Abstract
Formal epistemologists often claim that our credences should be representable by a probability function. Complete probabilistic coherence, however, is only possible for ideal agents, raising the question of how this requirement relates to our everyday judgments concerning rationality. One possible answer is that being rational is a contextual matter, that the standards for rationality change along with the situation. Just like who counts as tall changes depending on whether we are considering toddlers or basketball players, perhaps what counts as rational shifts according to whether we are considering ideal agents or creatures more like ourselves. Even though a number of formal epistemologists have endorsed this type of solution, I will argue that there is no way to spell out this contextual account that can make sense of our everyday judgments about rationality. Those who defend probabilistic coherence requirements will need an alternative account of the relationship between real and ideal rationality.
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Notes
See Plantinga (1993), p. 143.
See Foley (1993), pp. 159–160.
See Staffel (2020), p. 3. Italics in the original.
Those who forward similar criticisms include Cherniak (1986), Goldman (1986), Hacking (1967), and Kitcher (1992). Many authors motivate the Relevance Objection by arguing that, since ought implies can and we are incapable of satisfying ideal rationality requirements, then probabilistic coherence norms do not apply to us. Here, the motivation for the relevance worry comes from our ordinary judgments about rationality. If we often think credences are rational even when they aren’t representable by a probability function, then what does probabilistic coherence have to do with our rational requirements?
Advocates of this position include Christensen (2004, 2007), Smithies (2015), and Zynda (1996). Even though they all agree that credences are rational only insofar as they approximate the credences of ideal agents, there is no consensus as to what such approximation comes to—see Sect. 2 of this paper.
In this paper, we will primarily consider ‘rational’ as it is applies to credences and credal states, though we also often speak of rational beliefs, rational actions, and rational persons as well. For some thoughts about ‘rational’ as it applies to persons, see Sect. 6, and for further applications of the idea that ‘rational’ is an absolute gradable adjective, see Siscoe (2021, Forthcoming, a, b).
See Smithies (2015), p. 2780.
Because of its advantages in accounting for the relative/absolute distinction (Kennedy 2007), I have opted for the scale approach, though this choice is between competitors. Those who side with the more influential scale approach include Cresswell (1977), Heim (2000), Kennedy (2007), and von Stechow (1984), while the primary competitor, a view on which the basis for comparison are quantifications over possible precisifications of the adjective’s extension, is considered by Fine (1975), Kamp (1975), Klein (1980), Larson (1988), and Pinkal (1995).
By adopting the view on which the extension of gradable adjectives includes those items that “stand out” relative to the underlying measurement, I am forwarding a view advanced by Kennedy (2007), Kennedy and McNally (2005), and Rotstein and Winter (2004). The view that gradable adjectives enlist a standard of comparison, however, has an even more extensive lineage—see Barker (2002), Bartsch and Venneman (1972), Bierwisch (1989), Cresswell (1977), Fine (1975), Kamp (1975), Klein (1980), Lewis (1970), Pinkal (1995), Sapir (1944), von Stechow (1984), and Wheeler (1972).
See Smithies (2015), p. 2781. Earman (1991), Staffel (2020), and Zynda (1996) all point out that it is not clear how ordinary agents can be thought of as approximating ideal rationality, with Smithies (2015) and Zynda (1996) providing positive proposals for how to understand approximations of ideal rationality.
See Christensen (2004), p. 152.
See Smithies (2015), p. 2791.
See Staffel (2020), p. 23. Italics are my own.
See Unger (1975), Ch. 2.
See Lewis (1979), p. 353.
The view that ‘rational’ is an absolute gradable adjective is anticipated by Sorensen’s (1991) claim that rationality is an absolute concept.
For work distinguishing between structural and substantive rationality along these lines, see Fogal (2020), Neta (2015), Pryor (2018), Scanlon (2007), and Worsnip (2018). Thank you to an anonymous reviewer for urging me to include discussions of both structural and substantive rationality. For those that regard Normality as a constraint on structural rationality, they can skip the discussion of substantive rationality.
Complete raw survey data for all of the empirical work contained in this paper can be found in the Appendix. A similar study was used to argue that ‘rational’ is an absolute gradable adjective in Siscoe (Forthcoming, b).
