I just know. Isn't it the same for you?
I think the one thing that all humans are really good at is lying to ourselves. We tell ourselves that we are right, this won't have a negative effect on my life or the lives of those close to me, and that things will work out. When we are wrong we lie to ourselves to justify our "wrong" actions.
What happens, then, over the course of many years, is that we condition ourselves to either kill our conscience or master allowing it to live but successfully winning every battle of when it says we are in the wrong.
Being wrong can be something serious, or just having the wrong facts in an argument or debate. In the case of the later, I know when I am wrong in my head before my conscience says so. In this case I will try to correct myself before my opponent (if such a term is acceptable) does. This will also improve my standing among peers, colleagues, and the competition.
Correcting ourselves takes much more effort, but in the long run the pay out is much greater.