The traditional conception of the a priori


In this paper, we explore the traditional conception of a prioricity as epistemic independence of evidence from sense experience. We investigate the fortunes of the traditional conception in the light of recent challenges by Timothy Williamson. We contend that Williamson’s arguments can be resisted in various ways. En route, we argue that Williamson’s views are not as distant from tradition (in particular, from Kant) as they might seem at first glance.

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  1. 1.

    We are grateful to an anonymous referee for pointing this out.

  2. 2.

    Much of the material in this chapter of Williamson (2007b) is related to the content of Williamson (2007a), but there are some additions and other differences.

  3. 3.

    There might be various other ways in which experience can play a non-evidential but more than enabling role. We discuss some of the possibilities in Sect. 5 below.

  4. 4.

    Williamson considers it a risk that ‘far too much will count as a priori’ if we go anything like this route (see Williamson 2007a, p. 112). He mentions this risk during his discussion of the counterfactual:

    1. (25)

      If these marks had been at least nine inches apart, they would have been at least nineteen centimetres apart.

    Perhaps Williamson finds it troubling to classify (25) as a priori, but we see no particular problem with doing so (except, perhaps, for some irrelevant skirmishing about how we know of the existence of the referents of ‘these marks’). Vague worries about ‘far too much’ counting as a priori don’t yet trouble us, in the absence of any clear and convincing examples of misclassified cases. Thanks to an anonymous referee for encouraging us to engage with this reply.

  5. 5.

    Anna-Sara Malmgren (2011, pp. 308ff) raises a structurally similar concern about Williamson’s assuming elsewhere that a single capacity is responsible for all or most of our counterfactual judgments.

  6. 6.

    We don’t mean to suggest this is our preferred view, only that nothing Williamson says tells against it, or various structurally similar alternatives.

  7. 7.

    Cf. Ichikawa (2013), wherein a view is developed that can allow for empirically-informed imagination to be involved in doxastic justification for a proposition p by enabling us to capitalize on a pre-existing a priori propositional justification for p.

  8. 8.

    This point is also noted by Jonathan Jenkins Ichikawa in his blog post ‘Williamson on Apriority’, available at:

  9. 9.

    Williamson gives no reason to think that his descriptions of Norman’s processes and methods are immune to this sort of thing. It is also worth noting that in the vicinity of this point lurks the broader concern that any Williamsonian attempt to maintain that the epistemic properties of a belief are determined by the processes or methods by which that belief is formed must address a version of the generality problem that plagues process reliabilism.

  10. 10.

    See footnote 9.

  11. 11.

    Thanks to audience members at the Universities of Cologne and Calgary for raising this suggestion.

  12. 12.

    Indeed, Williamson himself discusses the possibility of experience providing evidence without consisting in it (2000, p. 197). Thanks to Jonathan Jenkins Ichikawa for pointing this out.

  13. 13.

    Here we basically follow Strawson’s (1970) characterization of Kant’s notion of imagination.

  14. 14.

    Here is how Kant introduces a prioricity and a posteriority in the opening paragraph of Critique of Pure Reason:

    [Experience] tells us, to be sure, what is, but never that it must necessarily be thus and not otherwise. For that very reason it gives us no true universality, and reason, which is so desirous of this kind of cognitions, is more stimulated than satisfied by it. Now such universal cognitions, which at the same time have the character of inner necessity, must be clear and certain for themselves, independently of experience; hence one calls them a priori cognitions: whereas that which is merely borrowed from experience is, as it is put, cognized only a posteriori, or empirically. (A1–2 / B2)

    Kant motivates the a priori/a posteriori distinction by pointing out that experience alone does not give knowledge of necessity and university. For more on Kant’s notion of a priori knowledge, see Hanna (1998).

  15. 15.

    BonJour holds that experience in the relevant sense carries only information on particular, contingent features of the world, as contrasted with other possible worlds (see p. 8). He argues that if the conclusion of an inference genuinely goes beyond the content of experience (if, e.g., it is general or necessary), then it is impossible that the inference is justified only by appeal to that same experience.

  16. 16.

    ‘... it is only by means of this transcendental function of the [productive] imagination that even the affinity of appearances, and with it the association and through the latter finally reproduction in accordance with laws, and consequently experience itself, become possible; for without them no concepts of objects at all would converge into an experience. ... in itself the synthesis of the imagination, although exercised a priori, is nevertheless always sensible, for it combines the manifold only as it appears in intuition, e.g., the shape of a triangle.’ (A123–4)

  17. 17.

    ‘Thus, if Conservatism is true, then our perceptual beliefs are well-founded only if they are based on our independent justifications to reject skeptical hypotheses about our experiences. It’s hard to see that we actually do base our perceptual beliefs on any such independent justifications, whether or not it is in principle possible for us to do so. ... A major advantage of Liberalism is that it is psychologically undemanding  ...’ (pp. 118–119)

  18. 18.

    Neta (2010) also defends such a variant of liberalism.

  19. 19.

    See also Ichikawa and Jarvis (2013, pp. 169–170). The authors are indebted to Jonathan Jenkins Ichikawa for discussions that brought the shape of this point into focus for us.

  20. 20.

    Recall the argument of Williamson (2007a, p. 112): ‘Nevertheless, their role may be more than purely enabling. Many philosophers, native speakers of English, have denied (26) ... They are not usually or plausibly accused of failing to understand the words ‘know’ and ‘believe’.

  21. 21.

    Silins borrows the term ‘entitlement’ from Wright (2004) to refer to the positive epistemic status of the epistemic backdrop. One important difference between Silins-style and Burge-style views is that the former is an internalist about entitlement, and the latter treats it in an externalist (or more narrowly reliabilist) way. But that difference does not impact the use to which we put the two views here.

  22. 22.

    See e.g. Jenkins (2008b), pp. 437–438.


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The authors would like to thank audiences at the Universities of Alberta, Calgary, Georgia and Cologne for valuable feedback on earlier versions of this material. We are particularly indebted to Uygar Abaci and Jonathan Jenkins Ichikawa for comments and discussion on late-stage drafts. Lastly, we thank the Government of Canada for supporting Masashi Kasaki’s research for this paper during a Government of Canada Post-Doctoral Research Fellowship.

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Correspondence to C. S. I. Jenkins.

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Jenkins, C.S.I., Kasaki, M. The traditional conception of the a priori. Synthese 192, 2725–2746 (2015).

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  • A priori
  • A posteriori
  • Kant
  • Williamson
  • Casullo
  • Jenkins
  • Evidence
  • Empirical