I am a “lefty”. I have voted Labour all my life. I believe in the abolition of public schools and the inviolability of the NHS, and that the renewal of Trident is a vanity project. I believe the state must work to ensure equality of opportunity for all: women, the LBGT “community”, those with disabilities, those of minority cultures and ethnicities, and the working class. The Guardian has been my newspaper forever. I was glad to see the back of the Sun’s Page 3, and I believe there should be more all-women shortlists for parliamentary seats. I believe immigration is more of a positive force than a negative one.

However, you might be less certain about my status when I finish laying out my stall. Because I find myself holding a “transgressive” body of beliefs and doubts alongside my blue-chip leftwing ones that are liable to get me branded a misogynist, an Islamophobe and a Little Englander – at least by people on my Twitter feed, and others of my peer group.

These “beliefs” are more like questions, largely about identity politics, those deep and dangerous rift valleys of the left. I believe the jury is still out about whether gender identity is entirely constructed. I question whether the gender pay gap in Britain is as large as is sometimes suggested, and wonder whether it may have as much to do with the way it is calculated and with the choices women make after having children as it does with patriarchy or prejudice (although the government could do more to close the gap by funding childcare better). There is huge work to do to liberate women from the very real yoke of patriarchy. But I would venture – checking my privilege – that this is not a crisis in Britain in way it is in the developing world.

Facebook Twitter Pinterest ‘I think of myself as English rather than British, and have some residual affection for my country.’ Photograph: Mia Caruana / Alamy/Alamy

I am not convinced jihadists have “nothing to do” with Islam – although this strikes me as a largely theological and semantic point. I am wary of even moderate Islam for the same reason I am wary of even moderate Christianity: because I am an atheist and a humanist and a social liberal, and consider most religions to be counter-rational and socially conservative. To acknowledge that grooming gangs and FGM and tendencies towards homophobia and gender oppression have arisen out of some of the matrices of Muslim practices and belief systems adds to my unease.

I believe more in free speech than I do in “safe spaces” in universities. I do not think people with unpleasant opinions should be prosecuted, or even denied a platform, unless they directly threaten to incite violence or lawbreaking. I do not think “political correctness” is a myth – although I would prefer the term groupthink – but that it is a system of thought that has a real impact on public policy and institutional behaviour.

I think of myself as English rather than British, and have some residual affection for my country – though for reasons of its humour, cultural imagination and common grassroots culture rather than its imperial past.

My stance on these issues makes some people in my “tribe” very angry. It is the anger of the pure believer towards the apostate. However, I can find echoes of my populist worldview in one strand of the left – that represented by the Spiked web magazine, which grew out of the ashes of Living Marxism and the Revolutionary Communist party, once known as the libertarian or anti-Stalinist left. Describing their philosophy as radical humanism, they poke and prod at the sacred cows of the left but from a socialist rather than a rightwing populist position. The fact that I enjoy Spiked – although I by no means agree with all of it – feels like dirty little secret. But that’s what the mainstream left specialises in: generating shame.

My stance makes some people in my tribe very angry. It is the anger of the pure believer towards the apostate

This shame comes from the phenomenon of what I call assumption creep – the assumption that if you believe one thing you probably believe another thing, which you are hiding. If you believe women behave differently in the real world from men, whether for cultural or biological reasons, you also (secretly) believe women are more suited for domestic life than careers.

That if you believe religion, including Islam, is the source of much conflict in the world you also (secretly) believe all Muslims are potential terrorists and you (secretly) dislike immigrants to boot. That if you have a particular attachment to your country, defined as England rather than Britain, you keep a St George’s flag and a knuckle-duster in the back of your drawer. These supposed secret assumptions are the primary source of censure from leftwing critics of the “paradoxical voice” – which is the term I use to describe the thinking of “non-pure” leftwing thinkers.

Assumption creep may be accurate in some cases. We all know about the “I’m not a racist, but … ” arguments. But more often than not, it simply isn’t true. To insist otherwise is lazy. It’s just a way of making sure people who have opinions contrary to your own stay safely in their boxes – the boxes marked “bad people”. To actually address the issues is thus avoided, because who needs to debate with a bad person? It’s enough just to condemn them.

One very key element of the liberal left has long been under threat: its liberalism – that is, its willingness to debate with anything outside a narrow range of opinions within its own walls. And the more scary and incomprehensible the world becomes, the more debate is replaced by edict and prejudice: literally pre-judging. Identity politics is one of the most significant developments of the last 50 years, but it has led to nerves being exposed in a way they rarely were by economic issues. Because identity is less about politics and more about that most sensitive of human constructions, the protection of the self – both group and individual.

The more scary and incomprehensible the world becomes, the more it is replaced by edict and prejudice

And the more it becomes about the protection of self, the less it becomes about the back and forth of rational argument. All the beliefs, opinions and doubts I hold are just that: they are ideas, not ironclad convictions. I am not certain about any of them, and am quite willing to change my mind, as I have done many times in the past. But I will not alter them if I am faced with invective rather than debate; in fact, they will become more entrenched.

Nick Cohen, Christopher Hitchens, David Aaronovich, Julie Burchill, Julie Bindel and others have often been at the rough end of this debate, for daring to voice opinions of their own that do not fit the overarching narrative. David Mamet’s admittedly provocative essay, Why I Am No Longer a “Brain-Dead Liberal”, published in the Village Voice, must have cost him a fair few dinner party invitations. This marginalisation is invidious, not only because it violates the principles of free debate – we cannot suppress awkward questions lest it “give succour to the enemy” – but because it is bound to alienate the wider public.

Those who identify with the “paradoxical voice” self-censor because they know they are going to get rocks thrown at them – not by their enemies but by their friends. That’s not only a bad feeling; it’s a tendency that’s bad for democracy, for politics, and the wider movement we call the left. And the left – in its compassion, freedom and concern for social justice – is the only hope for the future of this country.