Ambition is disfigured into arrogance when it becomes unmoored from self-awareness, from a realistic assessment of one's competences. - Maria Popova

A quarter millennium later, Emily Dickinson would write in a poem the central metaphor of which draws on Kepler’s legacy:

Each that we lose takes part of us;
A crescent still abides,
Which like the moon, some turbid night,
Is summoned by the tides.

It takes rare courage to recognize that feelings are the most perishable of our possessions, even more so than opinions, for an opinion — that is, a real opinion, which is qualitatively different than a fleeting impression or a borrowed stance — is arrived at via a well-reasoned argument with oneself. Not so a feeling — feelings coalesce out of the vapors that escape from the deepest groundwaters of our unreasoned and unreasonable being, and whatever rainbows they may scatter for a moment when touched with the light of another, they diffuse and evaporate just as readily, just as mysteriously.
Love, Margaret implies in her letter to Sam, is never to be taken for granted — it is to be met moment by moment, on its ever-changing terms.

There is no overstating the triumph of having remained motivated by beauty in taking down the ugliest malignancies of human nature’s grasp for power.