Medical Materialism, as it reverberates through the depth-psychology corpus, names the systematic reduction of psychic, spiritual, and experiential phenomena to their organic substrates—a reduction that, once made, is presumed to settle questions of value, validity, and meaning. William James, who coined the phrase, mounts the foundational challenge: the genetic fallacy of explaining away religious experience by locating it in nerves, sexuality, or torpid livers, he terms ‘medical materialism,’ and he dismantles it by insisting that organic origin is irrelevant to the worth of a mental state. Jung extends the critique inward: medicine’s materialistic prejudice—that psychic disturbance must be an undiscovered organic disorder—actively impedes therapeutic insight and pathologizes the soul’s autonomous life. Hillman sharpens the polemic: analysis, he argues, courts ruin whenever it adopts medicine’s ‘coherently rational materialism’ as its weltanschauung, subordinating depth-psychological inquiry to psychiatric categories. Together these voices identify a tension between the explanatory power of the biological framework and the irreducible claims of soul, meaning, and experience. The debate is not anti-scientific; it is a contest over the limits of one particular scientific ontology. Sardello and Maté press the critique into cultural diagnosis, while Damasio and McGilchrist complicate it by showing that even neuroscience, properly understood, resists crude materialism.