The evolutionary answer seems to be that there is a tradeoff between the ability to learn and imagine — which is our great evolutionary advantage as a species — and our ability to apply what we’ve learned and put it to use. So one of the ideas in the book is that children are like the R&D department of the human species. They’re the ones who are always learning about the world. But if you’re always learning, imagining, and finding out, you need a kind of freedom that you don’t have if you’re actually making things happen in the world. And when you’re making things happen, it helps if those actions are based on all of the things you have learned and imagined. The way that evolution seems to have solved this problem is by giving us this period of childhood where we don’t have to do anything, where we are completely useless. We’re free to explore the physical world, as well as possible worlds through imaginative play. And when we’re adults, we can use that information to actually change the world.

— Alison Gopnik, talking about her book, The Philosophical Baby

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