Everyone will say that [piety] is a major principle ... but why they do not study it is because it is so obvious and certain (Introduction to Path of the Just).
We take many things for granted. Is justice important? Of course! Is morality vital? Without a doubt! Are honesty and decency essential character traits? How can one even pose a question when the answer is so obvious?
In Path of the Just, a monumental work on ethics, Luzzato points out that some people exert a great deal of effort in order to try to gain greater understanding in various subjects, some of which are abstract and have little practical application, but they neglect investigating concepts which are important in everyday life. These people don't minimize the value of the latter; to the contrary, because these subjects are so important, everyone takes for granted that they understand them as well as they can figure two plus two equals four.
What is justice? What constitutes morality? What does it mean to be honest and decent? Who determines desirable values? To what degree is a particular trait commendable? In Luzzato's time, like today, these subjects were relegated to pundits in ivory towers who had nothing better to do than spend time analyzing and deliberating these "intangibles." People who were occupied in business, homemaking, labor, and professions had little time for such luxuries. Too many still think they don't.
Luzzato points out that unless we make a concerted effort to understand the values that we espouse, we may be grossly derelict without being aware of it.