Can Reductionism fully explain the extent to which we are justified in basing our beliefs on testimony?

It is true that reductionism can explain being justified on basing our beliefs on testimony because we only tend to accept the testimony of previously trustworthy speakers; not of everyone who speaks, and through these sources of information we gain an understanding of other people's testimony we can trust leading to specific and trustworthy pool of testimonial sources.
Testimony is a reliable source of information, much like memories and observation are considered reliable sources of information, and from these sources we base many of our beliefs about the world. We form beliefs from testimony because we accept information from people whom we deem trustworthy and reliable sources information and therefore form our own beliefs about that testimony. Whether it is speculation, the experiences of others, or apparent and testable facts about the world, to accept testimony seems to be the default approach we have. (Malmgren, 2006) We base a lot of our beliefs on pure testimony, such as information about creatures under the ocean or the events of a historical war. Neither of these things are things that most of us have any experience with, so all beliefs we have about them is based on what we've been told about them, and not memories or reasoned beliefs about them. The problem with testimony, lies in its vulnerability to mis-information. It seems all too possible that if all we have to accept testimony is somebody's assertion, then we can't reliably trust that assertion as the person could be making a joke, being hypothetical or even attempting to deceive us. However, reductionism attempts to solve this issue, as we only accept the beliefs of others as true when we have a reason to believe that the speaker is reliable in asserting that testimony.
Reductionism, as an approach to testimony, puts the focus on being justified in our beliefs via the source of testimony and not on the truth of the testimony itself. Seeing as we base our acceptance of testimony on the credit of the speaker, we can assume we understand things like jokes, or hypothetical situations and, if we trust the speaker, then even if he means to deceive us, we are still justified in believing the testimony as it is still likely reliable testimony. Furthermore, people rarely have reason to lie unless they are untrustworthy people or have a reason to do so, so it seems reasonable to accept more readily that people who we deem having been previously reliable are telling the truth over telling a lie. So the focus for the reductionist approach to testimony becomes the reliability of the speaker, as it is safe to assume people are not lying, but to be justified in our beliefs about the speaker and their testimony they must have shown themselves to have been previously reliable and therefore we can assume are not attempting to deceive us or that we understand they are not joking, etc. This approach was introduced in order to tackle the issues with testimony, as if we only accept testimony from reliable sources of information, then the problem of mis-information seems to be avoided.
Coady presents a challenge to reductionism, however, in the form of a dilemma that seems to cause problems with the approach. Either, we infer reliability of testimony on common knowledge, so that the knowledge is believed because many other people collectively believe it. Though, if each of those individuals believes the information just because other people commonly believe it, it becomes a circular because each person that makes up the common group that hold the belief hold it because the rest do, so the belief would seem not to be reliable. The alternative is that each individual has observed a correlation between testimonies being given to them and experiencing that information to know that it is true; therefore giving grounds to believe future testimony due to the previous reliability. The problem here is, nobody has observed this correlation due to the nature that a large portion of testimony is unobservable, such as the deep ocean or historical events. To accept either the common knowledge idea or that we have sufficient experience idea would seem to be deeply flawed because neither of these seem to make much sense. Coady, on these grounds, suggests that reductionism must be false (Coady, 1992).
A way around this dilemma, however, is local reductionism which separates the notions of a ‘developmental’ stage and a ‘mature’ stage. (Gelfert, 2010) The idea here is that as someone grows up, accepting testimony is a vital part of development, and as a result we learn to accept certain forms of testimony mainly relying on the notion of learning and assuming we are not being lied to. By the time someone is able to be considered ‘mature’, they then must learn to distinguish if people are to be mistrusted by sub-consciously and critically assessing their reliability. (Fricker, 1995) The reliability basis is compared with your developmental sources of reliability as when you are mature you have more of an intuition not to ‘merely rely’ on the testimony given as we seem to naturally distrust strangers. This can be extended, also, with that most of our trust and knowledge comes from these few sources of testimony from developmental stages that we simply must rely on, as we get to a mature stage we learn what sort of testimony to trust from these people. For example, if you trust the testimony given by your mother at a young age and she tells you that The Guardian newspaper is a good source of information, then because you trust your mother, you will then trust the guardian. Then if the newspaper tells you that Patrick Moore was a good astronomer, you might take some of your knowledge about space from him, etc. The idea here is that when you have a need to simply trust testimony, many of the other sources of testimony you trust is often by proxy of those early developmental sources of testimony into ‘maturity’, where you then assess for yourself how trustworthy they seem.
Local reductionism seems to avoid the problem set out by Coady as it suggests that you have the experience enough from a few necessary sources of testimony to be justified in accepting other seemingly trustworthy sources. From this you can be justified in accepting testimony without needing the experience of all the information the source gives you to correlate the truth of the testimony as Coady suggests. When new sources of information at the ‘mature’ stage, have previously given testimony that stands to reason and you feel they have no reason to mis-inform you, their testimony seems reliable. The reason they seem reliable after they have given reasonable information is because they appear to know more about the subject than yourself, and you have reason to believe that they tell you information that they believe themselves. If an authority believes information to be correct and you see that authority as a reliable source, then there is sufficient justification to accept that testimony under reductionism. This does not concern common knowledge as it assumes specific specialists and authorities of a subject. This version of reductionism also avoids the problems brought about by Coady because rather than comparing testimony with the way the world is; requiring you to experience things, it is building upon your beliefs about the world based on other beliefs you already have about the world. For example, to trust a David Attenborough show in talking about the deep sea can be justified by either having other, more fundamental sources of testimony, such as your parents, tell you he is a trustworthy source. Or after watching another show of his that tells you about an animal you had experience of, you understood him as a reliable source of information and deemed him to have no reason to lie on an informative television show. As a result of either of these, you could justifiably accept David Attenborough as a reliable source of information about the deep ocean without having to experience the deep ocean for yourself.
       Reductionism does stand against the problems raised against it, as it does not seem justified in simply believing testimony unless you have a reasonable and reliable speaker giving the testimony. Considering the main argument is to give justification for the belief in testimony, then it is possible to be justified in believing testimony that isn’t true, whether it is reductionism or not. With this in mind, you must need a strong source for the testimony in order to trust the testimony, as opposed to simply accepting testimony in the same way that we simply accept reason or memories. Reductionism gives this justification and given local reductionism avoids the main problems presented against the idea of general reductionism, then it does seem to be able to fully explain the extent to which we are justified in believing testimony.

Refrences:
· Adler, J. (2006). ‘Epistemological Problems of Testimony’, Stanford Encyclopaedia of Philosophy, (ed.)
· Coady, C. A. J., 1992, Testimony: A Philosophical Study, Oxford: Oxford University Press.
· Fricker, E. (1995). Telling and trusting: Reductionism and anti-reductionism in the epistemology of testimony. Mind, 104, 393-411.
· Gelfert, A, (2010). Reconsidering the role of inference to the best explanation in the epistemology of testimony. Studies in History and Philosophy of Science. Volume 41, Issue 4,  pp.5-11
· Malmgren, A.-S. (2006). Is there a priori knowledge by testimony? Philosophical Review, 115, 199-241.