What form does this επιστήμη (episteme - knowledge) take, and how far, in the various areas of human life and study, can our need for it be satisfied? What will the most satisfactory answers to our "why" questions be like? How are our various answers related? How far should we press the demand for understanding?
(The quote is from Martha Nussbaum on Aristotle's De Motu Animalium. The image is the rainbow serpent from aboriginal mythology.)