It is similar to becoming subjective, to focus on personal experiences and physical sensations. Let's consider the opposite. It is common to handle abstract concepts without concrete experience or physical sensation. Often you are using it without being aware that you are dealing with abstract concepts.

According to the physicist Richard Phillips Feynman, one person said that "the shoe sole decreases due to friction with the ground," and Feynman asked, " What is friction?" How would you answer?

If you can not answer, "friction" for you is such a rootless knowledge that you cut off branches of cherry blossoms. Words can be used as symbols without understanding their meaning. Whether you understand the meaning can be experimented by whether you can explain without using that word. For example, if you can answer "small bumps of ground scrape off the shoe sole," it shows the concept of "friction" in your mind is supported by a physical sensation. You **see** why the shoe sole decreases.

Knowledge and rootless knowledge

In abstract concepts, there may be many people who think of academic terms. However, from the viewpoint of whether it corresponds to a physical sensation, quite many cases are abstract concepts. For example, what is the "voice of birds"? Imagine that you hear the voice of birds. If possible, ask the other people the same question and compare how the answer differs from yourself.

Some people imagine the sparrow at dawn, and some imagine the crow a fall sunset. Some imagine the voice of the pet bird they own, and some imagine "cock-a-doodle-doo!!" on a rural farm.

Suppose now that you are developing software on a team and one of the members suggests to make a notification sound a voice of birds. Are you agreeable or not?

You do not know what kind of sound the abstract concept, the "voice of birds" expresses. You can not discuss productive about whether good or bad the "voice of birds" is. First of all, it is necessary to bring the abstract concept closer to the physical sensation they are listening concretely.

Bring it closer to "non-verbalized physical sensation / raw experience"

*18 This commentary is written in "What is science?" Richard Phillips Feynman, Translated by Masako Onuki / Yozawa Ezawa, "Finman's Best Essay", Iwanami Shoten, 2001

*19 In Chapter 1, I told a story that if you picked up the box at the top of the pyramid, you couldn't put it at the same height, and it falls to the ground.

*20 Mathematics is a discipline that deals with concepts that are far from physical sensations. So in this field, getting closer to the physical sensation is criticized for being a source of error. Instead, they make concrete examples that satisfy the theorem. Or rewrite parts of the theorem to find concrete counterexamples. The existence of counterexamples shows the part of the theorem necessary.