I first worked out that I was a small c conservative, long before the idea of being a big C one had occurred to me. It was on Friday evenings when my sister came back from youth club study group and started changing the tunes we used for the grace after meals.

Objectively, her new tunes were better than the old ones. My father was a great student of Judaism, but no one could ever successfully accuse him of being musical. But the superiority of the tunes wasn’t the point. The new tunes weren’t our tunes, the ones we had always sung.

I worried that we would forget the old ones, lose the tradition, and that, once we had started down the new road, there would be no turning back. I was right, too. I resisted at first but gradually gave in, one little melody at a time, disarmed by the fact that we were making things better.

And, now, on Friday nights I no longer know what is Dad’s and what is study group’s, what is my brother-in-law’s and what my wife’s. The change has happened and the past has been overlaid.

It is irrecoverable but the melancholic feeling that should induce is suppressed by a feeling that what we have now is ours and the product of our collective striving to make things better.

I didn’t realise that first time at the Shabbat dinner table but I was encountering one of the great tensions of my life, a constant theme of my politics and my religious observance. The tension between tradition and progress.

This thought was brought to mind recently when I was granted the privilege of helping to launch a wonderful new book— Being Jewish Today — by Rabbi Tony Bayfield. Accepting the invitation actually was partly an affirmation of family tradition — a longing look backwards. My father had dearly loved Rabbi Bayfield and respected his leadership of the Reform movement. He would have wanted me to be there.

But it was also a look forward. Because the theme of Rabbi Bayfield’s book is how to understand Judaism now that science and modern sensibility has changed the way we look at the world. And this addresses problems I struggle with all the time.

I cannot just dismiss science, pretend Charles Darwin was wrong, accept the Torah as pure history. I can’t accept the idea that homosexuality is wrong or that women should be consigned to a subsidiary role in worship and banished to a separate (and, let’s face it, inferior) part of the synagogue.

But I am also a small c conservative. With change, comes loss. I understand what motivates those who cling to what we have. There is always this question — when have we changed so much that what we have is unrecognisable? Have we pulled out so many Jenga bricks that the next one will make the tower collapse?

When I first accepted my doubts about the nature of God, and realised the doubts wouldn’t go away, it shook me. I wondered if I’d be able to carry on, wondered if it wouldn’t just seem pointless.

Yet, somehow, this isn’t how it played out. I’m more engaged with Judaism now than at any point in my life. I have found a way to live with the tension.

Rabbi Bayfield deals with all this (and a lot else, by the way, so buy the book and take a look) with great sensitivity.

He argues that Judaism is a journey and we are all on it individually and collectively. For each of us, the journey is different but we all take one.

It is ahistorical to suggest that Judaism must stay as it always has been, because the one thing it has always been doing is changing.

In his recent book on language, Accidence will Happen, my Times colleague Oliver Kamm makes a similar argument. Language keeps changing, there is no one true language and no authority that says definitively what is correct and what is not.

All that matters is that it be comprehensible and useable. Language bends but it never breaks.

And I think the same is true of Judaism. The path winds but you can still find your way along it. It is hard to find ones way back, but the future stretches ahead.

Daniel Finkelstein is associate editor of The Times