To the ancients, the existence of "zero" was incomprehensible.
Ancient China had concepts such as "emptiness" and "nothingness," but they were never linked to "zero." So-called "vacuum" did not mean there was absolutely nothing there; there were still many substances the human eye could not observe.
Yet you could feel that there was not a single coin left in your pocket, that there was no furniture at all in a house, making it look empty and bare. When you placed a chair in an empty room, that room was no longer quite so empty. A chair was unlike a drop of water or a grain of sand; one chair plus another chair made two chairs.
If water froze into ice blocks, and water mixed with sand became cement blocks, then one block of ice plus another block of ice made two blocks of ice, and one cement block plus another cement block made two cement blocks. There were certain rules behind this. It was like a jigsaw puzzle: it had clear boundaries. Two adjacent pieces needed not only matching edges, but matching patterns as well. Only when a puzzle piece's grooves followed the rules of connection and its pattern matched could two pieces be joined together.
When the puzzle was complete, people saw an intuitive image—for instance, the finished picture might be the Mona Lisa. If one followed only the rules of connecting the grooves while ignoring the rules of the image, the final result might be a pile of "garbled nonsense." And if one looked for puzzle pieces based solely on the image without seeking the rules within, it was like gambling on luck. Even if it was completed, no experience or knowledge would be formed. Why not begin a puzzle from the edges? What sort of groove edges