positronic adj.

related to or designed to use positrons

The 1936 James Blish quote aside, this term is chiefly associated with Isaac Asimov, in the ‘positronic brain’ that controlled robots. The supposed technical details were vague, but it was not practical to create a positronic brain that did not incorporate the Three Laws of Robotics. In later use among other authors, still generally used in reference to computer circuitry.


  • 1936 J. Blish Trail of the Comet in Planeteer (#5) Mar. 6 page image James Blish bibliography

    ‘What’s up?’ The Planeteer brought out a heavy hammer and applied it diligently to the slats of the crate. ‘Positronic—uh—secondary screen—’ he replied, between mightly [sic] tugs.

  • 1941 I. Asimov Liar! in Astounding Science Fiction May 44/1 page image Isaac Asimov bibliography

    By exact count, there are seventy-five thousand, two hundred and thirty-four operations necessary for the manufacture of a single positronic brain.

  • 1941 I. Asimov Liar! in Astounding Science Fiction May 44/1 page image Isaac Asimov bibliography

    We've produced a positronic brain of supposedly ordinary vintage that’s got the remarkable property of being able to tune in on thought waves.

  • 1956 I. Asimov Naked Sun in Astounding Science Fiction Oct. 24/2 page image Isaac Asimov bibliography

    He knew a positronic brain…nestled in the hollow of the skull. He knew that Daneel’s ‘thoughts’ were only short-lived positronic currents.

  • 1995 P. David Captain’s Daughter i. ii. 16 Peter David

    Thousands of landing-party assignments had been fed into a vast database, processed through positronic circuitry as perfected in the M9 computer.

  • 1996 W. Shatner Return xix. 154 William Shatner

    His positronic brain had had enough processing time to review the contents of the last four standard years of the journal.

  • 1998 W. Shatner et al. Spectre xxvi. 308 bibliography

    My positronic net is capable of operating within a relativistically accelerated frame of reference for short periods of time.

  • 2005 C. Doctorow I, Robot in Year’s Best SF 11 (2006) 465 page image Cory Doctorow bibliography

    But it gave Arturo the willies. It was a machine designed to kill other machines, and that was all right with him, but it was run by a non-three-laws positronic brain. Someone in some Eurasian lab had built this brain—this machine intelligence—without the three laws’ stricture to protect and serve humans. If it had been outfitted with a gun instead of a pulse-weapon, it could have shot him.

Research requirements

antedating 1941

Earliest cite

I. Asimov 'Reason'

Research History
Mike Christie submitted a 1941 cite from Isaac Asimov's 'Reason'.
Ben Ostrowsky submitted a 1936 cite from James Blish.
Ben Ostrowsky submitted a 2005 cite from Cory Doctorow.

Earliest cite in OED2: 1948; updated to the 1941 Asimov example in OED3.

Last modified 2023-02-01 22:10:40
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.