Turing's Wager

Turing's Wager is a philosophical argument that claims it is impossible to infer or deduce a detailed mathematical model of the human brain within a reasonable timescale, and thus impossible in any practical sense. The argument was first given in 1950 by the computational theorist Alan Turing in his paper Computing Machinery and Intelligence, published in Mind (Turing 1950, p. 453). The argument asserts that determining any mathematical model of a computer (its source code or any isomorphic equivalent such as a Turing machine or virtual simulation) is not possible in a reasonable timeframe.[1] As a consequence, determining a mathematical model of the human brain (which is, by its nature, more complicated) must also be impossible within that timeframe.

Effect of modern technology on wager

It has been argued that modern neuroimaging techniques will allow researchers to create accurate simulations of the human mind within the 21st century (Kurzweil 2012; Markram 2012, Fildes 2009), thereby overcoming the wager.[2] Others have argued that such claims are unjustified (Thwaites et al. 2017).

Relationship between Turing's Wager and the Turing Test

The Turing Test attempts to define when a machine might be said to possess human intelligence, while Turing's Wager is an argument aiming to demonstrate that characterising the brain mathematically will take over a thousand years. While building an artificial intelligence and mapping the human brain are both difficult endeavours, the former is actually a sub-problem of the latter (Thwaites et al. 2017).


  1. ^ Turing suggests 1000 years as a reasonable timeframe (Turing 1950, p. 453).
  2. ^ Turing's Wager should not be confused with 'A Wager on the Turing Test', a real-life wager between Kurzweil and Mitchell Kapor over whether a computer will pass the Turing Test by 2029 (Kurzweil & Kapor 2009).


  • Fildes, Jonathan (2009). "Artificial brain '10 years away'". BBC News Online. London. Retrieved 17 June 2017. Henry Markram, director of the Blue Brain Project [...] told the TED Global conference in Oxford that [...] 'It is not impossible to build a human brain and we can do it in 10 years.'
  • Kurzweil, Ray (2012). How to Create a Mind: The Secret of Human Thought Revealed. New York: Viking Books. ISBN 978-0-670-02529-9.
  • Kurzweil, Ray; Kapor, Mitchell (2009). "Chapter 27: A Wager on the Turing Test". In Epstein, Robert; Roberts, Gary; Beber, Grace (eds.). Parsing the Turing Test: Philosophical and Methodological Issues in the Quest for the Thinking Computer. Dordrecht: Springer Netherlands. pp. 463–477. doi:10.1007/978-1-4020-6710-5_27. ISBN 978-1-4020-6710-5.
  • Markram, Henry (2012). "The Human Brain Project". Scientific American. 306 (6): 50–55. Bibcode:2012SciAm.306f..50M. doi:10.1038/scientificamerican0612-50. PMID 22649994.
  • Thwaites, Andrew; Soltan, Andrew; Wieser, Eric; Nimmo-Smith, Ian (2017). "The difficult legacy of Turing's wager". Journal of Computational Neuroscience. 43 (1): 1–4. doi:10.1007/s10827-017-0651-y. PMC 5502069. PMID 28643213.
  • Turing, Alan (1950). "Computing machinery and intelligence". Mind. 59 (236): 433–460. doi:10.1093/mind/LIX.236.433.