http://www.theapj.com/the-kuzari-principle-2/
What we call the Kuzari Principle is what I italicized in the quotation: Personal experience is equal to uninterrupted tradition as a ground for belief. Surely the principle is in need of some refinement, but the basic idea is true. The scientific community doesn’t feel the need to repeat every experiment ever conducted before accepting the relevant findings for themselves. If there wasn’t a modicum of trust given to the testimony of past scientists about their findings, then we could never move on, because we’d first of all have to repeat the entire history of science in our own laboratories. If we take the best elements of these medieval arguments and try to fashion them into something formal, and prima facie worth considering, we end up with something like the following:
If a reliable witness, called person-y, witnesses an event, event-x, and an uninterrupted chain of reliable sources passes on person-y’s testimony, even over many years, then, given certain provisos about the make-up of the chain, about person-y and about the reported circumstances of the original observation, we have good reason to believe that event-x transpired.
(KP2) The epistemic warrant provided by such a chain increases with the number of reliable observers in the chain who claim to have witnessed the event themselves.