We understand a culture the best where the culture's members hold contradictory beliefs and reconcile incompatible values.
In contrast to physics, which is (almost always) free of inconsistencies, cultures are constantly trying to reconcile contradictions among themselves.
Take the nobility in medieval Europe as an example. A typical nobleman believed in both Christianity and chivalry. He went to church to learn he must rise above those dangerous temptations such as riches, lust, and honor. He has to avoid violence and extravagance. If attacked, he needs to turn the other cheek.
Regardless of this meek and reflective mood, the nobleman then went to his lord's castle, where wine flowed like water and guests exchanged dirty jokes and bloody war tales. The barons taught him that "It is better to die than live with shame. Only blood can wipe out the insult if someone questions your honor."
This contradiction stands not only between Christianity and chivalry in medieval Europe. In modern society, most people see social equality and individual freedom as fundamental values. Yet the two values contradict each other. While we can ensure equality only by curtailing the freedoms of those who are better off, guaranteeing that every individual will be free to do as they wish inevitably short-changes equality.
It's an essential feature that any culture's member must be able to hold contradictory beliefs and incompatible values. These tensions, conflicts, and irresolvable dilemmas are the spice of every culture. That's why Harari said that if a Christian wants to understand the Muslims, "they shouldn't look for a pristine set of values that every Muslim holds. Instead, he should enquire into the catch-22s of Muslim culture, those places where rules are at war and standards scuffle. It's at the very spot where the Muslims teeter between two imperatives that you'll understand them best."
This also reminds me of what is mentioned in Why I do what I do: Values are revealed through real-life trade-offs.