It is the use of a (usually short) passage, taken from the work of an authority in some field, "which superficially appears to support one's position, but [from which] significant context is omitted and contrary evidence is conveniently ignored."The classic example of quote-mining is the creationist claim that Charles Darwin did not believe that evolution could account for the human eye, which they bolster with the following quote from The Origin of Species (1859):
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.Ok, sounds like Darwin thought evolution explaining the eye was absurd. But here's how the quote appears in context
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of Spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree. When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei ["the voice of the people = the voice of God "], as every philosopher knows, cannot be trusted in science. Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certain the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, should not be considered as subversive of the theory.Obviously, Darwin is in fact expressing the opposite of what creationists who snip the context of the quote suggest. One can see how fundamentally dishonest such a practice is.
Today, PZ Myers directs our attention to an Op-Ed in the New York Times by a scientist who has been quote-mined by global warming skeptics (like Ann Coulter and Michael Crichton) to make the case that the Earth is not warming. Peter Moran, the author of the piece, points out that his work does not suggest that and that he does not dispute global warming.
My research colleagues and I found that from 1996 to 2000, one small, ice-free area of the Antarctic mainland had actually cooled. Our report also analyzed temperatures for the mainland in such a way as to remove the influence of the peninsula warming and found that, from 1966 to 2000, more of the continent had cooled than had warmed. Our summary statement pointed out how the cooling trend posed challenges to models of Antarctic climate and ecosystem change.Although it can result from deliberate dishonesty, quote-mining is primarily an error of methodology. It is a form of "cherry-picking" where a person just looks for information that confirms his/her beliefs, and it results from a disregard for careful consideration of the evidence. Anyone who cares about honest discourse and respecting the intellectual work of others should take care to check their source to see if it says what they think it says before using it to make a case that the quote does not actually make.
Newspaper and television reports focused on this part of the paper. And many news and opinion writers linked our study with another bit of polar research published that month, in Science, showing that part of Antarctica’s ice sheet had been thickening — and erroneously concluded that the earth was not warming at all. “Scientific findings run counter to theory of global warming,” said a headline on an editorial in The San Diego Union-Tribune. One conservative commentator wrote, “It’s ironic that two studies suggesting that a new Ice Age may be under way may end the global warming debate.”
In a rebuttal in The Providence Journal, in Rhode Island, the lead author of the Science paper and I explained that our studies offered no evidence that the earth was cooling. But the misinterpretation had already become legend, and in the four and half years since, it has only grown.