Will Self is a celebrated writer of fiction and journalist. Born in London in 1961, he can also boast an illustrious ancestry. His paternal great-great grandfather was the Bishop of Chichester. His grandfather, Sir Henry Self, as well as having been a distinguished civil servant (responsible for securing a supply of American fighter planes for the RAF during the Second World War) was also a practising Christian. His father, Peter, with whom I was slightly acquainted, was professor of public administration at LSE.

Whether Self is proud of this lineage I know not: he certainly has every reason to be. But on his mother's side there is, apparently, a problem. Professor Peter Self "married out". His bride, who hailed from the borough of Queens, in New York, was Elaine Rosenbloom who was Jewish.

This makes Will Jewish -as Jewish as the chasidim of Brooklyn or Stamford Hill. And of that he is - apparently - not proud at all.

It was not always thus. In an interview published in New Humanist in 2003, he explained that "Jewishness was something that was only partly acknowledged in our family. It was either oddly embraced or oddly rejected so much so, for example, that my brother doesn't even think of himself as being that Jewish, whereas I do tend to."

But not any more. Writing in last week's Guardian, he reminded us that, in 2006, he had very publicly (via the Evening Standard) "resigned" as Jew. "My resignation (he explained) wasn't a protest against Israeli aggression - why would they care about such a gesture? - but aimed, I believed, against prominent left-wing English Jews, who, despite the complete contradiction between their espoused values and the undemocratic, apartheid and territorially expansionist policies of the so-called Jewish homeland, continued vociferously to support Israel."

Quality of Jewishness has very little do with one's belief

For present purposes I'm going to ignore Self's polemically sweeping - and frankly crass - denunciation of "the so-called Jewish homeland". My concern is rather with Self's apparent conviction that being Jewish amounts to nothing more than belonging to a club, from which one can simply tender one's resignation. It isn't.

The quality of Jewishness has little to do with religious belief. And it's certainly not a racial construct, narrowly defined. It is, rather, an ethnic category, meaning that its members enjoy a shared ancestry or history, or a common geographical origin, a shared linguistic characteristic or perhaps simply a broad cultural commonality. Politics does not come into it. If Self wishes to raise a personal flag against the policies of discrete Israeli governments he can certainly do so. But what he cannot do is to signal this distaste by denying his ethnic origins, because these are indelible.

Indeed, on re-reading his "resignation", I was reminded of those sad individuals who demand that their Google search histories be erased. Of course they can be erased; but erasing them does not expunge the historical records to which they link. The past can be reinterpreted. But it cannot be expunged.

Self also harbours the delusion that Jewishness is a matter of self-ascription. "What people think they are (he insists) is undoubtedly their own affair." I'm afraid it isn't. This isn't a matter of halachic interpretation. It's human nature. I have a friend who was born to Jewish parents in Nazi-occupied Austria. Out of desperation, the family underwent baptism. Of course, this did not save them. The parents perished in the Holocaust and my friend was lucky to have escaped to England days before the outbreak of war in 1939. He remains a practising Christian. But he has no problem – now - with identifying himself as a Jew.

Will Self may genuinely believe that by "resigning" as a Jew he will render his antagonisms towards Israel more acceptable. It won't. If he wants to take part in movements that are opposed to the idea of Jewish national self-determination, let him do so as a Jew, for that is what he is. But I fear that, in seeking to deny and erase his Jewishness, he will succeed only in heaping ridicule upon both himself and his views.