Robert Rowland Smith: New year, new you – and there is plenty more of both...

Living longer than ever, we can reinvent ourselves, time after time

(Alamy)

Sigmund Freud, who founded an entire science on helping others to sublimate their fantasies, retained a fantasy of his own. For all his preoccupation with the erotic, however, it was nothing sexual. No: Freud's deepest wish was the eradication of death, the possibility that it would one day be conquered and laid aside as a biological snafu, a throwback to the matinal confusions of the hominid. Deathless humans of the future would look back on us mortals with the pity we ourselves apply to those hapless denizens of the pre-modern world who died of toothache or the clap.

Freud's fantasy might sound naive, but with the news that one in five Britons is now likely to live to 100, it's just inched closer. We're inclined to accept as axiomatic that longer life is to be wished: but what will we do with all the extra time?

The question takes on extra puissance at the beginning of another year. If the evidence about living longer is right, we're only going to have more New Years, and, with them, more milestones to reflect on the increasing number of anniversaries we've amassed. And this despite the fact that many of our most significant events will continue to occur in the first 25 years or so: learning to walk, talk, ride a bicycle and swim; starting school; casting a first vote, going to work; losing virginity, falling in love, getting married, having a child.

Doesn't longer life just mean ever more time to sift through memories of these same early experiences that will only become more distant, less reliably collected by our recollections? Clearly, it would be better to have a richer picture of what exactly a longer life will be filled with.

To do that, we need to understand time itself, and let go of some illusions. Philip Larkin remarked that "no matter how we use it, it goes". Having more time doesn't mean we'll use it well. Besides, as it goes, we go too. Because it ushers in another year, January might make the truism feel truer, but it was ever thus: you've never been as old as you are now, even if you're relatively young.

When I thought about this as a teenager, it would give me a species of vertigo, the sense of pressing at the edge of time, hurtling like the discus of the Starship Enterprise into the starry blackness, lathing my own being into being. This was more than the teenager's legendary inability to think beyond today: this was existential. But I didn't take much notice of the moral aspect of ageing, that is – if you're as old now as you've ever been, are you getting any better as a person? You've never had more experience, nor more opportunity to reflect on it, than you do now. You should be ever arriving at a new peak, superseding the one just gone and anticipating the next.

If only. For most people, "now" doesn't feel like the edge but the middle: ask them how they are and they'll say "fine", a word that suggests they're neither here nor there, but caught up in the general vague motion of things. There'll be a past, the most preoccupying portion of which will be what's happened recently – a family argument, a crisis at work. And there'll be a future, also bunched up near the present, with a wispy trail out into a nebulous future that features hazy images of living in the sun, say, or selling your business for a tidy sum.

Technically, the future doesn't exist. What we designate by that name is merely an inner fantasy, but it's enough to take the edge off the edge – to give us the illusion that the future's already there for us to amble into at leisure and shape according to our fancy. The illusion excuses us from taking an absolute measure of ourselves here and now: no, we're not at our best right this minute, but later this year we might well be.

Especially as the new year begins, we like to think of time as the medium of advancement, the very resource required for becoming fitter, happier, fulfilled, enamoured. When we then look back over the year just buried, we realise that time serves other, less wholesome masters, like inertia, failure, bad luck, and self-subversion. Only so many of last year's resolutions were kept. Hence a second illusion about time: we construe it as a force that can tend to the good or the bad whereas, like water, time is completely neutral; it has no point of view about us or our fate, and only lets things happen.

The result of time's openness to both good and ill is that, as the years pass, there's no presumption in favour of us improving. We're just as likely to go downhill, and get more embittered at our own decline.

This equivocation at the heart of time gets played out in our contradictory pictures of the ageing process: on the one hand, it makes us wiser, more magnanimous, not so self-centred; on the other hand, we become crabby, small-minded and selfish. Better, therefore, to give up the illusion of a future: not only does it not exist, but it's as likely to consign us to misery as put us in clover. How bracing to be relieved of such illusions! Instead of wondering vaguely about the future, we'll focus on living well right now, not unlike the teenager at the edge of time.

And yet .... Another word for illusion is imagination, and jettisoning the future is doing away with an entire dimension of mental life. Were we to live entirely in the present, we'd be forfeiting our special human faculty to live elsewhere in our heads, to project forward in time, and to construct a fantasy life for ourselves.

Few of us may be novelists, but we all share this facility for fiction, a creative ability to fashion worlds unconstrained by the facts of the now. As we wander from this spot in time, among the infinite possibilities we can mentally conjure is one in which we are better people. Without the imagination, we'd have little concept of a new improved self, and without that concept we'd have no idea of what we were aiming at. Both involve living outside the present. What's more, such images keep us young: they hint at the many lives to live within the one life we've been given, prompting us to stay on our mettle.

A longer life, in other words, offers more opportunity for self-modernisation. The build-up of experience is also a build-up of material that can now be worked, remoulded, reconfigured in the service of the new you.

The passage of time deposits all sorts of things about ourselves we'd like to change: the longer the life, the more matter to be refashioned. What it involves is manufacturing pictures of the self created not in the factory of the present, where there's too much reality, but in the imagination, where the walls are elastic. And there's the added benefit of slowing down what strikes us, as we get older, as the accelerating character of time.

What makes time appear to go faster is the absence of events to punctuate and articulate it – a lack of variety that is more prevalent in the second than the first part of life. To furnish this second part with the activities of a new self, therefore, is to break time up into different shapes to strew across its otherwise monotonous onward, and ever faster, march. This means not only adopting the generic activities of retirement, such as gardening or travelling, but, say, rejecting your self-image as unmusical, and taking up the piano; hanging out with new people; changing your political views.

Just as longer life expectancy may result in a succession of partners and careers, so it will disrupt the notion of remaining the same person from cradle to grave. The challenge of getting older is not to age along a continuous axis that extends from where we are, but to make abrupt turns. That means becoming not only better, but different.

Robert Rowland Smith is the author of Driving with Plato (Profile) published this week