We are always either drawing closer or drifting apart — there is no stasis in relationships. The direction of movement may change over the course of a relationship, but there is no stasis. Despite our culture’s bias for the drama of cataclysm — the violent heartbreaks, the very notion of falling in love, implying a sudden tripping along the path of life — the most profound of these motions of the soul are the work of gradualism, their pace geologic, their velocity that of continents, so incremental as to be imperceptible, until one day two people find themselves a sum greater than its parts: infinity, or zero.

This elemental tendency comes to life with great levity and charm in Drew Beckmeyer’s picture-book Stalactite & Stalagmite: A Big Tale from a Little Cave (public library). The tale is big because its theme is the largest of feelings, but also because tucked into the love story is the evolutionary history of how our rocky planet became a living world — something I especially appreciate as a kindred practitioner of Trojan-horsing science into life through love.

Just like those who have lived a long love become each other’s memory-keepers, Stalactite and Stalagmite pass the time by recounting their shared memories of bygone eras and extinct creatures: their first visitor, a trilobite — one of the earliest arthropods, who told them tales of life at the bottom of the deep sea; the thirsty giant ground sloth who licked them for every precious drop and casually informed them about the evolution of fur; the immense triceratops who made the whole cave tremble with the echo of his roar; the meteors that turned the sky black and lashed the Earth with acid rain so that for a long while nothing could grow and thrive.

Stalactite bonds with the bat over having the same vantage on the cave, and Stalagmite snuggles with the ichthyostega — one of the first walkers of the land, who tells the story of how fish grew legs.

Stalactite and Stalagmite were there, inching closer still together, when we came onto the scene to draw our dreams and myths and fears on the cave wall, to invent fire and language and science, so that one day tour guides could shine flashlights onto the cavernous darkness and tell children how stalactites and stalagmites form.

The formation of that “something new” is what Adrienne Rich meant when she wrote of love as “a process, delicate, violent, often terrifying to both persons involved.” What terrifies us most is the fear that the new formation might be a merging so total and irrevocable that we lose ourselves in the other, lose every last boundary of where one ends and the other begins, fall prey to the self-abandonment many mistake for love.

Overhearing the tour guide, Stalactite and Stalagmite reflect on their destiny, facing that fundamental fear but regarding the new formation with the awareness, honed on eons of observing change, that we never really know what lies on the other side of a transformation — we can only envision what we lose of the past we know, but not the future we stand to gain.

The key, in love as in evolution, is not to mistake the limits of the imaginable for the limits of the possible.