Great novelists and philosophers can have that effect on young people approaching exams. But in this case it was more a glint in the sculpture's eye. Koestler has fallen victim to the curse of biography. His private life is damned in a recent book. Thus his works and literary reputation must be damned too.
We have tended to take a lenient view of great artists indulging in sexual activity. But a new rash of revelations have moved on from sex to sexual politics. And here the issue is not so clean cut.
Where Sir Richard Burton's wife, for years damned as a wet towel to her husband, is reconstituted as his saviour in a new joint biography just out, a televsion documentary to come out later this month does the opposite for Clara Schuman. Once portrayed as her husband's guardian angel, the director claims she destoyed his best work and left him alone in his asylum at the end.
Once biography moves into the bedroom, who is safe? What if a great artist was guilty of sexual harassment? What if he were a rapist?
The last is particularly pertinent. A biography of Koestler, the supposedly great humanitarian and champion of civil liberties in his fiction, exposes him as a serial rapist. Jill Craigie, the novelist wife of Michael Foot, confirms how Koestler several decades ago abused her hospitality, hurled her to the floor in her own home, and raped her.
The biography claims that rape was "almost a hallmark of his conduct". And the women of Edinburgh have had their literary tastes altered for good - and the bust removed.
This is a new twist on where to draw the line. Should the private life of an author lead to the removal of his statue in public places? Let's hope no damning biography is being prepared on Sir Walter Scott. The politically correct students of Edinburgh will demand a remodelling of Princes Street.
The author of the Koestler biography, Professor David Cesarani, concludes that Koestler should be seen "in the round" as a person who had done disgraceful things, but who was a heroic campaigner.
There is an alternative view: namely that he should not be "seen" at all, his work should. Instead of balancing the heroic and the disgraceful in a literary gamble that the author might emerge on the right side of the moral line, his books still saleable, his bust unthreatening, might it not be more constructive to judge an author purely on what is written, a composer purely on the music produced. Terry Eagleton, the Oxford, post- structuralist academic, is one who believes the text is all and despairs of "the English mania for biography".
It is a British weakness, he says, that we seem less interested in ideas than in the sexual habits of those who had them. "The narratives we relish are not fictions, but the real-life stories of fiction-makers."
The female students of Edinburgh will have to avert their eyes from the newly suspect gazes of the following: George Orwell, we recently learned, shopped communists to the intelligence services. Shakespeare, to the bizarre outrage of some feminists, left his wife the home's second-best bed in his will. The much loved but adulterous composer, Janacek, was a stinker to his missus, her newly published diaries reveal; Einstein's theory of relativity did not include being true to the relatives. He not only had an affair, but it was with a Russian spy. So that should create some much needed space on the bookshelves and CD racks. Gets rid of a few city centre statues too. And the BBC can expect a demo by militant feminists outside Broadcasting House if the Today programme makes Shakespeare its man of the millennium.
Despite the presumptuous theories now current about how he treated his wife, the great thing about Shakespeare is that he never gave an interview, appeared on a chat show, wrote an autobiography or even a programme note. We have to judge his plays on their merits.
The massive irony in the literary revaluation following revelations about the author (or bust removal as it might come to be known) is that we only read a literary biography in the first place because we have been impressed by a book and want to know more about its author. To then reject the virtues we first noted in the book because we discover that the author was a less than perfect human being may have moral worth; it certainly has no aesthetic or academic worth. No one would suddenly find a much-loved building ugly because of a negative biography of the architect. A work of literature or a piece of music are no less worthy of objective judgement.
And yet I have to admit it is hard not to have a problem with Koestler. Had he written detective stories, then his appalling attitude towards women would probably not affect one's critical appraisal of them. However, it does become a little difficult to read Darkness At Noon, his sensitive and distressing portrayal of life under Stalin's torturers, without a feeling that he was no slouch at inflicting pain, trauma and distress himself.
But Darkness At Noon was a work of fiction. Koestler was not Thomas Jefferson, who preached liberty from a public platform. And even revelations about Jefferson do not demean the essence of his message. Once published, a novel transcends its author; its message and theme transcend its creator's private life. If not, then where do we stop? Do we dismiss the melancholic glamour of Graham Greene's anti-heroes because the latest biography of him reveals that, into his sixties, he never travelled without his teddy bear?
Artistic creations must be used and judged in their own vacuum, free from their creators' weaknesses, moral failings, even criminal acts. It is not that long a road from removing busts to burning books.
Perhaps the students of Edinburgh should replace the bust and put underneath it the words: "Curling up with a good book is not the same as curling up with the author." What matters is the work produced. Great artists don't have to be nice. Very often they were, and are, cussed, selfish and hell to live with.