Here is a question most people do not think to ask for the first forty years. Are you your own friend? Not do you like yourself, which is vague enough that anybody can answer it dishonestly without noticing. Something more practical than that. If you spoke to a friend the way you speak to yourself, how long would they stay?
Asked properly, the answer arrives immediately and is humiliating. Nobody would tolerate it. Nobody would stay a week and most would not stay an afternoon. The commentary that runs about oneself is harsher than anything anybody would say to a stranger they actively disliked, and it runs continuously, and it has never once been thought of as unkind because it has never been thought of as anything at all.
It is simply the weather in there. It has been the weather since we were very small, and weather is not something anybody evaluates. It is just what is happening, every day, in the place where we live.
Where the voice came from
It is worth asking whose voice it actually is, because it is very rarely original. Listen to the phrasing rather than the content. Very often it is somebody else's, absorbed early and kept perfectly intact ever since. A teacher, a parent, a relative, a group of other children on a particular afternoon.
Something was said once, or several times, at an age when nobody had any capacity to evaluate it, and it went straight in and stayed. The person who said it has almost certainly forgotten it entirely. They may well be dead. They certainly did not intend to install a permanent inhabitant who would still be on duty thirty years later using the same words.
Once whose voice it is can be heard, something shifts. Not because it stops, because it does not stop. Because it stops being the truth and becomes a quotation, and a quotation can be examined, and questioned, and eventually declined. The truth cannot be declined. That is the difference and it is a large one.
Why achievement does not satisfy it
The obvious response is to disprove it. Achieve enough and the voice will have to concede the point and fall silent. This is the engine underneath a very large number of successful lives, and it does not work, and it is worth understanding exactly why it cannot.
The voice is not making a claim about performance and it never was. If it were, evidence would settle it, and evidence has been arriving steadily for decades without settling anything at all. It is making a claim about the person, and no performance in the world can answer a claim about somebody's existence.
So each achievement is accepted briefly, examined, and then the standard adjusts and the commentary resumes at the new level within a fortnight. Everybody assumes this means they have not yet done enough and redoubles their efforts. It means the wrong question is being answered with tremendous discipline, and it will go on being answered until somebody notices.
Living with it
Almost nobody silences theirs and it is unwise to expect to. It has been there a whole life and will probably see everybody out, and an uneasy peace with that is the realistic outcome. What can change is smaller than silence and makes considerably more difference than anybody expects.
It gets noticed, which it was not before, because a thing that has always been there is not noticed at all until something disturbs it. It can be heard starting. And having heard it start, there is a small gap in which one question can be asked, which is whether this would be said to somebody cared about who had done exactly the same thing.
The answer is always no. The no does not stop the voice and hoping it will is a waste. What it does is stop the automatic agreeing, which turns out to be the part that was doing the damage all along. We have been in our own company every single day of our lives and will be until the last one. It seems worth knowing what that company has actually been like.