折疑論 2.72

2.72

仲尼學老聃（家語適周篇。問禮於老聃。訪樂於萇弘。孔子將行。與南宮敬叔曰。吾師老聃。博古知今者也）。

Zhongni learned from Lao Dan. (The "Going to Zhou" chapter of the School Sayings states that he inquired about rites from Lao Dan and sought music from Chang Hong. When Confucius was about to set out, he said to Nangong Jingshu: "My teacher Lao Dan is one who is widely versed in the ancient and knows the present.")