Thinking about knowledge in the real world.

There are things that you know, many of which are actually true.

There are things that you know to be false, some of which are actually true.

There are things you think are probably true (or false), and are willing to estimate that probability. Those estimates are almost always biased. People almost always overestimate the accuracy of their predictions.

There are things you think are probably true (or false), but are unwilling to estimate that probability. Some of those things may be true (or false).

There are things you don't know whether they are true or not. Your are probably accurate about your ignorance in these cases.

There are things you think you ought to find our more about. Some of them, but not all, are indeed things you should find out more about.

There are things you think you know enough about. Many of them you should find out more about.

There are things you should know about, but are unaware that you should know about them.