《淮南子·兵略训》
因为 无形 ，所以也就难以制迫它，也难以度量它，更不能用智巧来欺诈它，也无法来规划谋算它。
无形，则不可制迫也，不可度量也，不可巧诈也，不可规虑也。
Because it is intangible, it is difficult to force it or measure it, and it is impossible to deceive it with ingenuity or plan for it.