Eighteenth Men

The Eighteenth Men occupy the far end of an immense history of human succession: eight species preceded the Neptunian era, and ten more have succeeded one another or existed contemporaneously on Neptune. The account places them within a story measured not by individual lives but by hundreds of millions of years, in which humanity repeatedly loses, recovers, and reshapes what it means to be human.

Identity in the Human Succession

The Eighteenth Men are named as the Last Men of the account’s present, the final species in its count of eighteen. The historical survey sets their place against the fortunes of eight earlier, pre-Neptunian species, followed by ten species associated with Neptune. Those ten did not necessarily appear in a simple succession: the narration says they succeeded one another or were contemporary on Neptune’s plains.

The earlier record is uneven. Some of the eight pre-Neptunian species remained primitive; many reached civilizations that were confused and fleeting. The Fifth Men stood out as brilliant, already awakening into true humanity when misfortune crushed them. This history makes the Eighteenth Men the endpoint of no smooth, guaranteed ascent: the species before them could achieve much and still be cut short.

Humanity’s Neptunian Ordeal

The ten Neptunian species display an even wider range, extending from instinctive animal existence to forms of consciousness never before attained. The account locates most definitely subhuman, degenerate types in the first six hundred million years of humanity’s life on Neptune. During the earlier half of this preparatory span, a hostile environment nearly eliminated humanity. People gradually spread across Neptune’s vast north, but the narrative stresses the distinction between human beings and human animals: the north was populated by beasts, not by men.

During the latter half of those six hundred million years, the human spirit slowly awakened again. Its recovery was not steady; it followed the fluctuating advances and declines characteristic of the earlier ages. The lengthy preparatory era therefore contains both biological endurance and a prolonged interruption in humanity as a fully human presence.

The Long Advance Toward Maturity

After this six-hundred-million-year preparation, the account describes the last four hundred million years of humanity’s Neptunian career as a period of almost steady progress toward full spiritual maturity. That qualification matters: the advance is nearly, not absolutely, uninterrupted, and it follows an immense stretch in which survival came before human flourishing.

The Eighteenth Men’s place in this chronology gives their identity its significance. They inherit a history whose civilizations have been fleeting, whose species have ranged from primitive forms to unprecedented consciousness, and whose recovery from near-extinction took hundreds of millions of years. The passage presents them not as proof that progress was inevitable, but as the late outcome of a history in which humanity could repeatedly fail to remain human before moving, at last, toward maturity.