Abstract: This chapter focuses on the topic of testimonial justification or warrant, where the two central views on this topic are critiqued: reductionism and non-reductionism. Against reductionism, it is argued that while non-testimonial positive reasons are necessary for testimonial justification or warrant, this does not entail that the epistemic status of testimonial beliefs is reducible to the epistemic status of beliefs from other sources. Against non-reductionism, it is shown that accepting the testimony of speakers about whom hearers know nothing at all is epistemically irrational in ways that even non-reductionists are committed to finding objectionable. This reveals that at least minimal positive reasons are necessary for testimonial justification or warrant. It is concluded that testimony is neither just as basic as, nor ultimately reducible to other sources of belief and knowledge, such as sense perception, memory, and reason. Thus, both non-reductionism and reductionism in the epistemology of testimony are false.

Keywords: justification, memory, perception, reason, source of knowledge, testimony, warrant,