Alex Clark, writer and literary critic

We're both committed readers, so we should probably stick together rather than picking a fight. But this funny business of the Hawking Index, a lighthearted attempt to work out how far people persist in reading books, as indicated by the passages they highlight on their Kindles, has got me thinking. And it's made me realise that my view has changed. I used to believe that if you really weren't enjoying a book, you should toss it to one side and move on to something you might find more rewarding; essentially, it was born of an insurmountable fear of the sheer number of books I wouldn't get round to reading before I died.

But things have changed. Clearly, I've got older and realised that I was a fool to see world literature as a mountain I had to scale, but more to the point, I've seen the threat that endless distractions and a wussy, don't-like-it, bring-me-another attitude poses to our reading culture. I know I risk sounding po-faced, but the best books are a medium of thick description, painstakingly built word by word to produce strange and unexpected effects in the brain and heart; they deserve more than being treated like a passing bit of entertainment that hasn't quite lived up to the reader's exacting standards.

Tom Lamont, Observer writer

How do you expect to scale the world-literature mountain with a defeatist attitude like that? Look out for me, waving and popping a bottle of fizz, at the summit!

No: I'm not a clock-watching completist in too much of a hurry to give each book I start a fair chance. But of course you should stop reading when the fireworks aren't there. When you aren't impressed, lulled, entertained, lightened, depressed, remoulded, whatever you go to books for. Even if it means reshelving the thing with that telltale halt in the creases on the spine, or admitting to friends, spouses or book clubs that you've bunked a recommendation.

Alex, you speak as if the very fact of a book's publication, of it having adverts on the train, or chummy cover quotes, ensures quality. Like hell. All sorts of humdrum, one-draft, low-horizon filler gets released – gets pushed, gets bought, gets warmly reviewed, even. So be your own filter. A good time to abandon, I think, is when the peal from your in-built bullshit alarm gets too loud to ignore; if you want to do it by numbers, stop when you begin to groan at a rate of more than once per page. At that point do say: "I-don't-like-it, bring-me-another." Stop at once, mid-sentence if necessary, and throw that book into the sea.

AC Believe me, I am not defending every book that gets published, nor telling people to force themselves onwards when something is clearly a) dross or b) so completely antithetical to everything they as a reader hold dear that only misery awaits. That would be ludicrous, masochistic and likely to result in a more total disenchantment with reading. (By the way: do let's reconvene for a debate about the state of publishing and of the importance of high-quality review coverage another time.)

But I am saying that if you give up on a book the minute you don't like a character, twig a plot development, see quite where the author's going with it all, have a sudden yen for a game of Candy Crush – then you're going to miss out. I've nothing against reads that are quick and dirty fun, but seriously good books are immersive experiences, demanding of time and patience. Respect them.

TL But there is a masochistic sense out there – isn't there? – that it's somehow bad form or disrespectful or helpful to Hitler not to finish books. Very austere, very British. Very clear your plate.

Every time I go on holiday, I see first hand the futility of the soldier-on approach. My wife will push through a book she doesn't love (and soon doesn't like and soon palely loathes) making ever slower progress – and so the week vanishes. Meanwhile, I'm sprawled under a pile of discards, hurling about Updikes and Hazzards and le Carrés, all fine, all good, but not the novel I'm looking for, the one that climbs inside my head and eats out a hollow and uses the space to riverdance.

Humour me. I bet there are times, recently, when you wish you'd ditched.

AC Yes, of course there are and I've done it!

TL Name names.

AC Sorry, no names, no pack drill: given last week's reports about how little authors are earning, they don't need another kick in the teeth from me.

But the image of your holiday is exactly what I'm talking about: the idea of you like some Roman emperor, your thumb hovering over these peerless works of prose, poised for the downward jerk if your every whim isn't satisfied. Get over yourself! I'm slapping a literary restraining order on you: don't get within 50 feet of a Shirley Hazzard until you've had a long hard look at yourself.

Meanwhile, I simply produce my (admittedly subjective) experience of reading the final chapters of The Goldfinch. I had been gripped throughout, but nothing prepared me for the hallucinatory, mind-bending brilliance of its finale, truly one of the great moments of my reading life. Now, in a long and complex novel like that – or Don Quixote, or Roberto Bolaño's 2666, or, for example, in one of the twisty, red herring-strewn books by my beloved Nicola Barker – there are bound to be longueurs and bafflements, moments when you think, can I? You know what? You can. And you should.

TL It's art. It's personal. You're fully entitled to be a Roman emperor, condemning or championing, devouring or exiling. I'm still sore about a recent effort to get my friends to read a Penelope Fitzgerald, Human Voices. I loved this weird, scampering novella and brought it to them expecting to be credited with a major find. They hated it, all of them. Found the book irritating, tedious, twee, none getting beyond a dozen pages.

No work is "peerless" to everybody. And it's exactly the sense that we should find something peerless, because of a reputation, because of popular opinion, that tends to keep people death-marching through books that are wrong for them.

I know plenty of smart, literate people who couldn't get on with that widely ratified classic of our time, Wolf Hall, and binned it. Good for them. So Thomas Cromwell never got anywhere near Cardinal Wolsey, let alone Henry VIII, forever remaining a teenager getting beaten up on his father's shop floor. So they opted out of the deftness, the wit of Mantell in her prime. It didn't work for them, at bone level, at gut level, and they put back the book. Shouted: "Next!" They were right to.