Every now and then the “check oil” light on your car’s dashboard turns red… so you add a quart of 10w-40 and go on your merry way… or your grumpy way… or whatever way you were going.
Some time later, the light lights, you toss in another quart (unless you’re driving in Europe, where you would add a liter, which, thanks to Schoolhouse Rock, I know is a little more than a quart).
Then, one day, you go to the shop for them to, oh, whatever mechanics do at the shop — calibrate the servo-trans-turbo-anti-locking-carburator thingy or something (it doesn’t matter WHY you’re at the shop; that’s not the important part of the story) — and the mechanic says, “Hey, I just noticed that this oil light of yours is broken. It’ll just go off at any old time for no reason.”
What would that knowledge to do you?
Your car was broken, but you had no external indication of the problem. Would it even occur to you that the oil light was faulty? Of course not.
This, by the way is a more tame version of the thought-experiment … the more National Enquirer version is: What if you just found out that your “mother” is really your grandmother and your “sister” is actually your bio-mom? (And let’s add that as you scan your history, there is NO INDICATION at all that this was the case.)
Does this change your thoughts about who you are?
Regardless of your answer, consider this:
What if your most fundamental decision-making mechanism was broken and you didn’t know it?
Not that you were unable to make decisions, nor that every decision you made led to some unpleasant circumstance. But what if, say, it had a short-circuit so that any time you were deliberating or trying to decide between some options the “YES” signal went off totally randomly, having nothing to do with any sort of rational thinking process, and you just went with that YES, because you had no reason to think it wasn’t the result of a faulty YES-meter?
And what if, I’ll say this again to highlight it, you had no objective indication that this was happening? Sometimes the YES worked out well; other times not so well.
Would you be able to tell that your YES-meter was broken?
Nope.
And this problem is bigger than your car issue, because if you wanted to examine your decision-making mechanism, guess what? The only tool you have is the broken decision-making mechanism. So, if you start looking at the “data,” and played with theories about whether it was working or not, you could get a big random YES that “confirms” a theory that’s completely not true.
That is, you can’t use your damaged analysis tool to determine if you have a damaged analysis tool.
What difference, if any, would you expect to experience in your life if it turned out that, all along, ever since you were born, your decision-making analysis tool were broken and you just found out?
You can probably guess why I’m suggesting this line of thinking.
It could be true (though, again, if it is, it would be almost impossible to determine!)
Wrap your brain around that for a bit and let me know what you find… or take a gander at On Being Certain: Believing You Are Right Even When You’re Not by Robert Burton, and let’s chat 
