From the Thoreau blog:

“Some men make their due impression upon their generation, because a petty occasion is enough to call forth all their energies; but are there not others who would rise to much higher levels, whom the world …

Marcus Aurelius, Meditations:

“When an object presents itself to your perception, make a mental definition or at least an outline of it, so as to discern its essential character, to pierce beyond its separate attributes to a distinct view …