What does the Gonzo fist Hunter S. Thompson used as a symbol represent? Why does it have two thumbs, etc.?

The Gonzo Fist, a two-thumbed symbol attributed to Hunter S. Thompson originally used as the slogan for his 1970 campaign for sheriff of Aspen, contains within the image a peyote on, the bud of a cactus plant that has hallucinogenic properties when ingested.