The rhetorical question is a hollow-sounding device, much favoured by monologuising dons: asked for the sake of effect, it doesn't feel obliged to provide an answer. Stefan Collini addresses the empty air in his title but then loses his nerve in the first paragraph of his book, which gives in to qualms about that interrogatory preposition. Is to ask what universities are for the same as asking what love or a country is for? "Any answer," Collini sighs, "is bound to be a tiresome combination of banality and tendentiousness." Further questions proliferate, "spiralling down into an endless regress".

Can this be his reply to the titular question? What universities are for, we gather, is to house the talking heads who pace round in circles as they play linguistic games. Many pages pass before Collini, now cordoning off the suspect preposition inside quote marks by "asking what universities are 'for'", confesses that he isn't even sure what a university is, though he decides that  in a world where the name applies to former polytechnics, hairdressing academies, and mail-order firms that will sell you a PhD for a few pounds  we had better not "be insistently purist about the usage of the term 'university'". At least, unlike Bill Clinton extricating himself from charges of sexual hanky-panky by mobilising the skills he learned at Yale Law School, Collini refrains from asking "what the meaning of 'is' is".

He is a little clearer about what universities are not. Officially at least, they no longer function as social clubs for the sons of the landed gentry, or as seminaries to train Anglican priests; after "the Thatcher government's Kulturkampf against universities"  Collini's German term for cultural war is probably accompanied by a self-admiring little smirk  they are required to operate like business organisations, although Collini, who jeers at the notion of HiEdBizUK, thinks that they're not that either. A long chapter about Cardinal Newman's notion that universities exist to "raise the intellectual tone of society" also ends by deciding that Newman is no help.

The fog momentarily clears when Collini calls the contemporary university "a marriage of convenience between a type of school and a type of research laboratory", but this too is dismissed as "the most frequent, because the most plausible, misconception" about the matter. Plausibility, in the heady realm of academic discourse, is enough to make a thesis untenable. Trying to follow Collini's contortions, I was reminded of a remark made by a former Oxford colleague of mine during a discussion of some newfangled theoretical addition to the syllabus. "You just invent some problems," he shrugged, "and then you've got a subject." Or, in Collini's case, a book to add to the bibliometrical index on his CV.

Another attempt at a definition  disqualified in advance as "neat, but therefore only partly adequate"  says that "schoolchildren are taught, university students study". (In my recollection, the latter also bunk off, drink, dance, act, play sports, have sex, get the flu with astonishing frequency, pee on war memorials and sometimes toss the odd fire extinguisher off the top of a public building.) And how do dons occupy themselves while the students are purportedly studying? "What they, we, are doing most of the time," says Collini, "is worrying." Not having done much of this during my 38-year academic career, I felt curious about the source of Collini's gnawing anxiety. Eventually he lets slip a diagnosis of his condition: he and his kind are "prone to waking up too early in the morning worrying about the paragraph they wrote yesterday". Ah, the onerous workload of the intellectual: yesterday's output was one whole paragraph!

Collini groans about the "upper-body workout" he gets from lugging around the agenda papers for a Cambridge meeting, and expects commiseration when he complains about spending Saturday morning in the office writing references. Yet my erstwhile Oxford colleagues eagerly volunteered for administrative chores, which brought with them the bonus  locally known as a "buy-out"  of dispensation from teaching. You earn promotion by this kind of busybodying; if you do enough favours for others, you can be rewarded with "research leave", which will enable you to write a ponderously footnoted article on a subject of interest only to your fellow obsessives.

Preoccupied by worry, Collini doesn't mention the joy of discussing novels and poems with those he teaches. Perhaps the problem is the so-called "crisis in the humanities", which has dehumanised the study of literature by reducing authors to producers of texts and reducing those texts to position papers with agendas that interest us only if they contribute to contemporary debates about gender, sexuality and ethnic difference. And since Collini is free to write, why doesn't he enjoy that? No, the daily paragraph is meant to be forced out with the costive pangs suffered by those whose internal plumbing is stodgy.

Things brighten up in the second part of his book, when polemics replace the academic filibustering, though most of this section has been previously published, some of it more than a decade ago when the circumstances about which it protests were different.

At one point Collini risks another rhetorical question. As he trudges around the quad, he wonders "what happened to youthful dreams of intellectual excitement and literary glory". Since he gives no answer, let me do so for him. Youth passes, but if excitement expires it's your own fault. As for literary glory, it's not acquired by afternoons spent at "a meeting of the Cambridge University Press syndicate" or trips to London "to chair a meeting of the Modern Literature section of the British Academy". What universities are emphatically not for is to subsidise the self-pity of those they employ.