The shared soul and I of a whole animal species, living on the astral plane, of which the single animals are extended members.
A Group Soul is the being that an entire animal species shares in common, in place of the individual I that each human being carries. Steiner describes the lion, the wolf, the bee as belonging together to one group-soul or group-ego, a real personality met on the astral plane. The many animals on earth are its limbs reaching down into the visible world, while the soul itself stays behind the veil.
A group soul in Anthroposophy is the common soul-and-I that a whole animal species shares on the astral plane, rather than each animal carrying an individual ego the way a human being does. Rudolf Steiner sets this out in The Influence of Spiritual Beings upon Man (GA 102, 1908): the lion-species, the tiger-species and every other animal kind belong together to one group-soul or group-ego, a real supersensible being whom clairvoyant vision meets on the astral plane as a distinct personality. The single animals on earth are its extended members, like ten fingers reaching through a curtain while the being itself stays behind the partition. The human folk-soul is the nearest analogue one step up. Today the idea reconnects with Goethean zoology, where the species is read as a living archetype, not a mere class label.
In Steiner's Own Words
You have seen that groups of animals of the same species together belong to a group-soul or group-ego and that on the astral plane we come upon the lion-soul, the tiger-soul, and so on, as independent personalities whom we can meet there as we meet the human being on the physical plane. We saw in this way that in these higher worlds we meet with certain beings who, so to speak, extend part of their organism, their separate members, down into the physical plane. If a man were to extend his fingers through openings in a curtain or partition we should only see the ten fingers, the man himself would be behind the partition. So it is with the group-egos of the animals.
What it Means Today
The group soul reads strangely until you set it beside the human individual I. A person says "I" to themselves and means a single self that incarnates once, here, behind one face. An animal cannot do this. For Steiner the wolf or the herring is not a self-standing ego at all but a member of its species-being, which holds the I one plane higher up. The folk-soul is the bridge case: a people shares a Volksseele much as a species shares its group-soul, except the human folk-soul leaves the individual I free underneath it, where the animal group-ego does not.
The cleanest modern footing for this is Goethean zoology. In his comparative morphology of the 1790s, after locating the human intermaxillary bone in 1784, Goethe treated each animal kind as a living archetype, a Typus that the single specimens vary but never exhaust. Steiner edited exactly these morphological writings for the Kürschner Deutsche National-Litteratur edition between 1883 and 1897, and his group-soul is that idea pressed one step further: the type Goethe read off the skeletons is, for the clairvoyant, an actual being on the astral plane. To work with it Goethean-style is to observe a whole kingdom, watch the lion-nature or the cattle-nature express itself across many individuals, and treat the species as one character rather than a label pinned on a heap of organisms. Each species is guided by a group-soul; the birds reveal this most clearly in the bird world. A group-soul guides each species; far above, the group-souls of the stars ensoul whole constellations.
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