A person who is app-dependent is always searching for the best app; and as soon as its routine has been executed, the person searches for the next app. A person who is app-enabled also uses apps frequently. But he or she is never limited by the current array of apps; apps will free the person to do what he or she wants to do, or needs to do, irrespective of the next application of the app. An app-enabled person can also put devices away, without feeling bereft.

No academic ever expects to be taken seriously by more than three other people, because really, we write for three people in our field.

Teachers must be encouraged - I almost said 'freed', to pursue an education that strives for depth of understanding.

Teaching which ignores the realities of children will be rejected as surely as any graft which attempts to ignore the body's immune system.

Twenty-five years ago, the notion was you could create a general problem-solver software that could solve problems in many different domains. That just turned out to be totally wrong.

As a planet, we are at risk of destruction (for example, gradually by the warming of the planet; or rapidly, by nuclear war or a pathogen that gets out of control). And these threats require us to work together, and not just to announce our diversity.

It's not how smart you are that matters, what really counts is how you are smart.