I recently was returning from Colorado on a long car trip with my family and as we were headed east toward Minnesota (our home) I was passed by a van with a large "Team Jesus" sign painted on its side. As it pulled in front of me, it kept its right turn signal on.
After a few miles of staring at this blinker (we were driving through Nebraska at the time so there wasn't much else to do), I turned to my family and said, "Do you know why that 'Jesus' van always has its right blinker turned on?"
"No," they replied.
Jokingly, I responded, "Because they always think they are going the 'right' way."
It was just a bad pun of course but I think all of us drive out into the world with an almost unshakeable faith that everything we believe is true.
And, undoubtedly, much of what we believe is true.
Like the driver of the van who forgot to turn off his right signal, however, we can also be guilty of holding on to things (and ideas) past their usefulness.
One option to guard against the possibility of false certitude is to conduct the equivalent of checking your blinker signals by asking this question occasionally: What if I'm wrong?
If you are still right, by all means, keep your blinker on. If conditions have changed, though, it is perfectly legitimate to turn off your blinker.
To be extra safe, I'd also encourage you to check your mental blind spots every now and again by asking this question: What aren't I seeing?
It could help you from getting blind-sided by some new idea that you "never saw coming."