From a great article by Robert Burton about the feeling of certainty and belief:
To understand what I mean about the feeling of knowing, read the following paragraph at normal speed. Don't skim, give up halfway through or skip to the explanation. Because this experience can't be duplicated once you know the explanation, take a moment to ask yourself how you feel about the paragraph. After reading the clarifying word, reread the paragraph. As you do, pay close attention to the shifts in your mental state and your feeling about the paragraph:
A newspaper is better than a magazine. A seashore is a better place than the street. At first it is better to run than to walk. You may have to try several times. It takes some skill but it is easy to learn. Even young children can enjoy it. Once successful, complications are minimal. Birds seldom get too close. Rain, however, soaks in very fast. Too many people doing the same thing can also cause problems. One needs lots of room. If there are no complications it can be very peaceful. A rock will serve as an anchor. If things break loose from it, however, you will not get a second chance.
Is this paragraph comprehensible or meaningless? Feel your mind sort through potential explanations. Now watch what happens with the presentation of a single word: kite.
In an instant, you are flooded with the "aha" feeling that the paragraph makes sense. There's no time for deep consideration and evaluation. Before you can reread the paragraph, your unconscious mind has already sorted through various possibilities, determined that the sentences collectively fit the description of a kite and sent you notification.
(Pretty cool, found via Mind Hacks)