One possible issue with appealing to this case is the worry that it does not stay sufficiently agnostic about what the best account of approximation might be, an issue that arose at the end of Sect. 2. Recall though that the issue of approximation comes into play when we cannot make the inferences necessary to mirror the credences of ideally rational agents. In Simple Addition, however, the failures of rationality do not result from not possessing the required reasoning powers. Instead, in Simple Addition, it is obvious that Pete and Joe could be more rational by having a credence that is closer to one, making it clear that it is more rational to have a credence of 0.7 than a credence of 0.5. Thank you to an anonymous reviewer for encouraging me to further discuss how the test cases of structural rationality interact with the issue of approximation.
It is worth noting that there is disagreement about whether imprecision is truth-conditional. Those who take all loose talk to be strictly speaking false include Kennedy and McNally (2005), Lasersohn (1999), Sperber and Wilson (1985), and Unger (1975), while those who have offered accounts on which imprecise uses can be true include Krifka (2002, 2007), Lewis (1979), Sauerland and Penka (2011), and Solt (2014). While important, the question of how imprecision interacts with truth is orthogonal to whether or not ordinary uses of ‘rational’ are in fact imprecise, so I will not address these issues here.
See Smithies (2019), p. 237.
See Turri (2010).
Smithies (2015), pp. 2782–2785, adopts just this sort of unorthodox account.
See Cohen (2016).
Another issue that arises for the propositional rationality proposal is that it potentially undermines the Contextual Rationality solution from the start. If probabilism is a theory of propositional rationality and we typically evaluate whether credences are doxastically rational, this raises questions about how the two notions interact. Are there two separate scales, one for propositional rationality and one for doxastic rationality, and if there are, doesn’t this undermine the thought that our ordinary evaluations of rationality are approximations of probabilistic coherence? Thank you to an anonymous reviewer for pointing out this difficulty with the propositional rationality proposal.
This case, along with a similar study, are also addressed in Siscoe (Forthcoming, a).
See the entry for ‘rational,’ Oxford English Dictionary, 3rd Edition (2008).
This is also known as the identity test, see Asher (2011), Bach (1998), Cruse (1982, 1986, 2011), Falkum and Vicente (2015), Gillon (2004), Lakoff (1973), Sennet (2016a, 2016b), and Zwicky and Sadock (1975). The conjunction reduction test has been employed for a wide range of philosophical applications, including debates over ambiguity theories of definite descriptions, Koralus (2013) and Sennet (2002), and know how, Stanley (2005). Unfortunately, no tests for ambiguity are infallible, but a zeugmatic judgment provides strong reason to think that a term is ambiguous. Geeraerts (1993), Moldovan (2021), and Viebahn (2018) note that the conjunction reduction test is especially vulnerable to false negatives in cases of polysemy, but we can see with (36) that ‘rational’ can be used zeugmatically.
For another author who uses the conjunction reduction test to argue for the polysemy of ‘healthy,’ see Sennet (2016b).
Another popular test for ambiguity is the contradiction test, see Cruse (1986, 2011), Sennet (2016a, 2016b), and Zwicky and Sadock (1975). However, because the two senses of ‘rational’ typically modify different types of objects, it is difficult, if not impossible, to create contradiction test cases using the capacity and sanctioning senses of ‘rational.’
In other work, I argue that other instances of the sanctioning use of ‘rational’ are also absolute gradable adjectives, including when ‘rational’ applies to actions and beliefs, see Siscoe (2021, Forthcoming, a).
For a similar proposal, see Wedgwood (2017), ch. 3.
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For helpful comments and feedback, I am grateful to Bob Beddor, Bob Bishop, Stew Cohen, Juan Comesaña, Ted Hinchman, Liz Jackson, Jack Justus, Mark Satta, Adam Sennet, Julia Staffel, Marshall Thompson, Chris Tucker, Zina Ward, Jonathan Weinberg, Guyu Zhu, and audiences at the Canadian Philosophical Association Congress, the American Catholic Philosophical Association, and the Central Division Meeting of the American Philosophical Association.
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Siscoe, R.W. Real and ideal rationality. Philos Stud 179, 879–910 (2022). https://doi.org/10.1007/s11098-021-01698-x
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DOI: https://doi.org/10.1007/s11098-021-01698-x
Keywords
- Ideal rationality
- Probabilistic coherence
- Logical omniscience
- Gradable adjectives
- Imprecision