The hidden assumptions will get you every time

There is a valuable lesson for all of us here: Very often the most important assumptions we make are ones we are not even aware of making. This is one of the reasons why the study of the history of philosophy is valuable. By its study, we can come to see that things that seemed utterly obvious to people in one era seem dubious to those in another era. And we can perhaps sometimes, by comparing our contemporary intellectual world to those past worlds, become aware of assumptions we have that we would otherwise fail to see.—Evans, A History of Western Philosophy, 252