Becoming an adult means leaving the world of your parents and starting to make your way toward the future that you will share with your peers.

Young children seem to be learning who to share this toy with and figure out how it works, while adolescents seem to be exploring some very deep and profound questions: how should this society work? How should relationships among people work? The exploration is: who am I, what am I doing?

All of us gardeners know that nothing comes out the way you planned. It's a different garden every year, and it's always sort of different from what you were thinking when you began. What it really means to be a good gardener is to work hard to produce an ecosystem that will have enough diversity, enough possibilities, so it's robust, and it's resilient, and it can change when the seasons change. And that kind of robust, unexpected, variable, messy system - that's what you want to create when you're having children, too.

Adults often assume that most learning is the result of teaching and that exploratory, spontaneous learning is unusual. But actually, spontaneous learning is more fundamental.

The brain knows the real secret of seduction, more effective than even music and martinis. Just keep whispering, 'Gee, you are really special' to that sack of water and protein that is a body, and you can get it to do practically anything.

Teaching is a very effective way to get children to learn something specific - this tube squeaks, say, or a squish then a press then a pull causes the music to play. But it also makes children less likely to discover unexpected information and to draw unexpected conclusions.

Ineffective or weak brain connections are pruned in much the same way a gardener would prune a tree or bush, giving the plant a desired shape.