Why do some words related to the dead have the word "spirit"?

Ling (pinyin: líng) is a commonly used Chinese character [1], and the earliest glyph can be found in the inscription in the Spring and Autumn Period [2]. Spirit is a special name for dancing witch in Chu language, and it can also refer to god by extension. The ancients thought that people would become elves after death, so spirit also refers to things related to the dead, such as mourning halls. It can also refer to kindness, and by extension, it can refer to intelligence and understanding of things. There is also flexibility and dexterity, such as agility, cleverness and ingenuity.