I just remembered a story—perhaps by Isaac Asimov, but the whimsy I'm remembering seems to be a bit different from his—in which a narrator describes how they have created a machine that, when told of a choice that has to be made and of the desired decision, automatically produces a superficially compelling a posteriori justification for why the desired decision is the right one. I don't remember any of the interior of the story, but the punchline is that the character deduces from the state of the world that their machine has been misappropriated by politicians, who are now using it to justify their policies.

I probably read the story in the late '80s or early '90s, but it would have been in a compilation of sci-fi stories, very likely including Asimov since that was most of what I read at the time, so that only places an upper bound on its provenance. It was in English, and probably not longer than about 5 pages.


1 Answer 1


This sounds like Reason from Douglas Adams's "Dirk Gently's Holistic Detective Agency" series as per Book referring to software where you provide facts and the conclusion you want to reach

Gordon’s great insight was to design a program which allowed you to specify in advance what decision you wished it to reach, and only then to give it all the facts. The program’s task, which it was able to accomplish with consummate ease, was simply to construct a plausible series of logical-sounding steps to connect the premises with the conclusion.

‘And I have to say that it worked brilliantly. Gordon was able to buy himself a Porsche almost immediately despite being completely broke and a hopeless driver. Even his bank manager was unable to find fault with his reasoning. Even when Gordon wrote it off three weeks later.’

‘Heavens. And did the program sell very well?’

‘No. We never sold a single copy.’

‘You astonish me. It sounds like a real winner to me.’

‘It was,’ said Richard hesitantly. ‘The entire project was bought up, lock, stock and barrel, by the Pentagon. The deal put WayForward on a very sound financial foundation.

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    I have a sneaking suspicion you wanted the answer to be Dirk Gently's Holistic Detective Agency and you asked Gordon for a justification.
    – SQB
    Dec 16, 2022 at 22:18
  • That's the one! I probably read it first at the same time as I was reading Asimov, but then I was re-reading DGHDA and LDTTS recently, and that bit must have got lodged in my memory just enough for me faintly to recall it. Thanks!
    – LSpice
    Dec 16, 2022 at 22:21
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    @LSpice: Glad i could help! I've marked the question as a duplicate, but of course, note that this is not that this is a bad question, or that this is some sort of a censure. We just like to link extremely similar questions together in the system. You will still get upvote points for your question
    – FuzzyBoots
    Dec 17, 2022 at 5:07
  • Fair enough. Thank you for explaining the system!
    – LSpice
    Dec 17, 2022 at 11:38

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