The most famous of all Zhuangzi stories—“Zhuang Zhou Dreams of Being a Butterfly”—appears at the end of the second chapter, “On the Equality of Things”.
Zhuangzi (book) (Wikipedia)The Zhuangzi (Chinese: 莊子, historically romanized Chuang Tzŭ) is an ancient Chinese text from the late Warring States period (476–221 BC) containing stories and anecdotes that exemplify the carefree nature of the ideal Taoist sage. Named for its traditional author, “Master Zhuang” (Zhuangzi), the Zhuangzi is one of the two foundational texts of Taoism, along with the Tao Te Ching.
Dream argument (Wikipedia)The dream argument is the postulation that the act of dreaming provides preliminary evidence that the senses we trust to distinguish reality from illusion should not be fully trusted, and therefore, any state that is dependent on our senses should at the very least be carefully examined and rigorously tested to determine whether it is in fact reality.