And so The Snow Queen also became a story about the need to seek equilibrium, in our own lives, with the natural world, even within the universe at large.

The ecosystem of our world is a closed system: it would run out of gas, collapse of its own weight.

The mers were also designed to reproduce only at long intervals, in order to maintain the natural balance of the environment in which they were placed.

The natural world is not indestructible.

The futures and ultimate fates of the characters in The Snow Queen are profoundly changed by choices made in their own minds or hearts, as well as choices unexpectedly forced on them by things beyond their control.

Animals can adapt to problems and make inventions, but often no faster than natural selection can do its work - the world acts as its own simulator in the case of natural selection.