Over at the Wall Street Journal, Greg Ip calls attention to a new book by center-left thinkers Dean Spears and Michael Geruso about the coming baby bust and the prospect of depopulation. It’s called After the Spike: Population, Progress, and the Case for People. Ip highlights the main thrust of their argument, which is that people are resources, not liabilities:

Population growth actually makes challenges such as resource scarcity easier to solve. Assume a fixed share of people become idea generators: scientists, entrepreneurs or inventors. The greater the population, the more ideas.

Solving most problems also involves fixed costs. Developing a vaccine or a smartphone costs the same whether for one person or 8 billion. The bigger the population, the more such investments become financially feasible.

The most provocative argument that Spears and Geruso make for population has nothing to do with economics. “It’s better if there is more good in the world,” they write. “That includes good lives: it’s better if there are more good lives.”

Check out Ip’s column.