Is seeking an explanation for life’s deepest mysteries a worthy pursuit? Many scientists and theologians would say yes. Zen Buddhists practising in China from the 9th to 13th centuries CE, however, believed that it was important to embrace uncertainty instead of always seeking answers. For these monks, achieving enlightenment meant resisting the urge to know the seemingly unknowable. To foster this way of thinking, they meditated on paradoxical riddles called kōans to raise doubts about the very meaning of knowing and, through this, find deeper truths about existence. This playful animation from TED-Ed provides a brief history of kōans, and offers two rich examples from the roughly 1,700 kōans written to illustrate the key role of ambiguity on the path to enlightenment.