Reasons, Causes, and the Extended Mind Hypothesis


In this paper we develop a novel argument against the extended mind hypothesis. Our argument constitutes an advance in the debate, insofar as we employ only premises that are acceptable to a coarse-grained functionalist, and we do not rely on functional disanalogies between putative examples of extended minds and ordinary human beings that are just a matter of fine detail or degree. Thus, we beg no questions against proponents of the extended mind hypothesis. Rather, our argument consists in making use of the following necessary condition on holding a belief for a reason: To believe something for a reason, one must come to believe it in virtue of attitudes that epistemically rationalize the belief that is formed, and one must come to believe in virtue of the fact that these attitudes epistemically rationalize the new belief. We show that many external objects that defenders of the extended mind hypothesis have claimed are (in conjunction with an internal cognitive system) beliefs cannot (even partly) constitute a belief had for a reason, as they necessarily fail to satisfy the necessary condition. Our first thesis, then, is that beliefs had for reasons cannot be extended in the most interesting way specified by the extended mind hypothesis. Furthermore, if we add to our argument the premise that every token belief is something that could have been had for a reason, we can derive the stronger thesis that no beliefs can be extended in this way.

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  1. 1.

    See, inter alia, Rupert (2004, 2009), Adams and Aizawa (2008), Weiskopf (2008) and Spaulding (2012).

  2. 2.

    See Coleman (2011) for another discussion of the idea that arguments made by different parties in the debate have involved begging the question against the other side.

  3. 3.

    This necessary condition was developed by Arpaly (2006) and Wedgwood (2006), independently of one another. For a slightly different version of the necessary condition see Turri (2011).

  4. 4.

    Our argument is not directed against proponents of EMH who focus on socially distributed cognition, rather than external objects and artifacts. For further discussion see Sutton et al. (2010).

  5. 5.

    Clark and Chalmers (1998, 12). For more recent book-length articulations of EMH, see Clark (2008), Menary (2007) and Rowlands (2010).

  6. 6.

    According to some self-described ‘embodied cognition’ theories the mind is not restricted to the central nervous system, but does stop at least at the skin of the body. This intermediate position is one we will neglect in this paper, since it will not be relevant to our arguments. Thus, using the helpful taxonomy of Sutton et al. (2010: 531), we are addressing extended cognition, rather than embedded cognition or distributed cognition.

  7. 7.

    The obvious antecedents of our thought experiment are found in Dennett (1978) and Nagel (1971).

  8. 8.

    Clark and Chalmers (1998, 12–13).

  9. 9.

    See Dretske (1988, chapter 3) for one particularly clear presentation of this distinction.

  10. 10.

    Adams and Aizawa (2010, 70).

  11. 11.

    Adams and Aizawa (2010: 70).

  12. 12.

    Clark (2008, 90).

  13. 13.

    Adams and Aizawa (2008: 63–68). Rupert (2004) brings up a similar point.

  14. 14.

    Weiskopf (2008).

  15. 15.

    Rupert (2009, 38).

  16. 16.

    Rupert (2009, 38, 42).

  17. 17.

    This way of thinking about the dialectic between critics and defenders of EMH is taken from Spaulding (2012), and is perhaps a bit idiosyncratic, especially when it comes to describing the role played by the Parity Principle. However, nothing in our argument hinges upon this way of thinking about the dialectic.

  18. 18.

    Clark (2010, 44).

  19. 19.

    This criticism is not original to us. Amongst others, Spaulding (2012) makes a similar point.

  20. 20.

    Fred Dretske is perhaps the functionalist (the teleofunctionalist) philosopher of mind who has given the most attention to thinking and acting for reasons. See Dretske (1981) and especially Dretske (1988). Brandom (1994) takes a very different approach that also addresses the question of reasons in the philosophy of mind, and of course Davidson (1980) has a well-known approach to giving reasons a place in the philosophy of mind. Recently, Schroeder (2010) has argued that reductive, naturalistic philosophers of mind need to give more attention than they have to acting for reasons.

  21. 21.

    Arpaly (2006), Arpaly and Schroeder (2012), Arpaly and Schroeder (2013), Turri (2011), Wedgwood (2006).

