We talk about tainted money, but is cash ever stain-free?

At the height of last month's phone-hacking scandal, someone tweeted: "I wonder what it feels like to be the current 'Rupert Murdoch professor of language and communication' in the Oxford English faculty right now." There are not many questions on which I can claim without immodesty to be the world's leading authority: indeed, this may be the only one. Unfortunately for me, though, the person who asked it almost certainly wasn't interested in the answer. Rather he or she was gloating: "I bet it feels terrible, and if it does, that's as it should be."

Just in case I'm not feeling the requisite degree of shame unprompted, commentators in those parts of the press Murdoch doesn't own have been busy taking potshots, too.

The Independent's Matthew Norman suggested renaming my position "the Rupert Murdoch chair of obfuscatory language and intercepted communications". A letter in Times Higher Education compared it to "the Medellin cartel chair of pharmacology, the Hugh Hefner chair of women's studies and the Robert Mugabe chair of applied electoral politics". On Twitter, someone else proposed "the Harold Shipman chair of medical ethics". The Daily Mail's Ephraim Hardcastle attacked not only the chair but also the academic work of the person who held it before me - a gratuitous piece of nastiness that I won't dignify here by repeating.

These writers don't know anything about me or my predecessor: their real target is clearly Murdoch. But in their eagerness to get at him, they are describing the Murdoch chair in ways that are meant to undermine its credibility as a serious academic position; and it's difficult to do that without also undermining the credibility and impugning the motives of the academics who have held it. Remind me, wasn't this casual disregard for people's feelings and reputations exactly what these righteous critics professed to find so loathsome about Murdoch's tabloids?

This personal stuff is also a problem because it distracts us from the fundamental issue: not just what we think of donor X, Y or Z (although of course that is a legitimate question), but also what role we think private and corporate wealth should play in our public university system. The current government evidently intends that it should play a much larger role in future. But the problems and risks entailed by that are considerable, and we have hardly begun to discuss them.

The University of Oxford/Murdoch story shows where insufficient attention to the risks can lead. THE's report, the first to focus on Murdoch's Oxford connection, was headlined "Oxford steadfast on Murdoch links". Other sources followed it in reporting that the university did not intend to review the association. But that was not exactly what the institution's press statement said.

After rehearsing the basic facts about the benefaction (how much it was, what it paid for, etc), the statement noted that it had undergone a full process of scrutiny when it was first offered in 1990. From this it seems to have been inferred that Oxford would not be revisiting the issue. In fact, the university's policy is that donations can be re-examined if new circumstances warrant it. But that point was not made clear, and when the news reports made Oxford's supposed commitment to doing nothing their central focus, no one intervened to clarify it.

This lack of attention to (ironically) communication has had unfortunate consequences, since to most people it is self-evident that something has changed since 1990. Murdoch is now alleged to have presided over an organisation that systematically engaged in illegal practices, such as phone-hacking and bribing police officers. If the allegations are shown to be true, that must raise ethical questions of a different order from the ones that were considered originally. Unsurprisingly, commentators criticised Oxford for what looked like a refusal even to consider that.

Of course, some might say that drawing the line only at the point where a donor is implicated in actual criminality is setting the bar too low; they might also say (some THE readers already have) that Oxford's only ethical option is to return the original donation. But the apparent moral clarity of that position is deceptive, for in practice it might only mean replacing one set of ethical dilemmas with another.

In the midst of the furore, a friend who also holds a named chair told me I should think myself lucky that mine is only named after someone like Murdoch. His own chair is named for someone associated with a political regime that you wouldn't have to be a paid-up member of Amnesty International to find distasteful. He is certainly no defender of it, but he works in one of several academic disciplines whose continued health in UK universities depends heavily on the support of people such as his benefactor. Soon we may all face the same dilemma: if we want to maintain acceptable standards of provision in a climate of public austerity, how scrupulous can we afford to be about the alternative private sources? Is taking cash from despots more or less ethical than, say, recruiting more high-paying overseas graduates than our resources allow us to supervise properly?

People talk about tainted money, but what money do they think is clean? When you get right down to it, almost all private cash is at least potentially tainted. Even foundation money might make us queasy if we really stopped to consider the source: Carnegie and Rockefeller were the Murdochs of their time. The kind of capitalist fat cat who can give you several million pounds is fairly unlikely to have lived the life of a saint. At any point in your association with a donor, some financial risk he once took or legal corner he cut could come to light and cause a scandal; he could also be revealed as a polluter, an exploiter of child labour or a serial sexual harasser. The risk is greater now than in the past because of the intensity of the media's interest in uncovering the past misdeeds of the rich and powerful (an irony presumably not lost on Murdoch). Consequently, universities can never know for sure that a deal with a high-profile donor won't blow up in their faces later on. And if it does, what should they do? Jobs, courses, scholarships may all depend on that money: giving it back might be good PR, but it will probably hurt the innocent far more than it hurts the guilty.

I'm not writing to protest my own innocence, to show that I'm not the fool, knave or corporate lackey conjured up in recent press comments. (For the record, News International has never shown any sign of wanting a lackey: it has honoured its obligation not to interfere with my activities or limit my freedom of expression.) Nor am I writing to defend Murdoch, or to protect my own interests because my job is on the line (in fact, my understanding is that if Oxford returns a donation, it also assumes responsibility for any posts the money funded). I'm writing because recent events have raised what I believe are important issues for universities and those who work in them. But so far it seems no one has been interested in addressing the difficult questions: any complexity has been drowned out by a mixture of name-calling and high-minded disgust. How does it feel to be the Rupert Murdoch professor? Right now, in a word, it feels lonely.