One of the boggiest areas of literary, writerly, teacherly and studently debate is this thorny business of subjective and objective judgement. (Is there such a plant as a bog-thorn? If it's not in Cold Comfort Farm, at least, it jolly well ought to be).
On one hand, it's often the worst writers who cling to the notion that 'it's all subjective' and 'anyone's view is as good as anyone else's', in the face of a slew of feedback which all points the same way: towards the fact that just about everyone of experienced judgement thinks their writing isn't good enough. They are often the writers who have yet to learn to be bad: who simply have no internal criteria for good and bad writing, combined with no capacity to step outside their writing and read it as others do. And when friends comfort them, it's also in terms of 'What do they know, these editors?'.
In fact, as you can tell if you look at the marking scheme of a well-structured creative writing course, it's not impossible to work out some criteria for assessing writing which is reasonably objective, in the sense that most teachers would agree on the grades for most work, and that includes work which they, personally, wouldn't enjoy as reading-matter. Of course, if you want to argue that the whole literary world conforms to a particular set of tastes which aren't the whole truth, you can. You might even be right, but I think you should allow it to cross your mind that the reason your work keeps getting rejected just might because it isn't good enough. Yet.
On the other hand, we take winning a prize as some sort of objective accolade, but which of a Booker shortlist is going to win must be a highly subjective decision. How do you rate the technical merit of a pitch-perfect novella of crystal clear prose against a vast, sprawling epic stuffed with baroque riches, let alone its artistic impression when most of us have a bias of personal taste towards one end of the spectrum or the other, however hard we try to overcome it? Which isn't to say that the winner doesn't deserve to win, only that with a different set of equally good criteria, or a different set of judges, on a different day, another book of the shortlist could have won. And if I do ever win a literary prize (and I'm not holding my breath) you can remind me I said that.
Some of it depends what you mean by good but, fundamentally, our reaction to any book is an almost inextricable mixture of subjective and objective. We all know a book which is original, well written, well plotted, well-everythinged, and failed, ultimately, to set our hearts or minds whirring. But it moved our best friend to gasps of intellectual and emotional delight. And we all have books which by all those standards aren't necessarily well done, but somehow speak to us for reasons to do with our own history and sensibility, while to the same friend their technical shortcomings are unredeemed. One reader's heartbreaking work of staggering genius is another's emotionally manipulative horror, but that must be as much to do with those two readers as it is with the book, and the more cynical reaction is by no means automatically the 'right' or more sophisticated one. For example, I have a particular, personal loathing for that identification of Catholicism and poshness with glamour which you find in Brideshead Revisited and I was delighted to discover recently that Waugh himself later described it as 'an embarrassment'. But it seems to me now that it is a good book (if not a great book) by objective measures of craft and art. And while we're in the territory of last-summer-before-the-War, I enjoyed McEwan's Atonement a lot when I read it, but once I'd come out from under the spell that any good read casts, I began to feel that it's deeply flawed in both structure and writing, and in discussing it in my PhD found myself getting positively cross with it. And there's a feedback loop going on: my first subjective reaction was pleasure, by my objective objections have now coloured my subjective reactions, so that I re-read a good deal of it for my PhD without much pleasure at all.
Something which muddies the bog-pool even more is that the very first response to anything you read is a-rational. Like an out-of-tune note setting your aural teeth on edge, or the most exquisite, soaring tune lifting your heart, it's a millisecond, at least, before you know in any conscious sense what's wrong, or right. But when you start trying to find reasons for that reaction, it may not or may not be the 'real' reason. You don't like a book: you find it uncompelling and the handling of point-of-view and voice is incompetent. Do you find it uncompelling because the incompetence stops you caring about the characters, or blurs the working out of the ideas? Or is it because you don't like the characters, or can't follow the ideas, that you try to work out why you're uncompelled, and conclude it's the point-of-view problems? Perhaps in another book where these technical things aren't well-handled either, you nonetheless enjoy the whole: you took to the characters, or the ideas, enough not to notice or not to care.
The soi-disant objectivity of the one-star Amazon review "Jane Eyre is the worst book ever written" (as opposed to the honestly subjective, "I hated this book") merely suggests that pure subjectivity has its limitations as a way of understanding and enjoying literature. And we've all read highly analytical reviews which, in essence, have much the same nature. Particularly in the latter, "I hated this book" is apt to be "explained" by or cloaked in quasi-objective reasons, about how slowly the plot moves, or that the author is unfair to a character, or that the plot is old fashioned. Those may all be true, but the reviewer was alerted to them by an pre-rational reaction, and as I've suggested, that reaction may not actually spring from those failings.
But we can to some degree train our pre-rationality: our intuition. If you're lucky, the Shakespeare you found baffling and boring can be elucidate by a good teacher and then you're enfranchised in that world forever. I sometimes teach people who've never done a writing class before, but have written a novel. Their writing comes, as it were, from an entirely intuitive, subjective sensibility formed by reading. I talk about some basics - showing and telling, point-of-view and psychic distance - and then we look at everyone's work. And as we talk about what works and what doesn't and why, using these basic (and relatively though not entirely objective) ideas, their pre-rational reactions to their own work begin to change, in a virtuous (I hope) readerly-writerly-readerly feedback spiral. Do enough of this kind of work and you hit an ugly duckling stage as a reader, where you're uncomfortably aware of the technical side: you've left your readerly Eden. Eventually, of course, you recapture that capacity to read for pleasure, but the wiring along which those first a-rational reactions runs now includes not only whether a character is likeable, or whether an idea is fascinating, but whether the techniques taste good: we have, if you like, trained our intuition, our pre-rationality to objective as well as subjective things.
Maybe that's why it's so hard to separate subjective and objective reactions, though examiners, judges and reviewers, at least, must try to do so. Like everything else to do with creative work, you can untwist your reactions from each other and try to understand their origins, but as soon as you let go of the discussion, they coil themselves back together again, into a human whole.