Karl Gustav Carus

Carl Gustav Carus appears in the evidence as a name attached to a theoretical history of dreaming, not as a biographical subject. The account’s central concern is how sensations arising inside the body might become dream-images: bodily activity supplies the stimulus, while the sleeping mind renders it as representations. This approach links dream formation to the body’s largely hidden life, but leaves open how any particular physical sensation determines the dream that follows.

The body as a source of dreams

The account describes the theory of organic stimulation as a particularly abundant potential source of dreams. If illness can make internal bodily sensations available as dream-stimuli, the theory proposes, organs need not first become sick for their activity to affect the sleeping mind. During sleep, attention diverted from the external world may turn inward; the separate activities of the organ systems could then provide material for dream representations.

This physiological account also offers physicians a way to connect dreams with mental disturbance. The hidden interior of the body and the obscure origin of dreams are treated as corresponding mysteries; changes in general bodily feeling and stimuli from internal organs are also invoked in explanations of psychoses. The account says this theory was proposed independently by several thinkers, situating Carus’s name within a wider discussion rather than attributing a particular argument or discovery to him.

Schopenhauer and the making of dream-images

A related line of thought is traced to Schopenhauer’s writing in 1851. On this account, daytime impressions are transformed by the intellect into a world ordered by time, space, and causality. Sensations communicated from within the organism may affect mood without being consciously noticed during the day, when external impressions drown them out. At night, once that noise subsides, the internal stimuli can come forward, like the murmur of a stream becoming audible after daytime sounds have ceased.

The intellect responds by performing its characteristic work: it turns those stimuli into figures located in space and time and connected by causality. Dream-images arise through that transformation. The theory therefore does not treat the dream as a simple copy of a bodily sensation; it describes the mind as giving bodily excitation a representational form.

The account then names Scherner and, after him, Volkelt as thinkers who pursued the relationship between bodily stimulation and dream-images further. It postpones a fuller consideration of their work to its later discussion of dream theories. Carus is not assigned a specific position in this sequence, and the evidence does not clarify whether his name signals direct influence, a parallel view, or another connection.

Competing explanations of organic influence

Krauss develops a broad version of the physiological approach, deriving dreams, hallucinations, and delusions from organically caused sensations. He allows that almost any part of the organism might become the starting point. His categories include general feeling and sensations associated with muscular, respiratory, gastric, sexual, and peripheral systems.

In Krauss’s proposed process, an awakened sensation calls up an associated imagined idea, and the sensation and idea combine into a single formation. Consciousness then attends to the accompanying idea rather than to the sensation itself. Krauss gives this transformation a special name, transubstantiation of sensations into dream-images. His account supplies a mechanism for how bodily stimuli might enter dreams, though it remains one theory among several.

The evidence distinguishes wide acceptance of organic physical stimuli as influences on dream formation from disagreement about the law governing their relation to dream content. An interpretation based on physical stimulation must try to trace a dream back to its organic cause. Yet the source may become apparent only through the dream’s own content, making the proposed cause difficult to establish independently of the interpretation.

Typical dreams and the limits of explanation

The account presents recurring dreams of falling, teeth falling out, flying, and being naked or inadequately clothed as cases for which bodily explanations had been proposed. The nakedness dream was attributed to sleeping without bedclothes. The teeth dream was linked to dental sensitivity, without requiring bad teeth. Strümpell explained flying through the rise and fall of the lungs and the loss of conscious awareness of sensations in the chest; he explained falling through changes in pressure felt on the skin when an arm sank or a bent knee straightened.

The account acknowledges the plausibility of these explanations but identifies a methodological weakness: they do not provide independent grounds for deciding which organic sensations disappear from awareness or force themselves upon it. Instead, the explanation can seem to arrange bodily sensations until a pattern favorable to the proposed dream-image emerges. The discussion promises to return to typical dreams and their genesis, leaving the issue open at this point.

M. Simon offers two further rules. If an organic system involved in expressing an emotion is aroused during sleep by another cause, the resulting dream is expected to contain imagined ideas appropriate to that emotion. If an organ system is active or disturbed, the dream is expected to introduce ideas connected with the function it performs. Together these proposals show the range of attempts to specify how bodily activity shapes dreams, while underscoring the larger problem: the evidence does not settle a single rule that accounts for the relation between physical stimulus and dream-image.