《吕氏春秋·纪·仲夏纪》
有谁能够懂得在不见中包含这见，在不闻中包含着闻，在无形中包含着形，那他就差不多懂得道了。
有知不见之见、不闻之闻、无状之状者，则几於知之矣。
Who can understand that within non-vision lies vision, within non-hearing lies hearing, within non-form lies form, and thereby come to roughly understand the Way?