“In former days the struggle for existence was chiefly a struggle against nature, today it is primarily a struggle against other human beings.”

Source: The Book of Laughter and Forgetting

The Diary of Samuel Marchbanks (1947)

Source: On the Foreign Policy of the Soviet State

Source: You Get So Alone at Times That it Just Makes Sense

1900s, God Does Not Exist (1904)

Mutual Aid: A Factor of Evolution (1902)
Context: In the animal world we have seen that the vast majority of species live in societies, and that they find in association the best arms for the struggle for life: understood, of course, in its wide Darwinian sense — not as a struggle for the sheer means of existence, but as a struggle against all natural conditions unfavourable to the species. The animal species, in which individual struggle has been reduced to its narrowest limits, and the practice of mutual aid has attained the greatest development, are invariably the most numerous, the most prosperous, and the most open to further progress. The mutual protection which is obtained in this case, the possibility of attaining old age and of accumulating experience, the higher intellectual development, and the further growth of sociable habits, secure the maintenance of the species, its extension, and its further progressive evolution. The unsociable species, on the contrary, are doomed to decay.

God or Nothing: A Conversation on Faith (2015)

Speech, 1947. Quoted in Scott H. Bennett, Radical Pacifism: The War Resisters League and Gandhian Nonviolence in America, 1915-1963, Syracuse University Press, 2003.