A person knows that p, I suggest, only if the actual state of affairs in which p is true is distinguishable or discriminable by him from a relevant possible state of affairs in which p is false. If there is a relevant possible state of affairs in which p is false and which is indistinguishable by him from the actual state of affairs, then he fails to know that p. (Ibid, 774)Notice that the above discrimination requirement avoids the unfavourable consequences of the Gettier case described in my previous post in at least two ways. First, it omits all talk of justification and so (in at least one sense) traditional Gettier problems never arise. Second, since according to the aforementioned Gettier case S is unable to discriminate between the actual red cube and the hologram, her true belief does not constitute knowledge (thereby preserving our common-sense intuitions regarding such cases). But, and this is crucial to the point I’m getting at, what is doing the actual work in [Goldman 1976]’s reply to Gettier is the discrimination requirement, and not the notion of reliability a la (J-Rel). Admittedly, in [Goldman 1976], Goldman defines reliability in terms of a subject being able to discriminate between relevant alternatives and thus the former is taken to entail the latter. However, in later formulations of the reliability requirement, explicit appeals to discriminative abilities are increasingly omitted, and Goldman eventually comes to define a reliable process as more or less one that tends to produce true beliefs. Moreover, I do not believe this shift in Goldman’s definition of reliability is by accident. Presumably, talk of discriminative abilities falls out of Goldman’s analysis (now taken to be unnecessary) once he shifts to an explicit J-externalism, where what makes a belief justified need not be internally available to the subject.
The objection may be raised that even with the J-externalist turn in Goldman’s thinking, the discrimination requirement remains an implicit part of his account. I will not deny that this may be the case. Even so, it has long been recognised that the discrimination requirement can stand on its own, independent of any appeals to reliability (see for example [McGinn 1984]). Thus, if my claim that what is doing the work vis-a-vis Gettier is actually the discrimination requirement, rather than reliability qua reliability, then this is at least sufficient to establish that when it comes to the aforementioned Gettier case, reliability a la (J-Rel) is at best explanatorily redundant and at worst explanatorily inert. (The second more unpropitious option holds if you consider my arguments in (Part 1) persuasive.) Moreover, even if one were to reject the account of the evolution of Goldman’s thought outlined above, my more general conclusions still stand: (1) that though reliability and discrimination are classically taken to go together this need not be the case and (2) if (DR) is doing the heavy lifting in classic reliabilist replies to Gettier then the widely held assumption that (J-Rel) constitutes a successful reply to Gettier may be unwarranted.
Goldman, A. (1967), 'A Causal Theory of Knowing', Journal of Philosophy 64: 355-372.
Goldman, A. (1976), 'Discrimination and Perceptual Knowledge', Journal of Philosophy 73: 771-791.
Goldman, A. (1979), 'What is Justified Belief?' Justification and Knowledge, Dordrecht: Reidel.