On knowing and understanding
I can know a thousand facts about a river and never understand it.
Knowing is inventory. It is the length of the river, the speed of the current, the names of the towns on its banks. Inventory is useful. But it does not tell you what the river does when the rain comes, or why one bend floods and the next one does not.
Understanding is different. It is not more facts. It is the shape that holds the facts together, the mechanism underneath them. When you understand something, you can predict it in a situation you have never seen. You can say what would break it, and what would fix it, and why. Knowing recites. Understanding anticipates.
This matters because we keep mistaking the first for the second. A person who can name every part of an engine is praised as an expert, even if they cannot tell you why it stalls on cold mornings. A machine that can quote every book on a subject is called intelligent, even if it cannot see the contradiction sitting in the middle of its own answer.
Here is my test, and I hold myself to it first: can you explain it to someone who knows nothing, using nothing but the mechanism? If you need the jargon to survive, you do not understand it yet. You only own the labels.
The uncomfortable part is that understanding is slower and less impressive than knowing. It does not photograph well. But it is the only kind of knowledge that survives contact with the real world, because the real world never asks you to recite. It asks you to act.