The Creation of the Fifth Men was the culmination of the Fourth Men’s prolonged attempt to design a new human species. The first Fifth Men were opposite-sex identical twins, produced in laboratory conditions from a single fertilized ovum. Their creation joined deliberate biological design to a strikingly singular origin: the new species began with two individuals whom the narrative presents as its Adam and Eve.

The design problem

The project began with an ambition to create beings capable of a higher order of mentality than the Fourth Men themselves. The Great Brains could not draw on personal experience of love, art, religion, or the life of individual spirits; they had to infer the importance of those experiences from their study of the Third Men and design an organism capable of them. The challenge was not simply to enlarge the brain. The designers believed that an individual human brain could not safely exceed a certain weight, so they sought a new organization of human capacities rather than unlimited growth of a single organ.

The design also had to accommodate a long life without eliminating the formative importance of sex and parenthood. The intended lifespan, measured in thousands of years, made procreation necessarily rare, yet the Fourth Men judged both sexual experience and parenthood essential to full mental development. Their solution included a greatly prolonged infancy and childhood, extending the mature adults’ experience of parenthood while giving the new beings time for physical and mental growth. Childbirth was designed to be as easy as among the Third Men, and the improved physiology was expected to reduce the intensive care that had burdened mothers in earlier species.

Centuries of research and failure

Even preliminary specifications took many centuries of research and calculation. The Fourth Men then entered a lengthy period of experiments in producing the intended type. For thousands of years, much of the work consisted of discovering that promising approaches led nowhere. The effort was also interrupted by disagreements among the Great Brains over policy; on one occasion, opposing parties resorted to chemicals, microbes, and armies of human automata. The creation was therefore neither an immediate triumph of technical mastery nor a smooth, unified undertaking. It emerged from repeated failures, periods when the project was neglected, and conflict among the very minds directing it.

At last, the Fourth Men produced two individuals almost precisely matching their original design. The laboratory origin and shared fertilized ovum made the pair identical twins, while their opposite sexes gave the new species its founding male and female. The account frames them as the Adam and Eve of the Fifth Men: not the result of an unplanned appearance in the wild, but the deliberate beginning of a species after an extended program of design and experimentation.

The bodies of the first Fifth Men

The Fifth Men are described as the first to attain true human proportions of both body and mind. On average, they stood more than twice as tall as the First Men and were much taller than the Second Men. Their immense lower limbs and broad feet supported their great stature, while their powerful arms and shoulders were also shaped for fine control. Their hands combined strength with precision: the thumb and forefinger formed a formidable grip, and a delicate sixth finger had a tip divided into two small fingers and a corresponding thumb.

Their bodies were hairless apart from a close, thick skull-cap, ruddy brown in the original stock. Their brown skin maintained an even temperature in tropical and subarctic climates without hair or clothing. The first pair had immense, deep-violet eyes and strongly moulded, mobile features. Those facial characteristics had not been specifically designed, since the Fourth Men considered them unimportant; biological forces nevertheless produced faces reminiscent of the Second Men, with an expression the narrative describes as unprecedented. Their brain capacity was twice that of the Second Men, but their relatively small heads show that the design did not simply reproduce the earlier species’ pattern of an increasingly oversized brain.

Significance and legacy

The creation marks a change in how human development is represented: the Fifth Men did not appear solely through the slow emergence of a new variety, as the Second Men had after the biological variations that followed the Patagonian disaster. They were fashioned through conscious specification, prolonged calculation, and laboratory production. Yet the undertaking remained vulnerable to uncertainty: thousands of years of failed experiments and divisions among the Great Brains preceded the successful pair, and the first Fifth Men’s unplanned facial traits attest that design did not wholly control biological outcomes.

The founders’ origin also establishes the species’ reproductive and familial problem at its beginning. Two individuals could inaugurate a population, but the Fourth Men’s design had to make parenthood meaningful in a species expected to live for thousands of years and reproduce rarely. Prolonged childhood was therefore part of the project, not an incidental stage after birth: it was built into the species’ development and into the mature generation’s role as parents. The event stands both as an act of biological creation and as an effort to make a new form of human experience possible.