ABSTRACT
The traditional readings of Locke's and Hume's forms of non-presumptivism would seem to be what one could characterize as pessimistic, given that they both presume that testimony, without careful monitoring of the source of the testimony on the part of the recipient, is an unreliable source of information. Hume seems to tie our reliance on testimony, in the normal case, to our general knowledge of facts about human psychology. Adopting Hume's prior plausibility strategy, in other words, leads us falsely to assess the reliability of our sources of information. Given the cognitive demands required to engage in positive argument in support of one's beliefs, one can make a parallel argument that it is unreasonable to require even of adults that they provide argumentative support for their acquisition of information on the basis of testimony. The version of this argument against non-presumptivism that people consider is one that Adler presents, in the context of his discussion in favor of optimistic non-presumptivism.
