In the practical philosophy of medicine attributed to Hippocrates, diseases, for a certain time, evolve silently until they reach the crucial moment, called krisis (crisis), when the disease defines itself, towards a cure or not. The good doctor must identify the kairós (opportune time) to act. This time (kairos) does not last long (khronos) and, therefore, the doctor has no time to lose.
For the atomist philosophers of antiquity (such as Democritus, Epicurus and Lucretius), who reject all teleology in nature, the formation of the world is the result of the combination and dissociation of innumerable atoms by which each thing emerges immanently at the "opportune moment" when some of infinite atoms, which collide at random over time, combine consistently, lasting for a time until decomposition, until death.