Experience is important for the development of cognitive authority. Karin Knorr-Cetina talks about the need for scientists to see particular events with their own eyes or to actually place their hands on the apparatus. Charles Boyle apparently set up the vacuum pump as a roving laboratory to give others this same kind of experience and practical authority (see Frohmann's recent work in Library Trends).
There are a few recent events that demostrate this idea. The first involves Pierre Pettigrew's recent trip to Haiti. Pettigrew is the Canadian Foreign Affairs Minister and he traveled to Haiti to "see for himself" the effects of Hurricane Jeane.
The second was recently documented in the NYT. Barstow, Broad, and Gerth ("How the White House Embraced Disputed Arms Intelligence") describe how the US Government made the decision to invade Iraq based on an opinion regarding the use of some--well, lots of--aluminum tubes. A CIA analyst ("Joe") defended the position that the tubes were being used in centrifuges to refine uranium for WMD. Most experts disagreed. The analyst, however, had been a mechanical engineer who had worked at Oak Ridge, Tenn. and had actually operated centrifuges. Even though he was a junior analyst, his body authority--combined, of course, with some fervent political will--led the government to disregard the opinions of world recognized experts who had not actually operated centrifuges.