In his 1932 The Doctrine of Fascism, Benito Mussolini quotes approvingly historian Ernst Renan for his “pre-fascist intuitions”:
“The maxim that society exists only for the well-being and freedom of the individuals composing it does not seem to be in conformity with nature’s plans, which care only for the species and seem ready to sacrifice the individual.”
In his 1784 “Review of Herder,” Immanuel Kant wrote: “nature allows us to see nothing else than that it abandons individuals to complete destruction and only maintains the type.” (37/53)
And in “Idea for a Universal History with Cosmopolitan Intent” (1784), Kant wrote: “It appears that nature is utterly unconcerned that man live well, only that he bring himself to the point where his conduct makes him worthy of life and well-being.” (31/20)
Also this from Kant’s “Speculative Beginning of Human History” (1786): “this path that for the species leads to progress from the worse to the better does not do so for the individual.” (53/115)
So: A connection from 18th-century philosopher Kant to 19th-century historian Renan to 20th-century politician Mussolini. It’s important to note that between Kant and Mussolini stand Hegel, Marx, and Nietzsche, all of whom developed the sacrifice-individuals-to-improve-the-species theme.
Further, both Kant and Mussolini state approvingly that nature uses war to improve the species.
Here is Kant: “Man wills concord; but nature better knows what is good for the species: she wills discord.” (“Idea …” 32/21)
Kant again: “At the stage of culture at which the human race still stands, war is an indispensable means for bringing it to a still higher stage.” (“Speculative …” 58/121) Note the “indispensable.”
And again: “Thus, thanks be to nature for the incompatibility, for the distasteful, competitive vanity, for the insatiable desire to possess and also to rule. Without them, all of humanity’s excellent natural capacities would have lain eternally dormant.” (“Idea …” 32/21)
Now Mussolini: “Fascism does not, generally speaking, believe in the possibility or utility of perpetual peace. It therefore discards pacifism as a cloak for cowardly supine renunciation in contradistinction to self-sacrifice. War alone keys up all human energies to their maximum tension and sets the seal of nobility on those peoples who have the courage to face it.”
Again, between Kant and Mussolini were Hegel, Marx, and Nietzsche, all of whom urged violence and war as necessary steps towards human progress.
The Kant essays are collected in Perpetual Peace and Other Essays, translated by Ted Humphrey (Hackett, 1983).
Here is an online version of Mussolini’s The Doctrine of Fascism, which was co-authored with Giovanni Gentile.
For more on the development of German political philosophy from Kant to the early 20th century, see “The Climate of Collectivism” and “The Crisis of Socialism,” which are Chapters 4 and 5 of my Explaining Postmodernism: Skepticism and Socialism from Rousseau to Foucault.