Although I’m a card-carrying atheist, I have some sympathy with those who argue that a Christmas without Christ or a mass is as meaningless as celebrating a birthday without a birth, or a jubilee without a coronation.

However, traditions have a habit of breaking free from their roots. Nobody is calling for Saturday or Wednesday to be renamed because we no longer worship Saturn or Wōden, the Roman and Norse gods who gave the days their names. The fact that hundreds of years ago our pagan midwinter festival was refashioned and renamed after Jesus does not give Christianity ownership of it in perpetuity.

Disgruntled Christians would do better to seek common cause with anyone else, including thoughtful atheists, who wants Christmas to stand for more than just shopping and gorging. If they did so, they would see that a good atheist Christmas looks a lot like a good Christian one.

The nativity myth centres on the birth of a child, but you don’t need to believe in the tale of the manger and the Magi to use Christmas as a time to celebrate the family, in spite or perhaps even because of its strains. The distasteful consumerism of Christmas today is simply an excess of a laudable desire to put extra resources into a once-a-year coming together.

This should foster gratitude, which in turn draws our attention to those who lack family support or the material resources to push the boat out. So Christmas is also a time of hospitality and generosity. Many will be inviting people outside their families to share their Christmas lunches, while seasonal charity appeals (including that run by this newspaper) show that splashing out on ourselves is not incompatible with caring for others.

Most obviously, Christmas is in effect a celebration of the winter solstice, four days late. Christians might think this is impious paganism, but all human cultures mark the passage of the seasons, whether they worship gods, nature or nothing at all. We can all be cheered by the lengthening of the days and the prospect of spring.

Much of the value of Christmas is the same for anyone, irrespective of religious faith, or lack of it. But just as Christians bring their own distinctive faith to the holiday, so atheists appreciate an aspect of it that remains inaccessible to believers.

Atheists are not just people who don’t believe in God. Put positively, our belief is that the natural world is all that there is. Only by fully accepting this fact can we live good lives that are true to our nature. The marking of midwinter brings these truths home. It reminds us that the cycle of life and death turned for aeons before we were born and will continue its rotations for aeons after. It exemplifies the legitimate hope that darkness can be followed by light but not the false hope that we can ultimately escape the fate of all living things. In our feasting, we are asserting the value of appreciating the good things while we have them, while remembering that nothing is meant to last, for good and for bad.

These beliefs are not for the most part shared with Christians. But the solemnity with which we meditate on them and the joy with which we act on them very much echoes their blend of moral seriousness and festivity at Christmas. By remembering we’re all just trying to work out how to live good lives in the harshness of a sometimes cruel and perplexing world, we can share the Yuletide hope for peace on earth and goodwill to all.

A Short History of Truth: Consolations for a Post-Truth World by Julian Baggini is published by Quercus at £9.99. To order a copy for £8.33 go to bookshop.theguardian.com