What guarantees the correctness of knowledge?

"Because it was written in a book." There is no warranty.

Your experience is correct in the sense that it is an observation fact. However, the guarantee is lost when you interpreted it. (Note: I introduce the figure by Einstein in (1.7) Summary)

If we can do experiments, we can prove incorrectness. "If this my interpretation is correct, the result of experiments should be like this, but it was not."

In Chapter 1, I explain about the verification. You write a program based on your own interpretation and observing the execution result. You can verify your understanding. You can see when your interpretation is incorrect. However, you can not get a guarantee that it is correct. (*2)

(*2): Computer scientist Edsger Wybe Dijkstra said, "Program testing can be used to show the presence of bugs, but never to show their absence!"

Dijkstra (1970) "Notes On Structured Programming" (EWD249), Section 3 ("On The Reliability of Mechanisms"), corollary at the end.

So, what can we do in areas where we can not do experiments? One of the criteria that you can use in such a field is consistency with many things. The criteria is not a guarantee of the correctness, but it is useful criteria. Knowledge consistent with much other knowledge has a wide range of application.

For example, the knowledge that is consistent across books written by different authors is likely to be correct. When the knowledge written in the book matches well with your experience, you feel a sense of comprehension. Suppose you give a lecture. The audience is very pleased when what you talked fits well with the experience of the audience.

Fig: Knowledge in books should connect with your own experience

A: You read book, got some pieces of knowledge, but those are not connected.

B: Those are connected each other, but those are not connected outside the book.

C: Those are connected to your experiences and pieces in other books.

Many people read books and extract some sentences from books. Try a group organization of those pieces. It give you a good learning experience. There are cool sentences, which does not connect to the other pieces. On the contrary, you may realize that some sentences which are not flashy at all are actually very important knowledge that connects information of multiple books.

Reading a book, making pieces, and organizing groups. Through this verification activity, you can see whether the sentences you wrote out were consistent knowledge that was easy to connect with other things, or not. By repeating this activity, you can enhance your skill to find the knowledge that is likely to connect with many things.

What will happen if you collect knowledge that is likely to connect with many things and organize groups?

By creating a group and attaching a nameplate, you verbalize the reason why they are consistent. Repeating this activity increase the consistency of your knowledge. As a result, you can get a network of knowledge tightly connected. It is very useful.