Okay, so here's where Cormac McCarthy and Virginia Woolf come into play. I happen to admire both of these writers tremendously. But, what happens when we compare the two? McCarthy's Pulitzer Prize winning novel, The Road, is mostly full of showing. (For my formal definitions of showing and telling, check out yesterday's post.) In a few places we get insight into the protagonist's mind, but those moments are rare, and the action does a lot of the work. Without giving too much away, this is the story of a father, the protagonist, and son trying to survive in a harsh world. The threats and conflicts are mostly external: extreme weather, hunger, bad guys with guns. (There is one big internal struggle that I'll get to in a moment.) Virginia Woolf's To The Lighthouse, on the other hand, is mostly telling. In just the first few pages, very little action happens, and yet we get paragraph after paragraph of internal thoughts. We find out what worries the characters, what amuses them, and what they think of the other characters. Here, the conflicts are psychological.
So, who's the stronger writer? McCarthy plays by the Show-Don't-Tell rule, so that's one point for him, right? Well, the answer is that it depends on the subject matter. Virginia Woolf tells because her subject matter, the characters' myriad of thoughts, would be invisible to us in any other way. We see physical signs of thoughts, but if a man, let's call him "The Thinker" is sitting at a bench with his chin in his hand, do we know exactly what he's thinking about? If a little boy is red in the face, do we understand that he's not frustrated because he lost the soccer game but because he understood for the first time that, even when a person tries their very best, sometimes they still fail? If your goal is to illuminate the internal thoughts of multidimensional and complex characters; if, like Woolf's Mrs. Ramsay, your character has a thousand thoughts about a thousand things while she is silently altering her son's pants, then chances are, to express those thoughts, you will need to tell. McCarthy's interests in The Road lay externally. He was portraying a changing world and the thin line between good and evil. For the most part, the struggles were so basic that they didn't need to be dissected in detail. So, for him, showing was more valuable because it made us experience the subject matter he was interested in. And, for the one struggle that was internal, McCarthy ended up using many telling lines to convey it. (Sorry for the vagueness, but I don't want to ruin the story for anyone who hasn't read it.)
I think the main reason the Show-Don't-Tell rule came into existence was because it's more engaging for a reader to have to observe physical signs and interpret them to the character's emotions, and being engaging keeps the reader interested in your work. But, if your range of emotions goes beyond simple sadness or anger or fear, then telling can be equally interesting because you are illuminating subtle thoughts and emotions that the reader might never even know existed. So, the key, I think, is to be interesting and to not be so obvious as to be boring. Chances are you will want to show sometimes and tell at other times depending on what you are writing about. It's a matter of choosing the best tool for the job.