Who breaks a butterfly upon a wheel?

The line "Who breaks a butterfly upon a wheel?" forms line 308 of the "Epistle to Dr Arbuthnot" in which Alexander Pope responded to his physician's word of caution about making satirical attacks on powerful people by sending him a selection of such attacks. It appears in a section on the courtier John Hervey, 2nd Baron Hervey, who was close to Queen Caroline and was one of Pope's bitterest enemies. The section opens as follows:[3]

Let Sporus tremble –"What? that thing of silk,
Sporus, that mere white curd of ass's milk?
Satire or sense, alas! can Sporus feel?
Who breaks a butterfly upon a wheel?
Yet let me flap this bug with gilded wings,
This painted child of dirt that stinks and stings;
Whose buzz the witty and the fair annoys,
Yet wit ne'er tastes, and beauty ne'er enjoys,

"Sporus", a male slave favoured by Emperor Nero,[3] was, according to Suetonius, castrated by the emperor, and subsequently married.[4] Pope here refers to accusations made in Pulteney's Proper reply to a late scurrilous libel of 1731 which led to Hervey challenging Pulteney to a duel. Hervey's decade-long clandestine affair with Stephen Fox would eventually contribute to his downfall.[5][6] As first published the verse referred to Paris, but was changed to Sporus when republished a few months later.[7]

"What? that thing of silk" uses a metaphor of a silkworm spinning that Pope had already used in The Dunciad to refer to bad poets. "Ass's milk" was at that time a common tonic, and was part of a diet adopted by Hervey. "This painted child" comments on make-up such as rouge used by the handsome Hervey.[3]

Another graphic instance of the usage can be found in An Introduction to Harmony by William Shield (1800), wherein he writes: "Having brought this Introduction to Harmony before that awful Tribunal, the Public, without first submitting it to the inspection of a judicious friend, I shall doubtless merit severe correction from the Critic; but as my attempt has been rather to write a useful Book, than a learned Work, I trust that he will not break a Butterfly upon the wheel for not being able to soar with the wings of an Eagle."[8]

William Rees-Mogg, as editor of The Times newspaper, used the "on a wheel" version of the quotation as the heading (set in capital letters) for an editorial on 1 July 1967 about the "Redlands" court case, which had resulted in prison sentences for Rolling Stones members Keith Richards and Mick Jagger.[9]

The philosopher Mary Midgley used a variation on the phrase in an article in the journal Philosophy written to counter a review praising The Selfish Gene by Richard Dawkins, where she cuttingly said that she had "not attended to Dawkins, thinking it unnecessary to break a butterfly upon a wheel."[10]

The British rock band The Mission enjoyed a no. 12 hit in the UK Top 40 (no. 1 in South Africa) in January 1990 with a song entitled "Butterfly on a Wheel".[11]

The British rock band The Cult ask the question, "Who Would Break A Butterfly on a Wheel?" in their song "Soul Asylum" off the 1989 Album, Sonic Temple.

A film titled Butterfly on a Wheel was released in 2007. In the US the title of the movie was changed to Shattered.[12]

The British rock band Coldplay used the lyric “The wheel breaks the butterfly” in the 2011 song ‘Paradise’.[13]

The British rock band Oasis used the lyric “Catch the wheel that breaks the butterfly” in the 2008 song ‘Falling Down’.[14]

'Break a Butterfly on a Wheel' is the penultimate track on Similarities, a compilation album by Scottish rock trio Biffy Clyro.[15]