Farting is a universal human experience, as routine as eating, breathing and sleeping. And it seems to be a cross-cultural and trans-historical fact that passing gas, at least in most social contexts, is rude and offensive.

There’s also the fundamental truth pertaining to the topic: farts are funny. But why is this the case? They’re often a source of discomfort and embarrassment, so why do they double as an inspiration for humor, even literary beauty?

Literary giants let it rip

Every culture in recorded history has had its preferred forms of humor relating to bodily functions, but none have been more reliable in stirring a reaction than fart jokes. In fact, according to British academic and poet Paul MacDonald, the oldest joke in recorded history – which dates back to the Sumerians in 1900 BC – was a fart joke: “Something which has never occurred since time immemorial; a young woman did not fart in her husband’s lap.”

Fart jokes have also found their way into some of the classics of Western literature. One of the most well-known appears in Chaucer’s Canterbury Tales. In the Miller’s Tale, Nicholas and Absalom are vying for the same girl, and Nicholas decides to humiliate his rival. So he waits at the window for Absalom to beckon the girl. And just when he does, Nicholas’ rear protrudes to “let fly a fart with a noise as great as a clap of thunder, so that Absalom was almost overcome by the force of it.”

Even the great Bard of Avon himself, William Shakespeare, resorted to a flatulence pun in his play The Comedy of Errors, where Dromio of Ephesus declares, “A man may break a word with you, sir; and words are but wind; Ay, and break it in your face, so he break it not behind.”

Less surprisingly, the irreverent Mark Twain’s spoof entitled 1601 features the flatus. In this imagined conversation between Queen Elizabeth’s court and a few renowned writers, someone among the company passes gas: “In ye heat of ye talk it befel yt one did breake wind, yielding an exceding mightie and distresfull stink, whereat all did laugh full sore.”

The queen inquires as to the source, and one Lady Alice declares her innocence: “Nay, ‘tis not I yt have broughte forth this rich o'ermastering fog, this fragrant gloom, so pray you seeke ye further.”

Meanwhile, Jonathan Swift, the author of the classic Gulliver’s Travels, devoted an entire book to the subject with The Benefit of Farting Explained. (Swift published it under the pseudonym “Don Fartinando Puff-Indorst, Professor of Bumbast in the University of Crackow.”) The title page asserts that the essay was “translated into English at the Request and for the Use of the Lady Damp-Fart, of Her-fart-shire” by “Obadiah Fizzle, Groom of the Stool to the Princess of Arse-Mini in Sardinia.” And an opening poetic ode refers to the flatus as “Cure of cholick, cure of gripes, tuneful drone of lower pipes.”

Swift then goes on to subject the fart to a detailed analysis – carefully describing its legal, social and scientific dimensions – before concluding that there are multiple species of fart, including “the sonorous and full-toned or rousing fart,” “the double fart,” “the soft fizzing fart,” “the wet fart” and “the sullen wind-bound fart.”

The philosophy of fart jokes

Clearly, as these examples show, flatulence humor is timeless. But why are farts universally funny?

We might begin by asking what makes anything funny. Historically, there have been three major philosophical theories about laughter.

The superiority theory says that we laugh when we feel “sudden glory,” as Thomas Hobbes put it – a sudden sense of superiority over a person, especially someone to whom we ordinarily feel inferior. Cases of slapstick humor, such as the pie-in-the-face or someone slipping on a banana peel, fall into this category.

Kant and Schopenhauer argued on behalf of the incongruity theory, which says we laugh at the juxtaposition of things that don’t ordinarily go together, such as a talking dog or a bearded woman.

And relief theorists like Spencer and Freud maintain that laughter is how we relieve nervous tension regarding subjects or situations that are socially taboo or inappropriate. This explains the popular appeal of jokes based on sex, ethnicity and religion.

But must we regard these theories as mutually exclusive? I suspect they are compatible explanations for different contexts of humor.

Philosopher John Morreall defends a theory that invites such a view. Morreall proposes that the common core to anything that prompts laughter is a “pleasant psychological shift.” If we apply this theory to flatulence, it becomes clear why farts are universally funny. It’s because they are capable of producing this effect in all of the ways identified by the three theories of humor.

And events that satisfy the criteria for all three forms of humor tend to be especially funny. For example, a few years ago, a YouTube post was made of Fox News anchor Megyn Kelly passing gas repeatedly on a live broadcast (to date, this clip has nearly 12 million views).

Whether or not this actually happened, Kelly’s gaseous outburst certainly prompts a sudden sense of superiority in viewers, and it’s obviously incongruous with the formal context of a news broadcast. Moreover, the laughter this elicits (as it did even on the set of the broadcast) helps to relieve the nervous tension created by this social taboo.

But even where farts only satisfy one of the criteria for producing the “pleasant psychological shift” they are still humorous. And in most social contexts, they do at least this much.

This account of the universality of flatulence humor is, of course, a matter of debate. But one thing is beyond dispute: farts are funny. They always have been. And, it appears, they always will be.