What Robert plant mean by does anybody remember laughter?

In the song "Kashmir," Robert Plant uses the phrase "does anybody remember laughter" to question whether anyone still recalls a time when laughter was the norm. The song speaks to a sense of nostalgia and longing, as it reminisces about a time past. This phrase is a central focus of the lyrics and conveys the idea that the carefree and jovial moments people once experienced have become a distant memory in a chaotic world.