“Let me not seem to have lived in vain,” the Danish astronomer Tycho Brahe whispered on his deathbed, not realizing that the astronomical tables he was leaving behind would become the portal through which Kepler arrives at the laws of planetary motion; not realizing that the measure of an unwasted life is not what outlives it but how it was lived — how much integrity and authenticity and creative vitality filled these numbered days, these unrepeatable hours.

Most of us will not leave behind a r...