This is a short science fiction story about a computer that is put out of action by being presented with a paradox. The computer runs a space station on a distant planet and is supposedly failsafe. A visitor makes a bet that he can bring the computer to a standstill. He does this by giving it a paradox. The computer shuts down in order to concentrate on the insoluble paradox.

1 Answer 1


"The Monkey Wrench" by Gordon Dickson, first published in Astounding Science Fiction, August 1951, available at the Internet Archive. From Wikipedia:

In this story, Lowland society lawyer Cary Harmon drops in unannounced on the weather station of meteorologist Burke McIntyre, high in the Lonesome Mountains, a jagged chain of the deserted shorelands of Venus's Northern Sea. Curious about Burke's hermit's existence, Cary queries to gain knowledge of how Burke works. The Brain, a newly installed computer, does all observations, and Burke, by himself, just sits at the desk and prepares weather data for transmission to the Weather Center down at the Capital City.

Cary tries to find fault in the machine, but Burke proudly argues that the Brain, "A big tin god", is invulnerable, that it can never break down. Along the debate, Burke claims that any bank out of the twenty could handle any situation, and if a situation too big for one to handle arose, it just hooked in with one or more of the idle banks until it was capable of dealing with the situation.

Theoretically, it's possible for the machine to bump into a problem that would require all or more than all of its banks to handle. For example, if this station suddenly popped into the air and started to fly away for no discernible reason, the bank that first felt the situation would keep reaching out for help until all the banks were engaged in considering it, until it crowded out all the other functions the machine performs. But even then, it wouldn't overload and burn out. The banks would just go on to considering the problem until they had evolved a theory that explained why we were flying through the air and what to do about returning us to our proper place and functions.

Despite that, Cary happily makes a bet that he could gimmick the machine in one minute. He successfully does so by throwing at the machine a metaphoric monkey wrench - a paradox:

You must reject the statement I am now making to you, because all the statements I make are incorrect.

With the Brain dedicating all of its banks to working on the paradox, the consequence of Cary's action finally bears down upon the pair, as the harsh negative temperatures of Venus rapidly sets in.

  • 2
    I don't know who's the bigger smuck, the guy that told it the paradox, or the programmers involved with its creation
    – user16696
    Jul 9, 2015 at 1:07
  • 3
    Why didn't the machine solve the "paradox"? Evidently, Cary makes correct statements and incorrect statements. This statement is one of the incorrect ones. Jul 9, 2015 at 1:50
  • @PaulDraper Computers aren't good at "evidently". But yeah, it really should be "You must reject the statement I am now making to you, because it is incorrect".
    – DavidS
    Jul 9, 2015 at 10:44
  • 1
    I remember reading this story in some anthology in which the editor had added a comment after the story ended. He pointed out that by the 1980s, it was quite common for people to have a computer accidentally get stuck in an endless loop -- but it was also easy to fix. If necessary, you simply rebooted the computer to start all over from scratch.
    – Lorendiac
    Oct 14, 2018 at 23:14
  • If this is the correct answer to the question, please mark it as such so the question is shown as having been answered.
    – Some Guy
    Mar 1, 2021 at 4:46

Not the answer you're looking for? Browse other questions tagged or ask your own question.