Enneads IV.8: Of the Descent of the Soul Into the Body
Heraclitus, the Originator of These Questions, Answers Them Obscurely
Heraclitus, who recommends this research, asserts that “there are necessary changes of contraries into each other;” he speaks of “ascenscions” and of a “descent,” says that it is “a rest to change, a fatigue to continue unremittingly in the same kinds of work, and to be overwrought.” He thus reduces us to conjectures because he does not explain himself definitely; and he would even force us to ask how he himself came to discover what he propounds.