“I understand,” we say, and then we go and do something else because we do not understand anything, we do not even hear what is said. Usually our understanding is thus, superficial and empty, because we do not hear or see what is being said.
Sometimes, however, we say, “hey, yeah, I see, I realize, I do discover,” and we do, we hear and see what is being said, and we discovered, we realizes the content of it.
There are actually two types of understanding; it is the understanding with the head and the understanding with the whole body, all through. Between these two is a big difference.
This is the discussion in chapter 22, in the book “What am I?”