Magical idealism also addresses the idea of health. Novalis derived his theory of health from the Scottish physician John Brown's Brunonian system of medicine, which sees illness as a mismatch between sensory stimulation and internal state. Novalis extends this idea by suggesting that illness arises from a disharmony between the self and the world of nature. This understanding of health is immanent: the "magic" is not otherworldly, it is based on the body and mind's relationship to the environment. According to Novalis, health is maintained when we use our bodies as means to sensitively perceive the world rather than to control the world: the ideal is where the individual and the world interplay harmoniously.   David Krell argues, however, that there is an anxiety in Novalis's sense of magical idealism. In Krell's view, its mutuality denies actual touch, which is seen by Novalis to inevitably lead to death. Krell suggests that magic he sees in Novalis is that of "distant touch", which Krell calls thaumaturgic idealism.