Corroboration
What others tell us is sometimes important as corroboration of what we think we have found out for ourselves.
Again from Testimony: A Philosophical Study:
Sometimes, however, what others tell us is important as corroboration of what we have already found out (or think we have found out) for ourselves. The Scottish philosopher Thomas Reid makes this point in connection with mathematical research in the belief that, if it applies to the science 'in which, of all sciences, authority is acknowledged to have least weight', it will be even more significant in other areas of thought and practice. Reid is worth quoting in full:
"Suppose a mathematician has made a discovery in that science, which he thinks important; that he has put his demonstration in just order; and, after examining it with an attentive eye, has found no flaw in it; I would ask, Will there not be still in his breast some diffidence, some jealousy lest the ardour of invention may have made him overlook some false step? This must be granted."
"He commits his demonstration to the examination of a mathematical friend, whom he esteems a competent judge, and waits with impatience the issue of his judgement. Here I would ask again, Whether the verdict of his friend, according as it has been favourable or unfavourable, will not greatly increase or diminish his confidence in his own judgement? Most certain it will and it ought."
"If the judgement of his friend agrees with his own, especially if it be confirmed by two or three able judges, he rests secure of his discovery without further examination; but if it be unfavourable, he is brought back into a kind of suspense, until the part that is suspected undergoes a new and a more rigorous examination."
[Author footnote]: It is interesting to contrast Reid's attitude with Descartes's. In the Discourse on the Method, Descartes says in discussing the influence of custom and example upon belief, 'And yet a majority vote is worthless as a proof of truths that are at all difficult to discover; for a single man is much more likely to hit upon them than a group of people' . . . The confident individualism of this passage will be relevant to my discussion of the influences of individualist ideology upon the neglect of testimony. Descartes's thought here is not only at odds with the (surely genuine) phenomenon to which Reid draws attention but also with the facts of scientific co-operation and mutual dependency in the uncovering of truths that are (often extremely) difficult to discover.
