To catch the wind and shadows
To act or speak based on unfounded evidence or rumors
Negative
他指责媒体捕风捉影，蓄意制造麻烦 | Tā zhǐzé méitǐ bǔfēngzhuōyǐng, xùyì zhìzào máfan
He accused the media of reporting groundless information and deliberately causing trouble
[Source]
有些人会发现我们的批评是令人沮丧的，但我们也并非捕风捉影 | Yǒu xiē rén huì fāxiàn wǒmen de pīpíng shì lìng rén jǔsàng de, dàn wǒmen yě bìngfēi bǔfēngzhuōyǐng
Some may find our criticisms upsetting, but we do not make them without basis
[Source]
None
捉影捕风 (zhūo yǐng bǔ fēng)
In the story, the emperor takes the help of a 方土 (fàng shì). I've translated this as "supernatural shaman," and some dictionaries translate this as "alchemist" or "necromancer." None of these are exactly right. The 现代汉语规范词典 and the 汉语大词典 (pinyin in citations section) say that a 方士 practiced medicine, but also prophecy and astronomy. The 汉语大词典 also adds that a 方士 could speak with celestial beings and make immortality pills
《汉书》(Hàn Shū), a work documenting the history of the Western Han dynasty (西汉, Xī Hàn, 206 BC - 8 AD). It was written by 班固 (Bān Gù), and is generally known in English as the "Book of Han" or the "History of the Former Han."
Under construction
The Han Dynasty emperor 汉成帝 (Hàn Chéng Dì, 51 BC - 7 BC) was still childless despite being over forty years old. Many people spoke to the emperor about immortality and making sacrifices to supernatural beings as a cure for his condition, and they were rewarded with positions of power within the government. Eventually, the emperor started taking advice from a supernatural shaman (方土, fàng shì) and began frequently holding expensive sacrifices, but despite this, his fertility issues were not resolved.
In response to all of this, an official 光禄大夫 (guāng lù dàifu) named 谷永 (Gǔ Yǒng) wrote a formal letter (上书, shàng shū) to the emperor. The letter stated that while others' words were appealing, there was no such thing as a celestial being or an immortality pill, and that trying to find either would be as unachievable as catching the wind and shadows. He then provided several historical examples where former Chinese rulers had met disaster when trying to depend upon sacrifices or immortal beings, and he indicated that efforts to find immortals or spirits had never successful in ancient times or in modern ones.
Upon receiving the letter, 汉成帝 realized the error of his ways.