I've been involved in critique groups since I was twelve. I've critiqued and been critiqued; I've organized critique groups. I've been in classes that worked and classes that didn't, and it's my opinion that where critique works best is where there's a certain degree of argument on the part of the author. But it has to be the right kind of argument.
First let's cover the wrong kind, since it's easier (and funnier) and you've probably been on the receiving end. (Maybe, if you care to admit it, you've done it yourself.)
Nonproductive arguing is when someone points out a flaw in your manuscript, and you fire back with, "Okay, you may feel that way, but that's not what it's really like. I meant to do that. This wasn't a problem for anyone else, and I think it's perfectly fine."
Do that and I guarantee you two things. First that your manuscript won't improve, and secondly that you'll be beating the pavement looking for another beta-reader.
The sad fact is that just because you intended to do something (and even worked hard at it) doesn't mean it works in your manuscript. I've been on the other end of that kind of defensive critiquing, and when I realized 45 minutes of our critique session's hour were taken up with this writer defending the work rather than listening to the criticisms, I shifted to a position of "State it once and then let the writer blow steam at me." Shortly thereafter, I left the group.
But there's a productive way to argue with your critique, and it's not to defend. It's to let the work defend itself.
First, while you're receiving your critique, make sure you stay utterly quiet. You take notes, or if it's over email, you just read. You get the whole thing in without responding. (Mary has suggested putting the critique in the freezer.) You judge for yourself whether this person is working to make your piece better and if you're a good match for one another. Assuming both are true, you can then proceed to argue.
And you do that without the person in the room. You sit in front of your manuscript and you look at the changes this person wants you to make, and you ask yourself how the manuscript itself responds to this particular criticism.
Why yes, I was the woman sitting at her computer desk yelling at the marked-up manuscript, "Are you blind? Were you reading the same story I was? Because that information is in there!" But in order to do that, I had to make sure the information really was in there. Sometimes you discover mid-holler that it's not. (Oops. And then won't you be glad you didn't argue in public?)
It's the same with comments about character, setting, dialogue: listen to the criticism. Evaluate the manuscript and let the manuscript defend itself. If the manuscript can't, tackle the change, even if you don't change it in precisely the suggested fashion.
Whenever I edit for someone, I send them a caveat: that their ideal response is not to say "Yes, ma'am" and make every change I suggest. I'd much rather they say, "Jane, you are full of hooey, and if you'll look at the manuscript, you'll note the following reason why." Or even better, "Yes, that's a problem, but I have a better way to fix it." That way, the writer fully owns her own manuscript.
Three days ago, while responding to my agent's comments on one of my manuscripts, I started replying to one suggestion in the negative. She has a razor-sharp editorial mind. She'd pointed out an unfortunately large "expository lump" and said it needed to be broken down, and possibly moved. In my email, I started typing something like this:
Yes, I understand this is a lot of exposition, but it has to be in the manuscript by this point so the reader understands what happens on the next page. If it's moved, it would have to be earlier rather than later, and I can't think of anywhere we'd move it to. The only possible way to do it would be to put this information in the dialogue of--That is the point at which I highlighted my entire response and deleted it. I went into the manuscript, cut the expository lump, and went back into the opening scene to put it in the mouth of that character; the character not only presented the information but also gave us a much better understanding of his personality in the process. The manuscript is improved in multiple ways, and only because I "argued" with my critic.
And in arguing, realized she was right.
Go ahead and argue. Just make sure you argue effectively.
Jane Lebak is the author of The Guardian (Thomas Nelson, 1994), Seven Archangels: Annihilation (Double-Edged Publishing, 2008) and The Boys Upstairs (MuseItUp, 2010). At Seven Angels, Four Kids, One Family, she blogs about what happens when a distracted daydreamer and a gamer geek attempt to raise four children. She is represented by the riveting Roseanne Wells of the Marianne Strong Literary Agency.