It's 2010: the years have moved on by one notch. At the same time, the calendar circles back to 1 January, giving us the illusion that we can start everything afresh. Some of us think of this as just another day, perhaps an uneventful and hungover one. For others, it means something more vigorous: making resolutions, wiping clean the slate, rejecting old inadequacies and trying to do the right thing, starting now.
All this determination can make us feel good for a while - but what happens next? If our resolutions subside into half-forgotten good intentions by mid-January, are we going to feel worse than if we had never made them? Will we forgive ourselves less, or more, than if we break a similar plan made in mid-August? Is there something about today's date that sets us up for a special sense of failure? When our old selves come back, with their lazy ways and imperfections, refusing to go to the gym or tile the bathroom or get to bed early, will we greet them as familiar friends, or let them depress us?
I don't want to feel like a failure in 2010. I am making no resolutions and will be looking for wisdom from a different source: a man who knew a lot about living and had no patience for wiped slates or clean breaks.
He was Michel Eyquem de Montaigne, the author of a book named simply Essays, a word he coined to mean "tries". A wine-growing nobleman and Bordeaux government official of the late 16th century, he slipped away from his work and home responsibilities as often as he could to attend to his real labour of love: writing digressive, entertaining, freewheeling thoughts about all that he had read, done or seen.
He spent 20 years filling these with anecdotes and observations, until they occupied three volumes loosely grouped under titles such as "Of Friendship", "Of Coaches", "How we cry and laugh for the same thing", "How our mind hinders itself", "Of Experience" and "Of Thumbs".
The titles often had little to do with the content, but this did not bother either Montaigne or his passionate admirers - for the book met with huge success on its first publication in 1580, and has remained famous ever since. By putting it into the world rather than keeping it to himself, Montaigne was breaking a taboo.
You were not supposed to publish books about yourself, unless it was to record great deeds for the benefit of posterity, or a spiritual quest like that of St Augustine. But Montaigne wrote about eating, scratching his ears, having sex, reading books, talking to neighbours, catching himself being absent-minded or vain or impulsive, sleeping, falling off his horse, playing word games with his wife and daughter, and watching his cat hunting birds.
His real subject was simply Michel de Montaigne: the experience of being himself, an ordinary human leading a fairly ordinary (if privileged) life. His frankness, wit and insight delighted his readers, while giving them a mirror in which they could recognise their own habits and emotions.
As with all of us, some of the things Montaigne did were flawed, and he makes no attempt to conceal this. He lets us see him being petty, lazy or ignorant, or doing things that no longer make sense to him. Yet it is all part of himself, and he accepts it all. "I rarely repent", he says - a strange admission for a good Catholic. He writes, with great cheer, "If I had to live over again, I would live as I have lived." It is enough just to be the way he is.
This may sound easy, but self-acceptance is one of the hardest things to achieve. Montaigne manages it partly by treating his past selves as separate individuals. Whatever he did in the past, he was someone else then, and it must have seemed right at the time, so why worry?
Even five minutes ago, he was different, and soon he will be changing again. "We are all patchwork," he says, "and so shapeless and diverse in composition that each bit, each moment, plays its own game." Every minute means a different Montaigne, and a kind of New Year leap takes place at every breath, not just at ritually designated thresholds.
Montaigne could have made New Year's resolutions: they were well established in his day. The Romans had looked back over their past actions at the end of each year so as to plan for the year ahead. When Julius Caesar re-organised the calendar in 46 BC, he set the year to start on 1 January - a month named for Janus, two-faced god of portals and gates.
Montaigne admired Roman traditions, but this particular one ran counter to his temperament. It was the moment-to-moment flow of everyday life that fascinated him, not gateways and rites of passage. He loved looking into his past, but mainly because he was curious about it and wanted to reflect on the variety of his behaviour and experience.
As for the year to come, there was no way to separate it from the general onward flow, or make it adhere to different rules from what had gone before. It is no good climbing on stilts, he wrote; you must still walk on your own legs. And however lofty your throne, it will still always be your own rear end you are sitting on.
He did think, though, that valuable lessons could be learned from looking over a life and taking a longer perspective. Instead of clean breaks and new intentions, what Montaigne sought in his past experience was greater self-understanding. There would always be puzzling areas, but he tried to become familiar with his weaknesses so as to work around them. This is a matter of practical good sense. If, instead of fooling yourself about your nature and making futile resolutions, you understand that you are just too incorrigibly lazy ever to get out of bed at 5 am and start work early, you can look for more appropriate ways of planning your time, or perhaps find an easier job.
Taking accurate stock of weaknesses has another benefit, which goes to the heart of Montaigne's philosophy - if you can use the word "philosophy" of a book which sets out only to describe one man's assorted experience of life. By understanding and accepting your fallibility, you give yourself a means of minimising one of humanity's most damaging tendencies: that of taking personal beliefs and perceptions to be universal truths.
Most people commit this error without realising it. If something looks green to your eyes, it is only natural to think that it really is green, no matter how many other people say it is blue. But if you remember other occasions on which your eyes have fooled you, whether because of optical illusions, fever, or tinted lighting, you are more likely to pause before picking a fight over it. Should the subject be politics or religion rather than the colour of a wall or scarf, the result is a small but significant decrease in the amount of militant bigotry in the world.
Because it kept his mind open, Montaigne welcomed any experience that reminded him how error-prone he was. He even celebrated when he caught himself in a memory lapse, because it made it obvious how little he grasped about the world. If a friend remembered some incident differently, he willingly accepted the friend's version, knowing how wrong his own ideas had been in the past. And he hoped that, should he ever become hard of hearing, he would doubt himself at once, rather than insisting as most people did that those around him had begun whispering and mumbling.
So, if we choose to look back on 2009 and decide that we have done wrong-headed or undesirable things, we are making a small but significant contribution to improving humanity, by becoming more sensitive, less blinkered, and more willing to consider alternative points of view. We also gain useful personal tools for making decisions based on our limitations.
This is very different from making resolutions. It does not mean rejecting past actions, but accepting and even embracing them in order to become what Montaigne calls "wise at our own expense".
With such a source of wisdom at his disposal, it is unsurprising that Montaigne paid little heed to the usual doorways and thresholds of life. He found it more rewarding to observe the river of human experience as it ran through him, from moment to moment, and to question every drop of it. The result, his Essays, is a book filled with real life and rich with ad hoc, accumulated insights into the art of living well.
I make no pretence to knowing how to live well - but maybe this year I will just lie back and accept that fact. I will also do what I have done many times before: read Montaigne, savour his wisdom, enjoy his company, and remind myself to keep marvelling with him at the strangeness of life.
Sarah Bakewell's 'How to Live: A life of Montaigne in one question and twenty attempts at an answer' is published this month by Chatto & Windus. Montaigne's 'Essays' are published by Penguin Classics