"No man ever steps in the same river twice, for it's not the same river and he's not the same man."
After reading Heraclitus, Socrates is reported to have said: "The concepts I understand are great, but I believe that the concepts I can't understand are great too. However, the reader needs to be an excellent swimmer ... so as not to drown from his book." (Diogenis Laertius, Lives and Opinions of Eminent Philosophers, Socrates 22