The defining characteristics anticipated for any prospective psychophysically neutral language are explored in this essay through the analysis and comparison of two previous approaches. The idea of a psychophysically neutral language was first articulated byWolfgang Pauli in the context of the dual-aspect theory of mind and matter that he developed with C.G. Jung. The first approach discussed is George Spencer Brown's Laws of Form. An overview is given, followed by a review of the critical responses and extensions of the work, (...) particularly Francisco Varela's attempt to use it to formalize biological autopoiesis and Louis Kaufman's development of Brownian algebra. The mathematical basis of Spencer Brown's calculus and its philosophical assumptions and implications are then investigated. The second approach discussed is Marie-Louise von Franz's Number and Time, an investigation of number archetypes through which she continued the inquiry begun by Jung and Pauli. The central tenets of her work are summarized and critically evaluated, and a comparison with Spencer Brown's work is carried out. Finally, implications are drawn for any future attempt to formulate a psychophysically neutral language. (shrink)