Knowing what you don't Know

How do we claim "What we know" ? Knowing - Is it something that we have heard of ? Or Is it something which we have read about and almost forgotten it so I have just a little (almost no idea) idea about that? Or is it something which we know almost everything about? 

Most of the time what we actually know is a fraction of our perceived notion of "knowing". This is described as illusion of explanatory depth.

So what happens is we generally form a circle around things and claim that we "know" it. This prevents us from actually knowing it and let us remain in that "complacency" that we know it. So what I have learnt over a period of time is "admit frankly what you don't know", it will help you extend your knowledge. 

Next time when someone brings up some topic which you claim to know but actually don't know then make a entry in your learning diary about that word. When you reach home/office, search it on web or talk to people and try to gain knowledge about it. Engaging in social learning also helps expand our knowledge. It requires more knowledge to explain someone something and instruct them. So when you think you have understood something well then try to explain that to someone. Also when someone asks you counter question that is when your real "knowing" gets evaluated. Explaining something to someone is such a satisfactory feeling.