Not content with Facebooking our every foible, Instagramming the births of our children and live-tweeting our daily lives, more and more of us are now making a public spectacle of dying. We’re inviting strangers not merely to ‘like’ expertly filtered photos of our breakfasts, but to admire the way we peg out. Nothing better captures the death of privacy than this publicisation of death.

It began with the literary set. It’s a rare writer these days diagnosed with a terminal illness who doesn’t get a book out of it. Jenny Diski is the latest public dyer. She’s giving readers of the London Review of Books a blow-by-blow account of her death by lung cancer, covering everything from the diagnosis to her chemo sessions. It’s moving and sometimes gripping, but it feels wrong.

To draw back the curtain on a woman’s death scene and watch her skin turn ‘deep red with flaky patches’ — shouldn’t that be for friends and family, not for strangers? Even Diski seems to have doubts. ‘Another fucking cancer column’ is how she refers to it. She follows on from Christopher Hitchens, usually the scourge of fashionable hoohah, and Iain Banks, who set up a website where fans could read updates on his cancer and even sign a guestbook: a kind of pre-death condolence book which soon filled up with mawkish expressions of sorrow. On the site, Banks’s wife was referred to as his ‘widow-in-waiting’.

In the late 1990s and early 2000s, John Diamond’s cancer column in the Times was widely praised and eventually turned into a play: A Lump in My Throat. Ruth Picardie’s cancer column for the Observer — six pieces in which she graphically detailed her decline — became a bestselling book: Before I Say Goodbye. The actress Sheridan Smith has just appeared in a BBC Sunday-night adaptation of The C Word, the memoir of Lisa Lynch, who died from breast cancer in 2013.

Dying is now such a major publishing sell that it can bring a writer the kind of fame he or she only dreamt of when healthy. The Guardian drily noted this in its obit for Diamond: ‘It was a horrible irony that the illness that eventually ended [his] life was also, professionally, the making of him.’ Or consider this desperately sad headline to a blog in the San Francisco Chronicle, written by a young woman who died from skin cancer in 2010: ‘Cancer. Despair. And now, a blog.’

When Kate Granger, a young British doctor, was diagnosed with cancer in 2011, she promised to live-tweet her death. Her number of Twitter followers exploded into the tens of thousands. Were they sympathisers or ghouls? Granger used the hashtag #deathbedlive, which somehow says it all.

In one of her ‘fucking cancer columns’, Diski said: ‘I have no choice but to perform and to be embarrassed to death.’ But is this really true? And where does this compulsion to ‘perform’ come from? I think, in part, it’s peer pressure. It’s so entrenched now that we must ‘share’ everything that to refuse to offer up your misery for the entertainment of strangers is to be considered weird. A whole subsection of psychobabble has been invented to castigate those who don’t open up: they’re in denial. They’re bottling things up. To stay strong, to keep things private, is madness; to photograph and describe and tweet your physical and mental malaises is sanity.

The pornography of death is the logical conclusion to the oversharing of the 21st century, which is packed with madness memoirs, anorexia columns, child-abuse chronicles — and the justification is always the same. It’s about ‘raising awareness’ or ‘breaking the final taboo’ (the one surrounding death).

I don’t buy it. These are fancy terms for emotional incontinence. Some things are taboo for a reason. Our forebears kept quiet about the details of their decay not because they were scared or stupid, but because they recognised that something sacred is lost if we make them public. Death is a time for saying goodbye to those you truly love, for settling your affairs. Death requires quiet, contemplation, distance from the fussy, nosy world of public life. Invite strangers into this moment and you change it utterly.

The other reason for all the public dying is more troubling than peer pressure. People live their lives online now, seeking affirmation for their every move in the form of ‘likes’ and ‘retweets’ and so on. To a 21st-century social media addict, an experience isn’t real or valuable unless it’s witnessed and approved of by strangers. Everything is observed. Everything is entertainment. Even death.