To mark the publication of my new book and the School of Life Live tour, here’s another one of the columns I write for the BBC’s international site, BBC Future – exploring the curious paradox of forgetfulness in a digital age.

“Without forgetting it is quite impossible to live at all.”

Wise words from Friedrich Nietzsche in 1874. Nietzsche understood that too great a weight of history can squeeze the life out of the present; and when it comes to forgetting in 2012, the internet is the increasingly weighty elephant in every room.

Whether on search engines, social networks, blogs or email, there is now an online record of almost everything we’ve thought, said, seen and done – or wish we hadn’t. Whether we like it or not, we seem to be creeping ever closer towards Nietzsche’s nightmare: a world where that “gravedigger of the present,” the past, is quite literally unforgettable.

Or are we? For what really interests me is not online record-keeping as such – but what the very process of creating a digital record can erase under the cover of preservation. And there’s one class of experience above all in this category: the process by which we arrive at words and ideas in the first place.

Earlier this year, I visited the Tate Modern in London to see a retrospective exhibition about the life and work of the conceptual artist Yayoi Kusama. Over the course of the exhibition, I was struck by both the chameleonic progression of her art and the gathered physical records of her dealings with friends, mentors, galleries and fellow artists. There, behind glass, were letters she had sent as a fiercely ambitious young Japanese painter to European and American galleries, complete with hand-written corrections and adornments. And there, too, were the largely guileless requests of her later correspondents, asking for paintings, favours, advice and inspiration, all also amended by hand.

Artists born today will assuredly enjoy retrospectives far richer in digital records than anything we could conjure for someone born even in 1979, let alone 1929, as Kusama was. Yet the kind of correspondence I viewed behind glass in the Tate is already a thing of the past, together with the history it embodies: a history of typed first drafts, penned second thoughts, doodled margins, and rarely enough time for further reconsiderations.

Even reading a piece of writing like this column, onscreen, the process of composition is entirely erased from history. The author’s hand – one of which is typing out these particular words on the screen of a computer just outside London, and which will later be correcting them in black ink on a printout – is notable only by its absence.

If this still seems like a minor omission, consider a story told by MIT professor Sherry Turkle in her 2011 book Alone Together. Among school and college students, Turkle notes the not uncommon practice of one “expert” individual being tasked with writing important text messages on behalf of less gifted peers. Someone wishing to flirt by text, for example, might delegate the precious task to their most textually talented acquaintance; or, at the least, might spend many hours composing and revising the perfect 140-character communication.

Not only is nothing of this process visible in the final product; its very invisibility and impersonality are a large part of the point of the product itself. For what matters most of in social media is the performance in which text messages, status updates, emails and images all play their part. It is, like all good performances, at least as much about selectivity and artistry as honest self-exposure.

It’s a strange paradox that our human twitches and hesitations leave almost no marks within a medium whose greatest claims combine immediacy with permanence. And it’s a situation that is all the more troubling for its near-invisibility

Nobody has ever expected a letter, a book or a painting to tell the whole truth. When it comes to the central question of social media, however – “what are you doing?” – we are likely to treat the answer as an unvarnished insight into someone else’s life.

It’s easy to get carried away with such conclusions, and talk about “bad” technologies and the vices they breed. Yet this helps no-one, and misses the point. The question isn’t whether we can come up with a perfect system of outsourced remembrance. It’s how we can best live with the tools we’ve got: a process that must begin with becoming aware of their limitations (and ours) in the first place.

As Nietzsche knew very well, neither human memories nor intentions are entirely to be trusted. Or – as Mark Twain, another great man of his times, put it – “when I was younger, I could remember anything, whether it had happened or not.”

If we can bring a little more scepticism to bear on the polished appearances we encounter online – and, perhaps, become a little less eager to burnish the way we appear to others – we may yet master the art of forgetting just enough.