David Hume, a Scottish philosopher in the 18th century, is famous for skepticism on the objectivity of causality and validity of moral judgment. But his assertion that causes and effects, "is" and "ought" are distinct and the connections between them are uncertain because of their subjectivity puts the cart before the horse. The fact is that, as the subject encounter uncertain affairs, it must divide them into causes and effects or "is" and "ought" so as to reduce uncertainty.
Philosophy began in ancient Greece by inquiring what arche, namely the origin of everything is. Systemics as philosophy must also answer the question. The conclusion of our systemics is arche of the world and philosophy is uncertainty. The assertions made by the previous philosophers that arche is this or that element or the subject as substratum have come from forgetting the original arche. The uncertainty precedes everything historically and theoretically.