No one can persuade another to change. Each of us guards a gate of change that can only be opened from the inside. We cannot open the gate of another, either by agreement or by emotional appeal.

So long as we need to control other people, however benign our motives, we are captive to that need. In giving them freedom, we free ourselves.

By definition, revolutions are not linear, one step at a time, event A leading to event B, and so on. Many causes operate on each other at once. Revolutions shift into place suddenly, like the pattern in a kaleidoscope. They do not so much proceed as crystallize.

Real progress in understanding nature is rarely incremental. All important advances are sudden intuitions, new principles, new ways of seeing.

It's not so much that we're afraid of change or so in love with the old ways, but it's that place in between that we fear . . . . It's like being between trapezes. It's Linus when his blanket is in the dryer. There's nothing to hold on to.

Over the years your bodies become walking autobiographies, telling friends and strangers alike of the minor and major stresses of your lives.

Risk always brings its own rewards: the exhilaration of breaking through, of getting to the other side; the relief of a conflict healed; the clarity when a paradox dissolves.