Gardner sums up this chapter (the first chapter of part 2 of On Moral Fiction) this way:
"Real art creates myths a society can live instead of die by, and clearly our society is in need of such myths. What I claim is that such myths are not mere hopeful fairy tales but the products of careful and disciplined thought; that a properly built myth is worthy of belief, at least tentatively; that working at art is a moral act; that a work of art is a moral example; and that false art can be known for what it is if one remembers the rules. The black abyss stirs a certain fascination, admittedly, or we would not pay so many artists so much money to keep staring at it. But the black abyss is merely life as it is or as it soon may become, and staring at it does nothing, merely confirms that it is there. It seems to me time that artists start taking that fact as pretty thoroughly established."
I keep looking back at the original publication date of the book, because I find it hard to believe that it was written in the late 1970s. Nothing much seems to have changed . . . Of course what he says about good art, about moral art, if true at all will be always true. But what he says about the bad art of the '70s strikes me as not essentially different from what we still see today. So many of my students still think that a "happy ending" of any sort is inevitably "cheesy" and "unrealistic" because all that is "real" is evil and despair. And my students are Christians, young folk who profess to believe in the ultimate happy ending . . .
Of course, what Gardner writes about here is why The Lord of the Rings resonates so truly. But one needn't write literally mythic fiction to write "myths to live by"; realistic fiction, any genre of fiction, non-fiction, drama, poetry . . . any form of art can create a myth to live by. A student of mine once wrote a short story about a boy (a painter) and a girl (a writer) who are spirited away to another world where their stories and paintings come true: what they envision becomes the reality of that world. Ever since, I have considered all that I write as containing a vision which I pray may come to fruit in someone's life.