Testimony

Epistemology has often been viewed as a debate between raitonalists and empiricists. Descartes set certainty as the gold standard of knowledge, and argued from doubt to conclusions that he considered indubitable. Empiricists insist that our senses are capable of giving us reliable knowledge of the world, and in many cases we have to rely on sense information to know things. There’s no rational argument to support to yellowness of dandelions.

What’s left out in these debates is, well, most everything, everything about the normal ways we come to know things – which involve other people. So it’s a heartening thing to see epistemology taking a turn toward a rigorous analysis of “testimony” as a source of knowledge.

Axel Gelfert’s Critical Introduction to Testimony surveys this new development in philosophy. He traces its roots to Kant’s suggestion that “one can often believe other people’s testimony more than one can believe one’s own experience” (11). Gelfert notes that “One of the guiding themes in the epistemology of testimony is that not only is it possible to partake in the knowledge of others in this way, but that it is indeed the only way we can acquire anything like the depth and breadth of knowledge we typically credit ourselves with – and which ranges from recent events in our neighborhood to distant historical occurrences in faraway countries, from social trivia reported to us by friends and colleagues to specialist findings related to us by highly trained experts.” The “cost” of this expansion is “increased epistemic dependence on others,” but that’s hardly a cost since it’s the human condition (11).

Philosophers of testimony differ, Gelfert explains, on the question of reduction. Does testimony need to be tested by some other, putatively more certain, criterion? Does an authority need to justify his reliability in each individual case of testimony (“local reductionism”)? This leads Gelfert into a discussion of Hume and Hume’s religious epistemology. Hume was not, as he is often presented, a “global reductionist.” He once wrote that “there is no species or reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men” (quoted 121). There is a sort of empirical test of testimony, but it’s not a matter of checking up on every claim but arises from “general knowledge of human nature and the social world” (122).

This of course has direct bearing on Hume’s religious epistemology and his argument against miracles. If he is not a simple global reductionist, then his claim, against miracles, that we need to test testimony by “our experience of . . . constant and regular conjunction” of states of affairs (quoted 120), is a claim about our general view of reality. The argument seems to be something like this: We should distrust testimony about miracles because in our normal experience of the world miracles don’t happen. That seems hardly to count as an argument against miracles, which by definition run contrary to normal experience. If the argument is: We should distrust testimony of miracles because we know we live in a world where miracles don’t happen, that is no longer an epistemological claim; it has become metaphysics.

In any case, Gelfert’s book provides a careful, balanced introduction to an important discussion in contemporary epistemology.