  22. 22.

    Additional clarification of the Arpaly and Wedgwood thesis can be provided in response to the following worry raised by an anonymous referee: Consider Glenda’s belief that 789 times 987 equals 778,743. This belief results from following an algorithm that she was taught in school years ago. Say that she has no idea why this algorithm is a correct one, and say that her belief stands in no epistemically justifying logical or probabilistic relations to the rest of her belief system. Is this a case of a belief that is held for an epistemic reason yet does not satisfy the proposed necessary condition on believing for a reason?

    The answer to this question depends on why she uses the multiplication algorithm. Now, on the Arpaly and Wedgwood thesis she needn’t understand why the algorithm is correct in order for her belief to be rationalized. On the other hand, not just any causal process that results in her using the algorithm will likewise result in the belief being rationalized. Cases in which she might use the algorithm, and yet the resulting belief is not held for an epistemic reason, could include using the algorithm as a result of banging her head on the wall, or shuffling a deck of cards with a different multiplication algorithm written on each card, and then randomly drawing one card and using the multiplication algorithm written on that card to arrive at the belief. The more typical causal process, we take it, is one where she has a reason to believe that the multiplication algorithm that she learned in school is the correct algorithm to use, and that is why she uses the algorithm to arrive at the belief. In which case, this does satisfy the proposed necessary condition for holding a belief. Furthermore, in contrast to extended beliefs, Glenda’s belief can be sensitive to her epistemic reasons—for example, she may come to have an epistemic reason to believe that the multiplication algorithm that she learned in school is not the correct algorithm to use. For further discussion of this issue see below, Sect. 6.

  23. 23.

    This reading of Davidson’s case is meant to be merely illustrative. If the reader has another interpretation of it, but is happy with the epistemic cases that follow, then our main line of argument is not affected.

  24. 24.

    Again, our argument is not directed towards proponents of EMH who wish to extend the mind to include socially distributed cognition.

  25. 25.

    This is orthogonal to debates between internalists and externalists concerning epistemic justification. Externalists about epistemic justification claim that a token belief can be had for no reason, but this isn’t the same as claiming that a token belief couldn’t be had for a reason.

  26. 26.

    Indeed it has been worried, most famously by Kim (1998, 2005).

  27. 27.

    Suggested by David Chalmers. This case bears a close resemblance to the case of Wanda, who “has a portable electronic memory device that is directly jacked into her brain”, discussed in Weiskopf (2008: 271).

  28. 28.

    Now, as an anonymous referee points out, it is true that Otto could be in an epistemic position such that he could think to himself “if my notebook says X, then it is rational for me to believe X”. Does this show that the notebook inscriptions can be sensitive to Otto’s rationalizing reasons? We think that the answer is ‘no’, for notice the following difference between beliefs that result from (typical biological) memories, and Otto’s notebook inscriptions: Say Franklin has a belief that he walked his dog yesterday, and this belief results from a memory he has of walking his dog. This belief is sensitive to his rationalizing reasons, insofar as if he subsequently has reason to believe that the “memory” was really a dream, or hallucination, this rationalizing reason can result in his no longer having the belief that he walked his dog yesterday. In contrast, notebook inscriptions are causally isolated from rationalizing reasons. Say Otto’s notebook contains the words “I walked my dog on June 30”. This inscription is not sensitive to Otto’s rationalizing reasons, for if Otto subsequently has reason to believe, say, that someone else wrote those words in his notebook, this may cause him to no longer have the belief that he walked his dog yesterday, but it will have no effect on the notebook inscriptions themselves—unless, of course, a reason for action (such as a desire to remember and keep track of walking his dog) intervenes.


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We are grateful to David Chalmers, Katalin Farkas, two anonymous referees, and especially Declan Smithies for helpful comments on earlier versions of this paper.

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Correspondence to Daniel Pearlberg.

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Pearlberg, D., Schroeder, T. Reasons, Causes, and the Extended Mind Hypothesis. Erkenn 81, 41–57 (2016).

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  • Mental Causation
  • Epistemic Reason
  • Extended Mind
  • Mountain Climber
  • Token Belief