On SciFi.SE there's a question about the origins of "captive brains" in literature. Upon seeing the question I presumed it originated as a philosophical thought experiment (and then made it's way to popular culture) but it seems the opposite may be the case - and there was a good span of time in-between.

From the accepted answer to that question, "the 1932 novelette "The Affair of the Brains" by "Anthony Gilmore" (Harry Bates and Desmond W. Hall)" is the oldest known description of brains-in-vats.

The earliest cited source in the SEP entry on the thought experiment is Putnam's 1981 Reason, Truth, and History - nearly 50 years later. The Wikipedia article on Putnam further alludes that the thought experiment is "his". However the Wikipedia article on Brain in a vat indicates Gilbert Harman's 1973 Thought originated it. The related Isolated brain article includes a history of the concept physiologically, and lists 1812 as the year the action, in rough form, was first proposed. The article also describes an isolated brain as a "inherently philosophical idea [that] has also become a staple of many science fiction stories", implying the concept was actually explored philosophically before making its way to the literature.

My questions:

  • What actually came first, the philosophy or the fantasy?
  • What exactly did Harman introduce in Thought?
  • Which other pre-Putnam works explore the Brain-in-a-vat (specifically, not just Cartesian Evil Genius experiments in general)?
  • 2
    On p.5 Harman says "You might be sound asleep and dreaming - or a playful brain surgeon might be giving you these experiences by stimulating your cortex...with wires running into your head from a large computer...Maybe you were in an accident and all that could be saved was your brain, which is kept alive in the laboratory." This is from the new printing but I assume it is unchanged.
    – Johannes
    Commented Jan 20, 2016 at 22:13
  • "Boltzmann brains" are related, and earlier.
    – Dave
    Commented Jan 20, 2016 at 22:39
  • One could also speculate that these thought experiments were partly inspired by well known experiments using electrical neural stimulation especially by Wilder Penfield. Apparently he did his work around 1930-50. Penfield reported that stimulation caused hallucinations and memory recollections in patients. It's very likely that Putnam and other philosophers knew about these experiments.
    – Johannes
    Commented Jan 21, 2016 at 1:36
  • Didn't Descartes consider that an evil demon might be messing with his perceptions?
    – user4894
    Commented Feb 24, 2016 at 1:37
  • @user4894 yes, and there are many other examples of philosophers exploring fictional perceptions (see Conifold's answer). The question is about the origins of the brain-in-a-vat specifically.
    – dimo414
    Commented Feb 25, 2016 at 2:30

2 Answers 2


Putnam certainly deserves credit for the colorful realization, but philosophically brain in a vat/isolated brain issues are traced back (including by SEP) to Cartesian evil demon , which predates not only Putnam, the Matrix and other modern implementations of non-stop hallucinations, but even 1812 and Frankenstein. Even before Descartes Avicenna's Floating Man thought experiment imagined an "isolated mind" scenario, although not for the purpose of pervasive deception of demon-fooled or envatted brains, but rather for another Cartesian purpose, disembodied minds, with a man

"created at a stroke, fully developed and perfectly formed but with his vision shrouded from perceiving all external objects - created floating in the air or in the space, not buffeted by any perceptible current of the air that supports him, his limbs separated and kept out of contact with one another, so that they do not feel each feel".

The roots of the pervasive doubt and radical skepticism, symbolized by the envatted brains, are as old as the roots of philosophy itself. If you really dig into it the grandfather of Putnam's vats and Descartes's demons is the Plato's cave, where Plato restricted mental options of his prisoners as best as he could imagine in his low-tech times, by tying their hands and immobilizing their necks so they could be deceived into taking reality to consist of dancing shadows on the wall, cast by the fire behind them. Plato himself was of course inspired by Parmenides and Zeno. In fact, Plato raises the very same issue about the shift in meaning of terms that became central to Putnam's analysis of envatted brains:"And if they could talk to one another, don’t you think they’d suppose that the names they used applied to the things they see passing before them?" Plato, like Putnam, answers "no", i.e. brains raised in a vat have different meaning of "brain" or "vat" than us, same as how Plato's prisoners have the wrong meaning of "real things", unless they listen to Plato.

After Putnam's 1981 entry Cohen and Lehrer (1983) put a new spin on the problem, sometimes distinguished as the "new evil demon" problem, which focuses not on externalism of meaning but on reliability of justification and the notion of knowledge:

"By bracketing the skeptical worries, it seems that many of your beliefs about the external world constitute knowledge. As your counterpart is systematically deceived, her beliefs about the external world do not constitute knowledge. Moreover, it seems that while you might suppose that your beliefs are produced by processes that can reliably lead you to the truth, the means by which your counterpart arrives at her beliefs are wholly unreliable... it seems the reliabilist ought to say that your counterpart’s beliefs are not justified. However, many would consider that position to be strongly counterintuitive. They are convinced that while your counterpart knows nothing, your counterpart is no less justified in her beliefs than you are in yours".

And this of course also goes back to Plato and his K=JTB (Knowledge is Justified True Belief), the "new" is the old in a new garb. This is one of those cases where one comes to appreciate Whitehead's quip:"The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato".

  • 2
    Didn't know about Avicenna's floating man. Note however that the OP asks specifically about the brain in a vat idea, not related notions like the Cartesian Demon (It is explicit towards the end of the OP). Commented Jan 21, 2016 at 23:03

Stanisław Lem, the well-known science fiction writer (who wrote Solaris, which has had two movie adaptations, and who by the way also produced a fascinating non-fiction work called Summa Technologiae, which I recommend to everyone interested in speculative philosophical explorations of technology) explored the Brain-in-a-Vat idea in a story called "Further Reminiscences Of Ijon Tichy - I", which is a part of the book called Memoirs Of A Space Traveler.

The English title was published by the MIT Press in 2020, but the original story in Polish is from 1971. In the story, Tichy meets professor Corcoran who has shelves with two rows of boxes each containing an electronic system that generates consciousness, "as does our brain", which have receptor organs that function "analogously to our sight, smell, hearing, touch, and so on."

These receptor organs are wired to a drum that is standing like an upright millstone, slowly turning, and containing special tapes, recorded electrical stimuli that correspond to the hundreds of billions of phenomena a person may encounter.

In short, the boxes are plugged into an artificial world, that makes the boxes think they are persons with experiences considered real by them.

The story ends with a discussion of the possibility in which WE are boxes on shelves and where the owner of these boxes is himself a box, etc., ad infinitum.

  • 1
    @Julius H.: Thanks very much for the edit. I re-edited "recording" back to "recorded", because that is a direct quote from this story by S. Lem.
    – plopper
    Commented Jan 14 at 21:30
  • You are welcome. Commented Jan 14 at 21:34

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