Riddles of Soul and Body gathers the public lectures Rudolf Steiner delivered in Berlin during March 1917, a cycle of seven addresses catalogued in his collected works as GA 66. The talks, given at the height of the First World War to general audiences rather than to members of his esoteric school, take up a single stubborn question: how does the human soul stand in relation to the human body? Steiner frames it as the meeting point of two riddles that the science of his day had pulled apart, the riddle of inner experience and the riddle of the physical organism. Across the cycle he argues that neither academic psychology nor laboratory physiology could bridge the two, and he offers spiritual science as the missing bridge. This guide surveys what the volume contains and why it still repays careful reading, without reproducing Steiner's own text.
Place in Steiner's Work
By 1917 Steiner had spent more than a decade building anthroposophy as a path of knowledge, but this cycle belongs to a specific and consequential moment. In the very same period he was completing his book Von Seelenrätseln, the work in which he first stated in print his doctrine of the threefold human organism: the nerve-sense system, the rhythmic system, and the metabolic-limb system. GA 66 is where that account was worked out in front of a listening public. The lectures show Steiner in dialogue with the natural scientists he most respected, quoting the physiological psychology of Theodor Ziehen and the biology of Ernst Haeckel's school, and pressing exactly where their methods stopped short.
The volume therefore sits at a hinge in his output. Behind it lie the epistemological books of the 1890s and the earlier lecture cycles on the human being's supersensible members. Ahead of it lie the practical applications of the threefold idea in medicine, education, and curative work through the 1920s. Read in sequence, GA 66 is the place where a philosophical intuition about soul and body hardens into a specific physiological claim that would shape everything Steiner built afterward.
The wartime setting matters as well. These lectures were given to a Berlin public living through the third winter of a catastrophic war, and Steiner did not treat the question of soul and body as a purely academic exercise. The reduction of the human being to a nerve mechanism was, for him, part of a broader crisis of thinking that had material consequences for how people understood freedom, responsibility, and death. That urgency gives the cycle a tone quite different from a laboratory report. Steiner is asking his listeners to notice what a whole civilization loses when it can no longer locate the will inside its own picture of the human being.
Themes and Structure
The seven lectures circle one problem from several sides, and it helps to read them as movements rather than as separate essays. Steiner opens by describing a failure of communication: the soul researcher and the natural scientist, he says, speak two different languages and no longer understand each other when they turn to the human being. His diagnosis is that both camps misapply otherwise sound concepts, taking an idea that is correct in one setting and forcing it onto a reality it does not fit.
From there the cycle turns to the nervous system, and this is the argument for which the volume is best remembered. Steiner examines the reigning picture in which thinking, feeling, and willing are all traced to nerve processes. He grants that the science of mental representation is impressive, then shows how it quietly loses first feeling and then will. In his reading of Ziehen, feeling is demoted to a mere tone attached to representations, and the will is dropped altogether because no nerve mechanism for it can be found. As Steiner puts it, "The will, therefore, is simply eliminated by Ziehen."
Against this, Steiner advances his own correction. He argues that the so-called motor nerves have been misinterpreted, that the nervous system does not generate the will at all but serves the inner perception of our own movement and intention. On the standard view, a nerve carries a command outward and the muscle obeys, so that the will appears to be a link in a mechanical chain. Steiner reverses the reading. In his account those same nerves are sensory in function even when they run to the limbs, allowing us to feel and register the movement we are carrying out. Willing itself reaches into the body through the metabolic and limb activity, not through nerves that push muscles like levers. The consequence is important: if the nervous system does not manufacture the will, then the will cannot be explained away simply because no nerve for it can be found.
This is where the threefold reading of the organism does its work. Thinking rests on the nerve-sense pole, willing on the metabolic-limb pole, and feeling lives in the rhythmic middle where breath and heartbeat mediate between the two. Each soul activity, in other words, has a bodily home, but not the same one, and the mistake of the physiology Steiner criticizes is to look for all three in the nerves alone. Once the map is corrected, the disappearance of feeling and will from the scientific account stops looking like a discovery about the soul and starts looking like an artifact of where the researcher chose to look.
The later lectures widen the frame to immortality, destiny, and the human life course, connecting the small riddle of nerve and muscle to the large riddle of what in the human being outlasts the body. Steiner also uses these talks to settle scores with the fashionable materialism of his era, recounting how figures in Haeckel's own circle had begun quietly retreating from the strict Darwinian chance-theory they once defended. The point is not merely historical. It lets him argue that the frontier of honest science was already moving toward the spiritual questions his listeners cared about.
Throughout, Steiner's method is worth noticing. He does not dismiss the science he cites; he admires it and then asks it to broaden its concepts rather than abandon them. The structure of the cycle mirrors that stance, moving from respectful summary of contemporary research toward a proposal for extending it.
Glossary Terms from this Volume
The following entry in the Thalira glossary draws directly on this volume. Follow it for a focused treatment of the idea and its sources.
Where to Read It
You can read the full lectures of GA 66 in translation at the Rudolf Steiner Archive, which hosts the source texts online at rsarchive.org. Several of these Berlin lectures appear there under individual English titles, including "The Human Soul and the Human Body" and "Mind and Matter, Life and Death." For print and ebook editions, search the publisher catalogue at SteinerBooks, where the volume and related collections are listed.
Continue Your Study
If this volume interests you, a few next steps will deepen the picture.
- Browse the full Thalira glossary to see how the will, the nerve-sense system, and the threefold human being connect to Steiner's wider vocabulary.
- Read the dedicated entry on Motor Nerves and the Will for the specific claim at the heart of this cycle.
- Return to the GA Work Library to trace how the threefold idea developed across Steiner's later medical and educational lectures.