The term ghost in the machine was first coined by a philosopher called Arthur Koestler.

Is this term common enough that almost every native English speaker has heard of it?

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    A good way to check is to compare your phrase with another common phrase in books.google.com/ngrams Commented Sep 14, 2017 at 9:05
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    Yes, that would be fine. Any common phrase, you can compare a few different ones if you like. Commented Sep 14, 2017 at 9:11
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    I think it very unlikely that "almost all native English speakers have heard of it". It is actually a book title in the field of philosophical psychology - not the sort of thing that the "man on the Clapham omnibus" discusses with his mate on his way to work - in between the racing tips, and last night's football. .
    – WS2
    Commented Sep 14, 2017 at 9:14
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    Although I suspect that a good number of people will have heard of it -- but that's as far as it goes. Most of those people, even, won't have any idea what it means or refers to.
    – Andrew Leach
    Commented Sep 14, 2017 at 9:17
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    It's an album by the 80s Brit-pop group "The Police" :)
    – Mari-Lou A
    Commented Sep 15, 2017 at 19:52

1 Answer 1


As suggested, Google Books can give some indication of how frequently an expression is used in writing. The expression comes from philosophy and its usage appears to have increased in recent decades. There is no evidence that it has become a popular expression, though its usage by computer programmers may have helped in that respect as suggested by the Grammarist.

  • Ghost in the machine is a phrase that arose in the field of philosophy, though it is slowly making its way into more mainstream English usage.

  • The ghost in the machine means the consciousness or mind carried in a physical entity. Gilbert Ryle coined the term in his 1949 work The Concept of Mind as a criticism of René Descartes. Descartes believed in dualism, the idea that the human mind is not physical, that it exists independently of the human brain. Ryle referred to this idea as the ghost in the machine. He believed that human consciousness and mind are very dependent on the human brain. The term ghost in the machine has come to also describe the supposed consciousness in a device that behaves as if it has a will that is independent of what the human operator wants the device to do. Computer programmers have appropriated the term ghost in the machine to explain when a program runs contrary to their expectations. The idiom ghost in the machine is a metaphor, which is a comparison that is made figuratively.

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    It should be noted that the computer programmers' meaning of the phrase, defined in the bolded sentence is quite different from its meaning in the philosophical contexts, that the first half of the excerpt is about. The phrase may thus be confusing if one intends it in one of these senses, and one's audience is used to the other one.
    – jsw29
    Commented Jan 6, 2020 at 17:38

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