On the University of Chicago’s Theories of Media online glossary Sarah Coffey offers an interesting genealogical mapping of the concept of prosthesis. The glossary and Coffey’s essay itself performs the concept itself.
Combining the Latin pro (forward) with thesis (stressed syllable), prosthetics denotes addition or extension. The OED defines “prosthetics” in its plural form as “the branch of surgery concerned with the replacement of defective or absent parts of the body by artificial substitutes.” “Prosthetic” derives from the word “prosthesis,” which can refer to the addition of a syllable or letter at the beginning of a word, or to surgical prosthesis. The shift from the literal connotation of grammatical prosthesis to the figurative connotation of surgical prosthetics took place in the 16th century, when “prosthesis” was adopted by medical terminology to denote the substitution of an artificial body part for missing limbs or teeth (Jain 32). This article will examine prosthetics in reference to both the actual extension of the body by artificial means, and the virtual extension of the body by various forms of media.
Media theory examines the double meaning of prosthetics, as simultaneously supplementing a deficiency and signaling deficiency in the object to which it is supplied. In Marshall McLuhan‘s seminal text, Understanding Media: The Extensions of Man, he uses the concept of prosthesis to explain media’s function as “any extension of ourselves” (7). Stressing the physicality of media extensions, McLuhan describes the wheel as an extension of the foot, clothing as an extension of the skin, and electric technology as an extension of the central nervous system. Yet as media extends, it also amputates. Although electric technology extends the central nervous system, “such amplification is bearable by the nervous system only through numbness or blocking of perception” (McLuhan 43). Thus McLuhan asserts that a process he terms “autoamputation” accompanies any extension of media.