What we say has lasting consequences, but we're not giving a deposition when socializing. We have no mechanism to show how we've evolved over time on any curren

What we say has lasting consequences, but we're not giving a deposition when socializing. We have no mechanism to show how we've evolved over time on any currently contentious issue - a weak "that was a long time ago" doesn't tend to matter. The ability to forget what is no longer important is a trait that is crucial to our brain function, and it stands to reason that it is crucial for a society.