The Neptunian Journey
Last and First MenThis flow traces how repeated Neptunian failures give way to deliberate human redesign and, eventually, the shared consciousness of the Last Men.
increasing
Bearing strength in each event
decreasing
An Unfit Landing

Ninth Men on Neptune
A rushed design
The Ninth Men reach Neptune as a fragile miniature of their makers, poorly suited to gravity, climate, and geological violence. Their inherited civilization cannot withstand the planet’s conditions.
Return to animal life
Civilization disintegrates, and the settlers’ descendants become subhuman forms adapted to Neptune. The failure demonstrates the danger of designing for an imagined environment rather than the real one.
The Tenth Men Reappear

A New Human Beginning
Adaptation through necessity
A rabbit-like precursor escapes predators by entering dense scrub. Digging, climbing, and experimenting with new food gradually develop its hands and behavior.
A species returns
The altered animal becomes the Tenth Men, recovering human-like social life through a different evolutionary route. Their emergence begins a long, uneven Neptunian human history.
The Long Fluctuation

Repeated Civilizations
Rise and reversal
Successive Neptunian human species build societies, lose them, and return to primitive life. Disease, social conflict, and biological weakness repeatedly interrupt progress.
A persistent limitation
The Fourteenth Men endure for an immense span but remain trapped by their own imperfect nature. Their history shows that survival and intelligence alone do not ensure spiritual advance.
A Deliberate New Direction

The Fifteenth Men
A durable civilization
The Fifteenth Men establish a world community grounded in human development. They confront disease, labor, aging, misunderstanding, and ill-will as linked problems.
Remaking becomes purpose
Rather than accept humanity as a fixed natural product, they make improvement of the species a sustained social project. Their work initiates the more deliberate transformations of later Neptunian history.
Collective Awakening

Individuals and the Racial Mind
Minds in relation
The Eighteenth Men use intimate sexual groups to form group-minds, each enriched by distinct personalities. Rarely, the whole population awakens as a racial mind.
A vision beyond the individual
In this shared state, humanity perceives its past and cosmic setting with extraordinary breadth. The experience guides society, even though individuals cannot retain its full insight after returning to ordinary consciousness.
After the Solar System’s collision with a dark body
About 300 million years after the solar collision
Across the first 600 million years on Neptune
Near the end of the Neptunian preparatory era
In the age of the Eighteenth Men