...is that the concept of change is the most stringent rule of history. When a certain worldview or mindset is at its dominant heyday, or at the peak of its entrenchment in the cultural zietgiest, it easily creates the idea in the mind of the vast majority that it's nigh-impossible to ever change. That was once true of chattel slavery, as it was a heavily entrenched institution in the early decades of America, so much so that a mere six years before the Civil War ended it for good, no less a personage than Ralph Waldo Emerson remarked, "No man living today will ever see the end of slavery."

This is something we all need to keep in mind, especially if we believe that any type of view or institution is so entrenched that it will prove an exception to the above rule of history.