.

As we see, these commercial rivalries are in the end nothing but struggles for food and the preservation of a certain type of existence. Well then, it is these commercial rivalries, these struggles for food which engender war. In the first place they create in peoples a mood favorable to the declaration of war, as was verified in 1914. And they unleash war so to speak naturally.

In ancient times wars, as is the case today due to overpopulation, took on the aspect of rapid invasions of territories accompanied by pillaging and the reduction of the inhabitants to slavery. Things were clear and simple. Today their determinism is formed by a series of phenomena far more complex and tangled, and they are masked in hypocrisy. But the two determinant reasons have not changed: reproduction without hindrance and food.

All of this is obviously hardly poetic, but it’s the truth and it must be told...

World War I was nothing but a vast war of overpopulation, dissimulated in order to capture and sustain the sympathy of the peoples fighting in each camp under great idealistic words: war of right on one side, war of kultur on the other. In reality, a struggle for existence between over-populated nations of various degrees... In the future, when this conception of the causes of war will be shared by greater and ever growing number of people, the responsibility of belligerents in a war will be measure by their over-population...

It goes without saying that a rationally normal society is one in which there is no over-population, thus where an equilibrium of wealth and happiness reigns between the people and its subsistence goods. This is what the German economist List called a “normal nation....”

This then is the formula for economic autonomy for a nation. It is clear that a nation that sticks with this reduces the risks of war to a minimum. In fact, it will never engage in any war of aggression; it will have no designs for conquest or colonization. What is more, it will not contribute to over-populating another country through an emigration which, however peaceful it might be in appearance, always creates ascertain hostility. All that will remain for a “normal nation” is the danger of an invasion of its territory, either by immigration or by war, on the part of one or several other over-populated nations.

But if all countries imitated it the danger of war would be averted.

If we extend this idea of the “normal nation” to the entire planet we obtain the idea of world-wide economic harmony.

When this harmony is realized — which we are far from obtaining — and only then can the mystical pacifists, Christian and others, say to peoples and individuals: “Love each other,” or “Thou shalt not kill” without repeating vain words. In truth, they will not need to say anything: their speeches will have no object. In any case, they won’t have made this possibility a reality: it will have been born of the labor — in thought and deed — of scientific pacifists...

In summary, the maximum population each country is allowed to reach without its inhabitants suffering and without causing suffering to other countries, is the number of human beings who would be assured the ration of subsistence goods necessary to normal human existence by the soil of that country.

Over-population begins beyond this figure.

And so, overpopulation is the primordial cause of war.

This fact indicates to us the preventive remedy for this ill: suppressing or preventing overpopulation in each country.

Phrased differently: establishing a true equilibrium between the population and subsistence goods.

The sole method: the limitation of births...

Governments dispose, in fact, of means of encouraging and discouraging overpopulation. What is more, among human beings reproduction is entirely under the control of this will. Which is to say that both governments and individuals, having the necessary powers at their disposal, war could be abolished if they truly wanted it...

Consequently, we scientific pacifists demand a world-wide limitation on births, affected by all nations leagued together in a desire for peace under the leadership of the League of Nations.

This is the primary propaganda to be done by pacifists, for humanity’s salvation resides in this solution.

London. April 1925