The Critique from Experimental Philosophy: Can Philosophical Intuitions Be Externally Corroborated? Max Seeger The movement of experimental philosophy criticizes traditional philosophy's armchair reliance on intuition. The critique is rarely spelled out precisely; rather, experimental philosophers simply point to the admittedly surprising results of intuition surveys, which are, roughly, that intuitions vary with factors presumed to be irrelevant to the subject matter in question.1 However, the question what is wrong exactly with armchair philosophy is rarely answered adequately.2 Jonathan Weinberg (2007) has offered what I take to be the most compelling answer so far: Reliance on philosophical intuition is problematic because we have no tools for detecting and correcting its errors. Weinberg introduces the technical term 'hopefulness' for the property of methods to allow for the detection and correction of error. A method is hopeful if it meets all or most of the following desiderata to some sufficient degree: external corroboration, internal coherence, detectability of margins, and theoretical illumination. A method is clearly hopeless when it fails to meet any of the desiderata. According to Weinberg this is the case for the philosophers' practice of appealing to intuitions. He further argues for the epistemic principle that "[a]ny putative source of evidence that is hopeless ought not be trusted" (2007, 327; emphasis omitted) and thus concludes, that the practice of appealing to intuitions ought to be abandoned (or revised). 1 For example, according to Weinberg et al. (2001) East Asians are less likely than 'Westerners' to share the Gettier intuition (i.e. the intuition that the subject in a Gettier case does not know the proposition in question). For an overview see Alexander & Weinberg (2007) and Knobe & Nichols (2008). 2 Joachim Horvath calls this the 'grounding objection' to experimental philosophy (cf. 2010, 457ff.). 2 Weinberg acknowledges that his critique of philosophical intuitions has to meet two constraints. First, it must not be self-undermining, i.e. his argument must not itself rely on hopeless intuitions. Second, the criterion of hopefulness must not be too strong, so as to classify a large set of our basic and scientific sources of evidence as untrustworthy and thus issue into general skepticism. Note that not all intuitions or even all intuitions used in philosophy are meant to fall within the scope of the critique. For example, logical and mathematical intuitions are intended to remain unscathed, as well as "the ordinary application of concepts to particulars" (Weinberg 2007, 320) and of course the epistemic intuitions which are needed to justify the principle of hopefulness. Roughly speaking, Weinberg's concern is with philosophical intuitions regarding "esoteric, unusual, far-fetched, or generally outlandish" cases (Weinberg 2007, 321).3 In this paper I restrict my discussion to what I take to be the most interesting criterion of hopefulness, external corroboration.4 A source fulfils the criterion of external corroboration iff its deliverances can be compared to and are corroborated by the deliverances of other sources. For example, my visual perception that there is a glass of wine before me can be directly confirmed by tactile, olfactory and acoustic perceptions, as well as by my background knowledge of the situation I am in. Weinberg's concern with philosophical intuition is not so much that other methods have disconfirmed its results, but rather that "there simply may be no area outside of philosophy that really can speak to" philosophical intuitions (2007, 339). The idea is that philosophical intuition is an exclusive source, i.e. the only available 3 Whether this is a viable restriction of scope is discussed by Ichikawa (forthcoming, § 3) and Horvath (2010, 461-3). The far-fetchedness-critique to thought experiments is also discussed by Sorensen (1992, 277-80) and Brendel (2004, 103-6). 4 For discussion of the other criteria see Grundmann (2010) and Ichikawa (forthcoming). 3 source of evidence for philosophical claims. The deliverances of an exclusive source, so the argument, cannot be compared to the deliverances of other sources, thus they cannot be externally corroborated. However, the argument rests on an equivocation. Weinberg's notion of external corroboration is ambiguous between a narrow and a broad reading. On the narrow reading, external corroboration is understood solely as the direct corroboration of results, i.e. corroboration by evidence from other sources showing directly that a certain result is correct (e.g. my tactile perception of the glass directly corroborates my visual perception of the glass). On the broad reading, external corroboration is understood to encompass not just direct but also indirect forms of corroboration such as successful application of a method's results in other fields. The disambiguation faces the following dilemma: On the narrow reading, Weinberg's critique will equally apply to other types of intuition (breaching the self-undermining constraint) and it will lead to general philosophical skepticism (breaching the skepticism constraint). On the broad reading, Weinberg simply has not shown that philosophical intuition (PI) does not enjoy external corroboration.5 Let me elaborate. The first horn of the dilemma is based on the narrow reading (only direct corroboration). Attributing the narrow reading to Weinberg is made plausible both by the examples he provides and by his argument for the claim that PI lacks external corroboration. He argues from PI's being an exclusive source to its lack of external corroboration, which implies the narrow reading. However, the narrow reading allows for two objections.6 5 I am here putting the discussion in terms of philosophical intuition (PI) as a source. Nothing hinges on that. The same points can be made by speaking of the method of appealing to intuitions (as Weinberg does), or by speaking of philosophical intuitions as deliverances of this method or source. 