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Reasoning as a source of justification


In this essay we argue that reasoning can sometimes generate epistemic justification, rather than merely transmitting justification that the subject already possesses to new beliefs. We also suggest a way to account for it in terms of the relationship between epistemic normative requirements, justification and cognitive capacities.

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  1. 1.

    Here “state” should be construed very broadly to include occurrent experiences, extended processes that the subject undergoes, and perhaps much else. Note that we make no assumption here that the state in virtue of which the subject has justification must be a purely internal state, or a state to which the subject has conscious access. Thus we are not presupposing a picture of justification that is internalist in either of these senses.

  2. 2.

    Our use of terminology here basically follows Pryor (2005a).

  3. 3.

    Broome (2001). Note that Broome clearly does not intend this to be a sufficient condition for reasoning.

  4. 4.

    We do not build it into the notion of reasoning that it is always fully conscious, or always involves a deliberate sequence of transitions among mental states. Reasoning can be automatic and largely non-conscious. But for those who prefer a more restricted notion of reasoning, the cases to be discussed below can be construed as fully conscious and deliberate.

  5. 5.

    According to Boghossian (2003, pp. 235–236) content gaps are symptomatic of cases of inferential justification. When the gap between the content of the premise state and the content of the conclusion state is too large, we have to regard the conclusion state as inferentially justified. Correlatively, most would not count the belief that there is a red circle as inferentially justified in this case.

  6. 6.

    The analogy may suggest that it is constitutive of epistemically evaluable reasoning that it is something the subject engages in intentionally. However, this is not something we assume.

  7. 7.

    See, of course, Carroll (1895).

  8. 8.

    Boghossian (2003) forcefully presses this sort of worry.

  9. 9.

    There is some ground for insisting that the transition is blind. After all, it is intuitively closely connected to one’s grasp of the material conditional that one is prepared to judge If P then Q when one judges Q by reasoning from the hypothetical assumption of P.

  10. 10.

    Searle (1980).

  11. 11.

    If necessary, of course, we can re-describe the case as one that involves a less controversial thought experiment, such as a Gettier-style scenario.

  12. 12.

    Scooter’s representation need not be visual, nor need the propositions that characterize the scenario be represented in any other specific way.

  13. 13.

    Making a judgment under a hypothetical assumption is not, of course, a matter of forming a belief but of adding a new proposition to what is being supposed.

  14. 14.

    The paradox of analysis, and the role of thought experiments in providing justification, are discussed in Balcerak Jackson (2012).

  15. 15.

    For an explicit commitment to the view that responses to thought experiments are immediately justifying seemings see Chudnoff (2011), or Bengson (manuscript).

  16. 16.

    See, for example, Pryor (2005b) and Huemer (2007).

  17. 17.

    For a much more thorough discussion of intuitions as inferential responses to hypothetical scenarios see Balcerak Jackson (manuscript).

  18. 18.

    See Williamson (2007, Chap. 5).

  19. 19.

    Let us put aside the question of whether Gonzo imagines this from a first-person perspective of somebody sitting in the cannon waiting to be shot out, or from a third-person perspective looking at himself in the cannon. Nothing here hangs on these two ways to set up the visual mental model.

  20. 20.

    It will plausibly share core aspects of the content and phenomenal character with the corresponding perceptual state. But when one engages in voluntary imaginative projects like the one described, one is rarely in danger of confusing imagination with perception. So there must also be representational and/or phenomenal differences that allow one to distinguish the visualization and the corresponding perception.

  21. 21.

    See Williamson (2007, Chap. 5).

  22. 22.

    Williamson (2007, Chap. 5) notes that the “folk theories” that allegedly underwrite these sorts of mental simulation very often include principles that are literally false. If so then the beliefs grounded by mental simulation, on the present suggestion, would not qualify as knowledge, even when they are true and justified. This is a further unwelcome result.

  23. 23.

    There is an analogy here with the observation, in the philosophy of science, that even very well-developed, successful scientific theories do not eliminate the use of scientific models in order to answer complex questions and make reliable predictions. One can find out where to erect barriers in the San Francisco Bay with minimal risk for the environment by building a model of the bay and putting it to work, even if one is not in a position to find the solution on the basis of physical and technical background knowledge. See Godfrey-Smith (2006, 2009), and for the example Weisberg (2012).

  24. 24.

    Thanks to Miriam Schoenfield for discussion here.

  25. 25.

    Broome (1999).

  26. 26.

    This is essentially Broome’s standard; cf. Broome (1999, p. 406).

  27. 27.

    There is a sense, of course, in which one is always permitted to suppose whatever one likes. Epistemically speaking, there is never anything that speaks against supposing p, because doing so incurs no commitment about how things are. But permission in this sense attaches to single suppositions. The notion of permission we are interested in, like Broome’s notion of requirement, is essentially a relational one.


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In preparing this paper we benefitted enormously from discussions with others. In particular, we are grateful for feedback from participants at the Knowledge in a World of Symbols workshop at the University of Hamburg, from participants at the Bellingham Summer Philosophy Conference, and from members of the weekly reading group of our project Understanding and the A Priori at the University of Cologne. Thanks especially to Sven Bernecker, Lars Dänzer, Blake Roeber and Miriam Schoenfield for their thoughtful comments. The research for this paper was supported by a grant from the German Research Council (Deutsche Forschungsgemeinschaft).

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Correspondence to Magdalena Balcerak Jackson.

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Balcerak Jackson, M., Balcerak Jackson, B. Reasoning as a source of justification. Philos Stud 164, 113–126 (2013).

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  • Reasoning
  • Inference
  • Justification
  • Normative requirements
  • Cognitive capacities