The media of communication occupy a middle ground between material and immaterial reality. Printed pages, celluloid strips, electromagnetic signals, and bit streams are all material phenomena. At the same time, different material media provide access to a wide variety of actual, possible, and barely imaginable worlds. Being programmable in distinctive ways, digital media have invited more or less radical claims that the boundaries between material and immaterial reality may be shifting in fundamental ways. Research addressing such boundaries ranges from the largely failed attempts since the 1950s to program a general sort of artificial intelligence (for overview, see Boden, 1996; Partridge, 1991), via an early mainstream of new-media studies embracing cyberspaces, cybercultures, and cybersocieties (Bell and Kennedy, 2000; Benedikt, 1991; Jones, 1998), to cultural criticism projecting a cyborg future and a posthuman era of life (Haraway, 1991; Hayles, 1999). Digital computers might even be thought to dissolve the distinction that René Descartes had referred to, at the outset of modern philosophy, between res extensa (extended matter) and res cogitans (thinking matter).1 In certain respects, media extend thinking matter.