Steiner's teaching that the power behind all reproduction sits in the moon, which once worked inside the earth and now works on it from outside.
The Fructifying Principle in the Moon in Anthroposophy is Rudolf Steiner's doctrine that the force making reproduction possible resides in the moon, set out in his lecture of 3 July 1924 at Dornach, published as The Evolution of the Earth and Man and the Influence of the Stars (GA 354). Steiner described an Old Moon earth in which the moon was still lodged inside the planetary body, and reproduction happened within that one living organism. A bird-like race living in the dense sulphurous air let fall what a race of giant amphibians in the thick fluid sucked up, and what those below developed fructified those above in return. The upper world fructified the lower and the lower fructified the upper. When the moon split off into cosmic space, that mutual inner exchange ended and fructification had to arrive from outside. In German, das Befruchtungsprinzip.
The Fructifying Principle in the Moon answers a question Steiner's Goetheanum workmen had put to him directly: why does anything reproduce at all? His answer was cosmological rather than biological. Fertility is a lunar power. It once operated as an inner exchange inside a living earth that had not yet given birth to its satellite, and it now operates at a distance, on separated bodies that must seek one another out.
In Steiner's Own Words
On the other hand, to the creatures above came what was developed by those below and this again was a fructification. Reproduction was at that time of a very different nature; it went on in the whole earth-body. The upper world fructified the lower, the lower world fructified the upper. The whole earth-body was alive. One could say that the creatures below and the creatures above were like maggots in a body-where the whole body is alive and the maggots in it are alive too. It was one life, and the various beings lived in a completely living body.
What it Means Today
The claim that fertility is lunar reads as folklore until you stand on the Great Barrier Reef in late spring. In 1984 Peter Harrison, Bette Willis and colleagues at James Cook University published "Mass spawning in tropical reef corals" in Science, documenting something no one had recorded before: more than a hundred scleractinian coral species releasing eggs and sperm together, over a handful of nights, in the days following the full moon. The reef does not reproduce by pairing. It reproduces by broadcast, every colony letting go into the water column at once, with the water itself doing the joining. A 2007 Science paper on the coral Acropora millepora traced part of the timing cue to cryptochrome blue-light receptors that read moonlight directly.
Set that beside GA 354. Steiner is describing a reef-scale fertility before there were reefs: an upper race letting fall, a lower race taking up, no pairing, no partners, the whole body of the earth doing the work, until the moon departs and the process has to be conducted from outside. Thalira synthesis: the coral reef is the one place on the present earth where Steiner's older arrangement is still legible, a whole living surface fructified as a single unit on lunar cue rather than organism by organism, which is why a spawning reef reads less like a colony of separate animals than like a surviving fragment of the earth-body Steiner said we came out of.
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