 This feature of Zhuangzi’s skepticism lies at the heart of the famous debate between Zhuangzi and Hui Shi about the fish-pleasure in which Zhuangzi defends a claim to know against Hui Shi’s challenge. Zhuangzi makes an assertion and Hui Shi initiates the skeptical challenge. His challenge implies that there is a favored or correct standard of knowing that turns out to be impossibly strict. All knowledge must come from inside. It’s impossibly strict because it doesn’t allow Hui Shi to issue the challenge in this conversation. 