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.

Children are the most amazing thing in the universe, as far as I'm concerned. If you're worrying about how it's going to turn out, you aren't experiencing that day-to-day satisfaction of being with these incredible, extraordinary creatures. Every single one of them is the most incredible, extraordinary creature that you're ever going to want to see. I think the joy of having that deep relationship - that's the core of what being a parent is.

Philosophers and psychologists have long puzzled over the question of how we know as much as we do despite our limited experiences. One way is to see how children learn. Another example is consciousness. The concept is usually explored by armchair academics. Looking at kids expands our conceptions of consciousness.

If parents are the fixed stars in the childs universe, the vaguely understood, distant but constant celestial spheres, siblings are the dazzling, sometimes scorching comets whizzing nearby.

The youngest children have a great capacity for empathy and altruism. There's a recent study that shows even 14-month-olds will climb across a bunch of cushions and go across a room to give you a pen if you drop one.

Putting together philosophy and children would have been difficult for most of history. But very fortunately for me, when I started graduate school there was a real scientific revolution taking place in developmental psychology.

The best scientific way to discover if one factor influences another is to do a controlled experiment.