只知道Popper講過白色的天鵝。這些三個世界都是後人幫他添蛇畫足的，我把網路的整理如下： Karl Popper's the Three Worlds of Knowledge "What is the object of knowledge?" asks young Grasshopper. "There is no object of knowledge," replies the old Shaman, "To know is to be able to operate adequately in an individual or cooperative situation." "So which is more important, to know or to do?" asks young Grasshopper. "All doing is knowing, and all knowing is doing," replies the Sage, and then continues, "Knowing is an effective action, that is, knowledge operate effectively in the domain of existence of all living creatures." (paraphrased from M..