What do you call the rhetoric strategy of purposely writing a paragraph that no one can understand?

Solution 1:

An academic or pseudo-intellectual who uses convoluted phrases in order to intimidate the lay person, ostentate his or her position, and possibly, disguise the fact that they have nothing of any importance to say, is commonly called a windbag.

If you are looking for a fancier term for verbosity, I present pressologia

Perissology means using more words than necessary to explain one’s meaning, a pleonasm. Since perissology is three letters longer than pleonasm but means the same, you may argue it’s an example of the related habit of using long words when shorter ones will do.

In A Dictionary of Literary Devices: Gradus, A-Z by Bernard Marie Dupriez, we learn that it is indeed a tactic, a form of strategy for filling an empty page or moments of silence. However, as I understand it, it needn't be incomprehensible.

pressology is one of the principle devices used by the media in their production of filler or padding

A similar rhetorical device is battology, which Richard Nordquist defines as "A rhetorical term for needless and tiresome repetition in speaking or writing". It reminds me of the Italian verb battere and gerund form battendo, which can be translated to hammering, and the English idiom to beat around the bush when someone is deliberately being evasive or unclear.

But the best word I found, and one which didn't have me scrambling for my dictionary, is the pejorative and informal term academese.

Academese is characteristic of academicians who are writing for a highly specialized but limited audience, or who have a limited grasp of how to make their arguments clearly and specifically" (Garner's Modern American Usage, 2009).

A further example of academese is provided here, the words which I have placed in bold are the academese expressions.

Vernacular Equivalents to Academese

"[E]ffective academic writing tends to be bilingual (or 'diglossial'), making its point in Academese and then making it again in the vernacular, a repetition that, interestingly, alters the meaning. Here is an example of such bilingualism from a review of a book on evolutionary biology by a professor of ecology and evolution, Jerry A. Coyne. Coyne is explaining the theory that males are biologically wired to compete for females. Coyne makes his point both in Academese, which I italicize, and in the vernacular, staging a dialogue in the text between the writer's (and the reader's) academic self and his 'lay' self: 'It is this internecine male competitiveness that is assumed to have driven not only the evolution of increased male body size (on average, bigger is better in a physical contest), but also of hormonally mediated male aggression (there is no use being the biggest guy on the block if you are a wallflower).'

^{source: Gerald Graff, Clueless in Academe: How Schooling Obscures the Life of the Mind. Yale Univ. Press, 2003}

Solution 2:

Obfuscation:

To make so confused or opaque as to be difficult to perceive or understand: A great effort was made... to obscure or obfuscate the truth - Robert Conquest.
To render indistinct or dim; darken; the process of darkening or obscuring so as to hinder ready analysis.

Is it a literary device? I can't find it listed as such. Is it a rhetorical device? Absolutely. It is practiced by politicians and academics, and criticized by sharp minds like Mark Twain and George Orwell.

Solution 3:

It might be useful to examine Wikipedia's article on the subject of a book where the quote also appeared:

Fashionable Nonsense

The Wikipedia article in itself is delightful. It cites one philosopher, Bruce Fink, who was incensed by the book and claimed that the authors are 'demanding that "serious writing" do nothing other than "convey clear meanings".' Which made me roll around the floor, laughing, concerning the very idea of serious writing conveying obfuscation as its product!

You can't make this stuff up. Or rather, you can, and the very pretentious pseudo-intellectuals among us will get all huffy about the idea of conveying clear meanings.

Solution 4:

I would suggest academic obscurantism, a phrase in current use that perfectly describes this phenomenon, especially since the rise of postmodernism. Obscurantism was originally coined in 18th century Germany to criticize opponents of the Enlightenment, but its meaning has expanded to include

a style (as in literature or art) characterized by deliberate vagueness or abstruseness

an act or instance of obscurantism

Thus Ardath Mayhar admonishes his fellow writers in Through the Stone Wall: Lessons After Thirty Years of Writing:

Writing is for people, not for those who practice artistic one-upmanship or academic obscurantism. Any mode undecipherable to anyone except a professor of creative writing or another avant-garde writer is going to die soon and completely.