Tuesday, April 22, 2008

Anecdotal Evidence and Science

Luca Turin says in The Secret of Scent:

“It has been said, correctly in my opinion, that theories define facts as much as the other way around. ... Anecdotal evidence has sort of a slippery, jelly-like quality to it, and theories are needed to congeal the stuff together into single, solid facts. 'Anecdotal' is often used as a pejorative term in scientific circles, meaning unreliable. In practice it often means isolated, and therefore hard to assess.”

“Think of a new field of science as a large jigsaw puzzle. Pieces are discovered one by one, and at first they are unlikely to fit together to make a picture. Things can look distinctly unpromising, sometimes for decades. But if you can bear the pain of feeling stupid and the humiliation of being wrong, anecdotal evidence is the call of the wild, the surest sign of the undiscovered.”

“Columbus set sail on the basis of anecdotal evidence. The Mayan hieroglyphs were deciphered using anecdotal evidence. Life-saving remedies based on plants, such as aspirin and digitalis, were found by scientists who paid attention to anecdotal evidence.”

“Scientific problems typically go through three phases. In the first phase, a few bold explorers discover a new land and map out its basic features. In the second phase, boatloads of immigrant scientists arrive and colonize the land. In the third phase, statues are erected on town squares, sometimes to the original discoverers, more often to the able administrators who built the roads and railways.”

Source: Luca Turin, The Secret of Scent, HarperCollins, 2006, p. 108. First spotted on Delancey Place, 23 May 2007, which makes available, ‘eclectic excerpts delivered to your email daily.”

Image: “Think of a new field of science as a large jigsaw puzzle.”