text: Speculations about the chemical structure and properties of hypothetical non-carbon-based life have been a recurring theme in science fiction. Silicon is often used as a substitute for carbon in fictional lifeforms because of its chemical similarities. In cinematic and literary science fiction, when man-made machines cross from non-living to living, this new form is often presented as an example of non-carbon-based life. Since the advent of the microprocessor in the late 1960s, such machines are often classed as "silicon-based life". Other examples of fictional "silicon-based life" can be seen in the 1967 episode "The Devil in the Dark" from Star Trek: The Original Series, in which a living rock creatures biochemistry is based on silicon. In the 1994 The X-Files' episode "Firewalker", in which a silicon-based organism is discovered in a volcano.
  In the 1984 film adaptation of Arthur C. Clarkes 1982 novel 2010: Odyssey Two', a character argues, "Whether we are based on carbon or on silicon makes no fundamental difference; we should each be treated with appropriate respect."
  In JoJolion, the eighth part of the larger JoJos Bizarre Adventure' series, a mysterious race of silicon-based lifeforms "Rock Humans" serve as the primary antagonists.