Su Weidao served several times as chief minister under Empress Wu Zetian. According to the Tang histories, he once said: “In handling affairs, one should not decide clearly. If there is an error, blame is sure to follow. It is enough to feel the edges and hold on to both ends.”
People called him “Su Moleng,” Su Who Feels the Edges. His words are the origin of the idiom 模棱两可, “feeling the edges, either way will do.” Dictionaries define it as taking no clear position.