6 Elsewhere (2010) I have raised a third objection, viz. that the demand for direct external corroboration is misplaced on PI. Somewhat similarly, Ernest Sosa argues that even without 4 First, the narrow reading allows for a reductio showing that Weinberg's argument issues into philosophical skepticism. According to Weinberg, PI cannot be externally corroborated because it is an exclusive source with respect to the domains about which it speaks. However, if PI is the only available source of evidence with respect to the domains to which it speaks, and PI is not trustworthy, then there is no trustworthy source with respect to the domains about which PI speaks. Assuming that PI speaks pretty much to all philosophical domains (Weinberg's critique is not directed at just one particular domain), Weinberg's critique issues into a general skepticism regarding philosophical questions: There is no trustworthy source of evidence for philosophical claims. This is not the intended conclusion of Weinberg's critique. To be fair, there is a way out for Weinberg. He can modify the argument from saying that in principle there is no other source to the domains that PI speaks to, to saying that so far we have not found or used any source external to PI to corroborate its results. The reductio is thus defused-but it is defused by weakening the attack: Weinberg can no longer claim that in principle there is no other source that can corroborate philosophical intuitions. He can only maintain that, so far, we have either not found or not used other sources to corroborate philosophical intuitions. The second problem with the narrow reading is that it renders the mathematical and logical intuitions equally uncorroborated. What source, other than intuition, could speak to propositions such as 'p → ⌐ ⌐ p'? Doubting logical intuitions will lead to general skepticism and will render Weinberg's critique selfundermining.7 direct external corroboration we need to trust PI for lack of alternatives – we have no other choice (cf. 2011, 464). 7 See also Kipper (2010) who argues that Weinberg's critique of PI may equally undermine the grammarians' appeals to intuitions, which is an unacceptable consequence. 5 The second horn of the dilemma is based on the broad reading of 'external corroboration' which admits both direct and indirect types of corroboration. The only example of indirect external corroboration given by Weinberg is this. [L]ogic and mathematics are excellent examples of domains with hopeful intuitions. [...] [W]e have the kind of checking that comes from the successful integration of mathematics and logic into other ongoing scientific concerns; indeed, into almost all ongoing scientific concerns. (2007, 339) I take it to be uncontentious that mathematics and logics do enjoy this indirect type of corroboration. The problem with the broad reading of 'corroboration' is that Weinberg has not even tried to show that PI does not enjoy this kind of indirect corroboration. Are philosophical intuitions successfully applied in fields outside of philosophy? Most obviously, moral intuitions (as delivered by PI) successfully guide our moral and legal practices. But not only moral intuitions are relevant in our moral and legal practices. All sorts of judgments regarding justification, causation, personal identity etc. can be relevant in ascriptions of praise and blame. Secondly, philosophical intuitions, or conceptual distinctions based on them, are frequently and successfully used in the sciences. To name but one example: Elliot Sober's distinction between 'selection for' and 'selection of' (1984, 97ff.) helped generate a better understanding of natural selection and has explanatory relevance for many initially puzzling phenomena (e.g. those generated by pleiotropy or gene linkage). This distinction is based on the intuitive evaluation of a thought experiment, so, in any relevant sense, it is a result of PI. Weinberg claims that intuitions are not trustworthy since-among other shortcomings-they cannot be externally corroborated. I argued that Weinberg's notion of external corroboration is ambiguous. On a narrow reading (only direct corroboration), the demand for external corroboration is too strong, as it cannot be met by other sources such as mathematical and logical intuitions. On a broad 6 reading (direct and indirect corroboration), the demand for external corroboration can be met by philosophical intuition. References Alexander, Joshua & Weinberg, Jonathan M. 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Oxford: Oxford University Press. Sosa, Ernest (2011): "Can There Be a Discipline of Philosophy? And Can It Be Founded on Intuitions?" Mind & Language 26, 453–467. Weinberg, Jonathan M., Nichols, Shaun & Stich, Stephen (2001): "Normativity and Epistemic Intuitions." Philosophical Topics 29, 429–460. Weinberg, Jonathan M. (2007): "How to Challenge Intuitions Empirically Without Risking Skepticism." Midwest Studies in Philosophy 31, 318–343.