For many years I wrongly thought that the way to "know myself" was to engage in several hours a day of solitary meditation. Sure, I did learn some things about myself in this way and developed a lot of discipline by meditating every morning whether or not I felt like it.
Now, though, I've come to realize that it is easy to fool ourselves when the only conversation we're having is within our own mind -- I talking to me; us speaking to ourself; one part of our psyche conversing with another part.
As noted in my previous post about a book I'm reading, Stephen Fleming's Know Thyself: The Science of Self-Awareness, the outside environment provides important feedback about how well we're in touch with reality. For example, inside my own head I can fantasize that I'm in contact with higher realms of reality.
Out in the world, imagining that I'm in touch with something that isn't really there is much more difficult, because "there" is apparent to other people also.
In a chapter called "Learning to Learn," Fleming describes the benefits of explaining things to others and communicating our thoughts in writing or out loud.
This helps to explain why I enjoy writing so much. By getting what is inside my head out into the world, I not only learn more about what I really think, I gain the benefit of other people being able to provide feedback to me about those thoughts.
We can understand why teaching and advising others can be so useful for our own learning by considering how it helps us avoid metacognitive illusions.
When we are forced to explain things to others, there is less opportunity to be swayed by internal signals of fluency that might create unwarranted feelings of confidence in our knowledge. For instance, the "illusion of explanatory depth" refers to the common experience of thinking we know how things work (from simple gadgets to government policies), but, when we are asked to explain them to others, we are unable to do so.
Being forced to make our knowledge public ensures that misplaced confidence is exposed. For similar reasons, it is easier for us to recognize when someone else is talking nonsense than to recognize that same flaw in ourselves.
...External props and tools can also provide a new perspective on what we know. Rather than monitoring murky internal processes, many of which remain hidden from our awareness, getting words down on the page and speaking them out loud creates concrete targets for self-reflection.
...We naturally extend our minds onto the page, and the extensions can themselves be targets of metacognition, to be mused about and reflected upon just like regular thoughts and feelings.