derivative work

random quotes ... to amuse, inspire, enrage:
  We believe most of what we believe about the world because others have told us to. Reliance upon the authority of experts, and upon the testimony of ordinary people, is the stuff of which worldviews are made. In fact, the more educated we become, the more our beliefs come to us at second hand. A person who believes only those propositions for which he can provide full sensory or theoretical justification will know almost nothing about the world; that is, if he is not swiftly killed by his own ignorance. How do you know that falling from a great height is hazardous to your health? Unless you have witnessed someone die in this way, you have adopted this belief on the authority of others. This is not a problem. Life is too short, and the world too complex, for any of us to go it alone in epistemological terms. We are ever reliant on the intelligence and accuracy, if not the kindness, of strangers.

This does not suggest, however, that all forms of authority are valid; nor does it suggest that even the best authorities will always prove reliable. There are good arguments and bad ones, precise observations and imprecise ones; and each of us has to be the final judge of whether or not it is reasonable to adopt a given belief about the world.