The consensus, at least as I have seen it, is that the vagueness allows the fairy tale to take place at all times and any time, making it accessible to all people throughout the ages.
It also shows that the "once" and the "time" of the story are parallel places and times, a fantasy world where we are asked to suspend our disbelief and play along with the magical, absurd, and pure evil things that can and do happen.
The idyllic pastoral way of life depicted fancifully in fairy tales is hard to pinpoint historically, though research like scholar Ronald Hutton's shows that some aspects of Merrie England did exist before Puritanism.
While "real" life--as opposed to reality in fairy tales--is far more complex (those that mean us harm are not clearly ugly; goodness does not shine through a benefactor; and justice is never quite as satisfying), fairy tales distill truths about our living world.
Skeptics scoff to call anything magical, but what is the birth of a child? In this context, the word "magical" falls way short of the mark. So in fairy tales, a train of fairies and angels attend a baby's christening.
Trees die and drop their leaves in the fall but resurrect in the spring, when blossoms appear on their branches. So in fairy tales precious gems grow on trees and gardens bloom overnight.
Men kill other men without reason, and through violence and disease our loved ones are robbed from us before their time. So in fairy tales, hideous trolls live under bridges and obstinately block the way, frustrating the crucial journey.
But I believe in the Merrie England of fairy tales in yet another way. Its no-time-but-any-time-and-all-time suggests there is reality outside our senses. If it isn't historical it is because it transcends history. Something of this effect is tackled by Charles Williams in his Arthurian cycle, in which a Utopian Logres peaks for a time as part of a larger empire. In The Lord of the Rings, the wisest and saddest of characters are always looking West, either for a sunken Atlantis or Blessed Realm with fragile ties to the physical world.
|Boucher, Shepherd piping to a Shepherdess|
Merrie England stirs in us two things: (1) the idea that common and everyday occurrences have deeper meanings and (2) that the reason we are restless is because there is an ideal world (whether it existed or not, whether it can be achieved or not) for which our hearts ache.