Have you ever known that you knew something but you didn't know what you knew? Have you ever been unable to say something you know very well? Have you frozen in the middle of a task that you have always done with ease? Have you been frightened when a word you have used many times suddenly disappeared from your mind?

If your answer is yes, it means that you have also experienced presque vu.

Presque vu, which means "about to be seen" in French, is a phenomenon known colloquially as "on the tip of my tongue". Unlike forgetting, it is the state of not remembering what you know. When your friend asks you about something you know very well, you know that you know the answer, but you can't remember what it is. It creates a feeling that you are on the verge of a powerful realisation, insight. It gives the feeling that you are on a journey of discovery. And then there is a frustrating disappointment when you can't find the word. This is caused by the brain missing details about something it already knows.

In other words, it puts you in a state of not remembering what something you know how it is. For example, you know how an operation in mathematics is done, but you cannot remember the name of the operation. You tell your friend about a film you know very well, but you cannot remember the name. Presque vu is as common as deja vu and is completely normal. As long as your memory doesn't really start to fade visibly, there is nothing to worry about.

Have you ever experienced presque vu?