To live, an organism must metabolize: it must exchange matter and energy with its environment. Consequently, over the course of a year, many atoms in your body are replaced by new ones. The energy you use to get a drink of water comes from sunshine working its way up to you through the food chain – in a real sense, light lifts the cup to your lips. The apparent wall between your body and the world is more like a picket fence.

And between your mind and the world, it’s like a line painted on the sidewalk. Language and culture enter and pattern your mind from the moment of birth. Empathy and love naturally attune you to other people, so your mind moves into resonance with theirs. These flows of activity go both ways as you influence others.

Within your mind, there are hardly any lines at all. All its contents flow into each other, sensation becoming thoughts feelings desires actions and more sensations. This stream of consciousness correlates with a cascade of fleeting neural assemblies, each assembly dispersing into the next one, often in less than a second.