Frankly, this is the most difficult topic for me to write about. This is something abstract, not easy to express or formulate in written or verbal form. But I tried to express it in this post. When I was in junior high school, I was told that knowledge consisted of two main branches, namely exact and non-exact knowledge, as I mentioned in a previous post . Simply, I refer to it as logical and illogical knowledge, the two inseparable abilities which actually united and embedded within humans as I mentioned in the other previous post . I think those two posts can stimulate our minds on how to understand Tacit knowledge. There are two main realms. The first realm refers to the science of mathematics, physics, chemistry, computer programming, etc., which can be coded/formulated, where the result is logically certain. The second realm refers to social sciences, politics, psychology, philosophy, art, etc., which cannot be coded/formulated with a definite formula. Lately I have heard the term