http://www.scientificamerican.com/article.cfm?id=hermits-and-cranks-lesson
How can we tell if someone is a scientific crank? Gardner offers this advice: (1) "First and most important of these traits is that cranks work in almost total isolation from their colleagues." Cranks typically do not understand how the scientific process operates—that they need to try out their ideas on colleagues, attend conferences and publish their hypotheses in peer-reviewed journals before announcing to the world their startling discovery. Of course, when you explain this to them they say that their ideas are too radical for the conservative scientific establishment to accept. (2) "A second characteristic of the pseudo-scientist, which greatly strengthens his isolation, is a tendency toward paranoia," which manifests itself in several ways:
(1) He considers himself a genius. (2) He regards his colleagues, without exception, as ignorant blockheads….(3) He believes himself unjustly persecuted and discriminated against. The recognized societies refuse to let him lecture. The journals reject his papers and either ignore his books or assign them to "enemies" for review. It is all part of a dastardly plot. It never occurs to the crank that this opposition may be due to error in his work….(4) He has strong compulsions to focus his attacks on the greatest scientists and the best-established theories. When Newton was the outstanding name in physics, eccentric works in that science were violently anti-Newton. Today, with Einstein the father-symbol of authority, a crank theory of physics is likely to attack Einstein….(5) He often has a tendency to write in a complex jargon, in many cases making use of terms and phrases he himself has coined.