Suppose I tell you that the Sanskrit closest equivalent to "philosophy" is ānvīkṣikī. What else is needed in order for you to testimonially know that ānvīkṣikī means "philosophy"? Think for a second before checking the (standard) answers below.
- a) That you did not know it already from another source
Else, it would not be testimonial knowledge.
- b) That there are no epistemic or psychological defeaters
That is, should I tell you that most industrial dyes are produced in South Africa, you would probably be surprised (after all, this is a philosophical blog, and no one is expected to know anything about industrial processes). You might think of gooogling my name or reading my cv or my blog… nowhere you would find any connection with dyes. You would now have a serious defeater to the testimonially conceived belief that most dyes are produced in South Africa. Similarly, should you know already that most dyes are indeed produced in China, or that South Africa has a very weak industrial activity, your belief would also be defeated. Last, your belief would also be defeated if you should know me as a usual lyer (or as an unreliable speaker).
- c) That it is true that ānvīkṣikī means "philosophy"
Else, we would not be able to distinguish between Gettier cases and real knowledge.
Jennifer Lackey (in her 2008 book) adds three further conditions:
- d) That "the proffered testimony [is] reliable, truth-conducive, or otherwise epistemically acceptable" (p. 159)
If you came to rightly know that ānvīkṣikī means "philosophy" just because I accidentally typed the right sequence on my keyboard, while in fact thinking to write something else (say, anvikisi, which is no genuine Sanskrit word), then yours is no testimonial knowledge.
- e) That the listener "is a reliable or properly functioning recipient of testimony" (p. 164)
That is, if you are inclined to gullibility, then your absence of defeaters does not really count. Vice versa, if you always mistrust people, the presence of defeaters will not count.
- f) That the environment in which you receive my testimony "is suitable for the reception od reliable testimony" (p. 167)
If you are suitated in a massively unreliable epistemic environment (for instance, if you grow up as child of people who taught you that there is nothing like "Sanskrit philosophy" and that, therefore, there cannot be any such word), yours cannot be knowledge.
Lackey thus ends up refuting both reductionism (a topic I have not discussed in this post) and non-reductionism (i.e., the idea that testimony is a distinct source of knowledge, not reducible to inference or any other source). Her book is a pleasure to read and is full of well-thought counter-examples. It is nonetheless hard for me to avoid the feeling that one will end up with a "sacred epistemological garden" of true and perfect knowledge in which almost nothing is allowed, leaving our usual epistemic life out, although we acquire through testimony most of our beliefs.
What do readers think? Better to have less "knowledge", but sound?
For some thoughts of mine on the fundamental importance of testimonially acquired knowledge, see this post. If, by the way, you are curious about views on Testimony in Indian thought, check the label "Epistemology of Testimony" in my new blog or the label "śabda" in my old one).