Work is the only thing that gives substance to life.

Meaning, on this view, comes from effort that is directed at something, not from comfort, entertainment or possessions. Work here doesn't have to mean a paid job. It means absorbed, purposeful activity in which we use our abilities on a problem or a craft that matters to us. Life feels thin when it is only consumed and fills out when we make or improve something.

The idea fits the long tradition, running back to Aristotle, that flourishing lies in activity rather than idle pleasure. It also suits Einstein's own life, which was shaped by a deep devotion to understanding physics. A caution is in order, though: the attribution is doubtful, since I know of no solid source placing these exact words with him, so it is best read as a sentiment in his spirit.

Today, someone who feels adrift after a dull day job, or after retiring, might take on a project that asks something of them. They could restore an old bicycle, tend a community garden or teach a neighbor's child to read. The task matters less than the steady, committed attention, which tends to give days a shape and a sense of weight.