From his psychoanalytic theory on impulse, Freud replied,

"In human impulse, there is an impulse to preserve and unify (eros) and an impulse to destroy and kill, the latter with two facets: an instinct to attack and an instinct to destroy. These impulses are necessary in every person; they feed each other and oppose each other, thereby resulting in the many manifestations of life. If humans engage in war because of the destructive impulse, then we must summon the opposite impulse, eros. All that which promotes the bonds between people's emotions and minds is that which hinders war.

There are two kinds of emotional bonds. One is the bond with that which is loved and the other arises from a sense of togetherness and belonging. If there is significant similarity and commonality between people, there can be connection at the emotional level. Such connection is a powerful support of human society."

Because of the advance of culture, there have been significant and many changes for the human mind. Freud wrote on the role of the intellect as well.

"One of the more remarkable phenomena born of human culture is the heightening of the intellect. A strong intellect controls the impulses. Rejection of war is not simply rejection on the level of intellect alone, nor only on the level of emotion. Pacifism is rejection that comes from deep within the body and mind. I don't know how long it will take for all of humanity to be pacifist. However, the mind that can be born from the development of culture and wariness of future crises of war - these give me hope that humanity will move toward a future without war soon. I don't know what kind nor which route we will take on this journey, but I hope I can say just this - if the development of culture is encouraged, we will be able to see the end of war!"