02/05/2016 18:17 BST | Updated 03/05/2017 06:12 BST

Defining Racism: What I Say Doesn't Go

As the scandal of anti-semitism on the British left rumbles on - and in Ken Livingstone's case it's been rumbling for quite some time - we are hearing more and more of the notion that minority groups should have the final say in defining what does and does not constitute a racist attack on them.

In other words, this means that if X is a member of racial group Y, and they think that comment Z is a racist attack on racial group Y, it is a racist attack on racial group Y and that's the end of the matter. Similarly, women have the final say in identifying sexism, members of the LGBTQ community in identifying homophobia, and so on.

This approach stems from the Macpherson Definition, so called after retired judge William Macpherson who conducted the 1999 Stephen Lawrence Inquiry into institutional racism in the Metropolitan Police:

A racist incident is any incident which is perceived to be racist by the victim or any other person.

This definition is superficially attractive. But one only has to think about it for a moment to realise that it is plainly wrong. A few examples illustrate this:

Firstly, there are cases where something is clearly not racist, regardless of what anyone has to say on the matter. Take the Seinfeld scene in which Uncle Leo receives an overcooked hamburger in a café and exclaims that the chef must be an anti-Semite ("They don't just overcook a hamburger, Jerry!"). The chef didn't see their customer. They didn't know he was Jewish. There was no evidence to suggest that the hamburger was overcooked deliberately. Anti-Semitism was very obviously absent from the whole episode, whatever Uncle Leo thinks.

William Macpherson may treat it as a racist incident on the basis that Uncle Leo labelled it as such; but that only serves to cheapen the concept of racism and make it something to be mocked, not abhorred.

Second example: contradictions and inherently contested concepts. Lots of Israelis think that labelling their state 'apartheid' is racist; lots of Palestinians think that to deny Israel as an apartheid state is racist.

By Macpherson's definition, they're all correct. Israel is simultaneously a racist incident and not a racist incident. It is Schrödinger's dream come true. It's also complete nonsense.

There are plenty of other examples of outright disputes in the world of racism: is positive discrimination racist, or is a refusal to introduce positive discrimination racist? There are powerful voices, and arguments, on both sides. Adopting an inflexible definition shuts down what is actually an important debate for society to engage in.

Third example: 'racist' used as a smear. Sadly, it is a well-known fact that some unscrupulous people will call others racist in order to evade scrutiny and get away with wrongdoing.

Take Lutfur Rahman. When his election as Mayor of Tower Hamlets was found to have been riddled with intimidation, lies and downright fraud, a High Court judge removed him from office. Rahman responded by claiming he was only being targeted because of his Muslim faith.

The Macpherson definition says that, because Rahman perceived his trial to be racist (or because he said he did, since in the absence of telepathy we have to take him at his word), his trial was racist. But if we accept that, then he is able to evade justice and continue as mayor despite his corrupt path to power. That cannot be right.

Similar things can be said about claims that the new president of the National Union of Students, Malia Bouattia, is only being criticised because she's black/ Muslim/ a woman. Actually she was being criticised because she had a history of making anti-Semitic remarks grossly offensive to the Jewish community; but again, Macpherson says that if she perceived the backlash against her election as racist, it was racist. Again: balderdash.

So the Macpherson definition is no good. A system where a person gets the final say as to whether or not hate speech has been perpetrated against them is open to abuse, self-contradictory and totally unworkable.

The views of those who perceive themselves to be targets obviously have to be taken into account. And sometimes - perhaps often - when there is a consensus, those views will have overwhelming weight. Anybody who is not part of a targeted minority should be very careful before disputing a claim that someone has been the victim of a racist incident.

But there are times when that approach is absolutely appropriate. The ability for society to function and to engage in critical discussions is too important for William Macpherson - with his absolutes and his certanties and his lack of space for discretion or exception - to overrule.

So next time you hear someone say as fact that if a person thinks they've been a victim of hate crime then they have been the victim of hate crime, end of... just remember Uncle Leo's hamburger.