Stranger in Paradise (short story)

Plot summary

Anthony Smith and William Anti-Aut are full brothers in a "Post-Catastrophe" world where siblings sharing both parents are rare and identical twins nonexistent; they also look alike, which is embarrassing. William works in genetic engineering, called homology, studying autism, while Anthony works in telemetrics on the Mercury Project, which aims to send a robot to Mercury. The positronic brain is not yet adapted to Mercury, so an Earth computer must direct the robot, but the speed-of-light communications lag of up to twenty-two minutes makes control difficult.

Anthony recruits a homologist to design a positronic brain resembling a human brain; the leading homologist is his brother William. They work together despite mutual embarrassment. When tested in Arizona, the robot is clumsy, but William argues it was designed for Mercury. On Mercury, the robot operates smoothly.

William's solution was to use an autistic human, not a computer, to direct the robot. The brothers befriend each other after long separation.