Civilization is easier to inherit than to notice. The power stays on. A surgeon learns a procedure from someone who learned it before her. Each achievement looks like a service delivered in the present, though underneath it is a chain of people accepting responsibility from other people.
Low fertility removes links from those chains unevenly. A large country can carry electrical engineering through one small cohort. A rare craft may disappear much sooner when its last practitioner has no apprentice. Consolidation preserves some work while making more of the inheritance depend on a few centers.
A small population may be extremely prosperous and still lack the scale to maintain every complex capacity at once. GDP per person misses that problem.
Knowledge needs successors
Modern knowledge is cumulative. Each generation begins with more to learn before it can reach the frontier. Benjamin Jones found that inventors have responded to this growing burden of knowledge through narrower specialization and larger teams. That arrangement produces extraordinary results. It also means fewer people can hold the whole of a technical system in their heads.
Research effort has had to rise to sustain progress in several fields. The study discussed earlier found sharply declining research productivity in semiconductors and medicine even as the number of researchers increased. Artificial intelligence may reverse some of that decline. I hope it does. People will remain responsible for testing its errors and choosing which problems deserve attention.
A billion people poorly educated and denied freedom may produce less discovery than a much smaller open country. Population must be formed into capable people who can cooperate. Low fertility reduces the raw number from which that formation begins.
Cultural transmission is more intimate. A recorded language remains alive while someone speaks it. Families do much of this casually. A child learns a recipe beside her grandmother and learns obligation by watching a parent keep one. An archive preserves the words for the next speaker.
Resilience requires spare capacity
Complex systems become fragile when every part is used. A resilient hospital keeps some beds open, and a resilient craft trains more than one successor. Aging and contraction consume that spare capacity. Care and maintenance become urgent, so experiments with distant payoffs are easy to postpone.
The same tension appears in long-term threats. Asteroid defense and pandemic preparation require specialists whose work continues beyond one political cycle. A smaller humanity might coordinate them better. It might also devote a larger share of its effort to caring for itself.
One generation of contraction can be absorbed through wealth and automation. After five, rare knowledge may be concentrated in fewer places. Ten generations alter the scale of countries. A hundred is too far away for a forecast, though people then will still receive whatever we managed to carry forward.
The thousand-year horizon belongs especially to expansion beyond Earth. Settling another world requires a community that can raise children and repair its machinery after the founding specialists are dead. A few astronauts can begin the mission. A civilization whose working assumption is fewer people in every generation will struggle to finish it, however impressive its rockets remain for a while.
Adaptation and direction
Adaptation is necessary. The age structure of the next few decades is largely set, and older people deserve security. Healthier aging and automation can make the transition far more humane. Refusing useful adaptations in order to heighten the crisis would be cruel.
Adaptation can also become a way of avoiding the larger judgment. A country may balance its pension system and automate its factories, then call the result sustainable. It may be sustainable for the forecast period. If each generation remains smaller, the same exercise returns with less room.
Adapting to a demographic inheritance is stewardship. Accepting contraction as humanity’s permanent direction gradually reduces the number of families and experiments through which the future can arrive.
A growing population is one condition among many for a great civilization. Every birth remains a gift rather than a debt owed to the state. Civilization is nevertheless carried by persons, including persons not yet here. Reversing fertility decline gives more of them the chance to receive their inheritance and build beyond it.
Citations
- Benjamin F. Jones, “The Burden of Knowledge and the ‘Death of the Renaissance Man’: Is Innovation Getting Harder?”, Review of Economic Studies 76, no. 1, 2009.
- Nicholas Bloom, Charles I. Jones, John Van Reenen, and Michael Webb, “Are Ideas Getting Harder to Find?”, American Economic Review 110, no. 4, 2020.