‘SOME PEOPLE ARE GAY. GET OVER IT.’ That slogan was posted on London buses in 2012. It was aimed at some Christian groups who understood human sexuality not as a spectrum of many shades but as a stark choice between right and wrong, the permitted and the forbidden.

Many of us are prone to this kind of binary reductionism, but it is amplified and exaggerated by religion, because its favourite discourse is the adversarial. You are either for it or against it. There’s nothing in between.

Apart from anything else, this is a very boring way to look at the world. Louis MacNeice got it when he wrote: “World is crazier and more of it than we think / Incorrigibly plural.”

The tragedy here is not just the absurdity of trying to purge the world of its crazy variety, but in the pain and hurt it causes those who can’t or won’t force themselves on to our reductionist templates..

The latest collision between the glorious variety of humanity and the dreary compulsion to split it into opposing pairs is in our attitude to gender. Now we recognise that gender, like sexuality, is fluid and plural. And in some people it may never be permanently determined. It might even shift during a single lifetime. Humans are incorrigibly plural. If you’ve got a problem with that, it’s time you got over it.

Humans are incorrigibly plural. If you’ve got a problem with that, it’s time you got over it

It’s also time the leaders of faith communities, and their equally passionate opponents, realised that human approaches to religion are varied. There are those who are firmly in and those who are firmly out of religious institutions. There are those whose belief is strong and those whose unbelief is equally unyielding. And like the majority of the population whose gender and sexuality are clearly printed, they are the ones who claim to define the territory for the rest of us. But there are as many hues on the religious spectrum as there are on gender and sexuality. We should acknowledge that and come to a more generous and comprehensive understanding of this aspect of human experience.

There are those for whom religious observance is a way of guaranteeing comfortable accommodation in the life to come after death. Their gaze is mainly on the other world and how to get there. But for an increasing number of us life after death has no attractions and we doubt that it exists. It is life before death we want to concentrate our attention on.

Our religious energy has shifted from belief to action and from creed to compassion. And we find that listening to the wisdom of its wisest teachers helps us to do that. We think of ourselves as belongers rather than believers. But we don’t want to persuade believers out of belief any more than we want them to persuade us into it. What we want is to join them in making life better for everyone and let what happens after death take care of itself.

The gulf between us is not so wide. Those who believe in life after death warn that its quality depends on how we have lived in this life. Doing good while we are on our earth may secure us everlasting habitations in the world to come, but it will also leave this world a better place than when we entered it. And that is exactly what those of us with no interest in eternal life want, too. Our motives may vary but the result will be the same.

But in my experience if you take this approach to religion you get caught in a withering crossfire. Both the champions and despisers of religion attack you with equal fury. It’s that old binary game. You have to be one thing or the other, they yell. You cannot be both or anything in between. Well, tough. Some of us are. Get used to it.

A Little History of Religion, by Richard Holloway, is published by Yale at £14.99. Order a copy for £12.29 at bookshop.theguardian.com