There is a moment, that instant when you must choose to do or not to do. Instinct makes you aware of its importance: Act now, and everything hereafter is different. Act not, and things remain the same.
In her History of Ancient Sculpture (1883), Lucy M. Mitchell describes a Greek deity, long out of fashion, represented in sculpture by Lysippos, who worked in fourth-century-BC Peloponnese:
“Cairos was to the people of Lysippos’ day … an actual god, believed to influence men at critical moments, when sudden decision was required, and leading them to the proper improvement of every fleeting opportunity” (511).