Thursday, May 28, 2009

Paradigms in science and the case of Paul Dirac

British physicist David Tyler writes about Nobelist Dirac, pictured above: :
It is good advice to be wary of anyone purporting to represent the consensus in science. Those who speak the loudest about scientific consensus are often advancing other agendas. A good example can be derived from what people say about the 'scientific method'. Anyone practising science needs to know what it is, but in the real world, the progress of science often departs from the norm. Paul Dirac was a case in point. He was a theoretical physicist at Cambridge University who, in 1928, developed the maths that described the quantum behaviour of electrons. This led to the conclusion that it must be possible for an electron to have a positive charge. Later, Dirac described it as an "anti-electron" and when it was discovered in 1932 it was named the positron. The following year, Dirac received the Nobel Prize for his work. The first biography of this genius has been published recently and an informative review appears in the current Nature.

Several characteristics of Dirac's work do not fit well with the consensus way of doing science. First, Dirac was a pure theoretician. He was not an experimentalist (although, later in life, this changed). He did not show any interest in stimulating a quest to find the positron. "Although he commented that it could be made transiently in experiments, he was surprisingly circumspect, more concerned with the difficulties of detection than the inevitability of its existence. He made no suggestion as to how experimentalists might make it, or recognize it. He was away in the United States later that year when Robert Millikan gave a talk at the University of Cambridge, UK, showing Anderson's images of particle tracks from cosmic rays - including some that looked like those of electrons but which curved the wrong way in a magnetic field. No one associated these tracks with Dirac's holes."
For more, go here.