Contradictions are an inseparable part of every human culture. In fact, they are culture’s engines, responsible for the creativity and dynamism of our species.
Consistency is the playground of dull minds.
Over the millennia, small, simple cultures gradually coalesce into bigger and more complex civilisations, so that the world contains fewer and fewer mega-cultures, each of which is bigger and more complex.
The best way to appreciate the general direction of history is to count the number of separate human worlds that coexisted at any given moment on planet earth. Today, we are used to thinking about the whole planet as a single unit, but for most of history, earth was in fact an entire galaxy of isolated human worlds.