Testimony
There is no species of reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men.
Again from Testimony: A Philosophical Study. It's important to understand, when reading the quote below, that this book was first published in 1992 (before internet for the masses). It's also important to understand that the existence of the internet doesn't change the idea below at all.
We must confront the suggestion that the neglect of testimony is warranted by the fact that it really plays an insignificant, or not very significant, role in the formation of reasonable belief. I shall deal with this suggestion by parable; the parable will be narrated in the first person but is meant to reflect our common plight.
I am visiting a foreign city that is new to me—Amsterdam will do. When I arrive at my hotel I am asked to fill in a form giving my name, age, date of birth, citizenship, passport number, and so on, all of which is accepted by the hotel clerk as true because I say it is and will be accepted by others as true because he says that I say it . . . More interestingly still, a good deal of the information that I give so confidently and authoritatively is accepted as true by me on the word of others. That I am so many years old; that I was born on such and such a date; that number H11200 does indeed correspond to the number the Australian passport authorities have in their files—none of these are facts of my individual observation or memory or inference from them. They are based, sometimes in a complex way, on the word of others.
My first morning in Amsterdam I wake uncertain of the time and ring the hotel clerk to discover the hour, accepting the testimony of the voice just as I would accept the institutional testimony of a clock or watch; being early for breakfast I read a paperback history book I have brought with me which contains all manner of factual claims that neither I nor the writer can support by personal observation or memory or by deduction from either: the deeds of a man called Napoleon Bonaparte who is supposed to have done all manner of astonishing things more than 150 years ago, many of his exploits being performed in places neither I, nor even perhaps the author, has ever visited and the reality of which is accepted on the word of others. Indeed, spurred to geographical thoughts, I reflect that on arriving at a strange airport a day or so earlier I had only the aircrew's word that this was Amsterdam, although since then there has been much else in the way of testimony to support their claim. Venturing forth from my hotel I consult a map and commit myself once more to a trust in my fellow human beings, just as I do moments later when I buy a copy of The Times and read about a military coup in Spain, an election campaign in Britain, an assassination in France, and a new development in medical science. The fable could be extended but I suspect that enough has been said to deal, at least in a preliminary way, with the suggestion that the neglect of testimony is justified by its insignificance in the formation of reasonable belief. No wonder that David Hume, who is one of the few philosophers to discuss the topic seriously, says of testimony, 'there is no species of reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men and the reports of eye-witnesses and spectators'.
