JARS v50n4 - Commentary: The Paradigm Bell

Commentary: The Paradigm Bell
Dr. M.J. Harvey
Victoria, British Columbia

On the evening of 8 May 1996 I was sitting in the Corran Halls Convention Centre in Oban when I heard the ding of a bell. Good heavens, I thought, that is the paradigm bell. Let me explain.
A paradigm (para-dime) is a word popularized by Thomas Kuhn, a philosopher of science. He used it to mean a set of ideas generally accepted by a group of people and used as the foundation for their belief system.
For instance, during much of the mediaeval period there was the paradigm that the Earth was flat. This was perfectly sensible since before gravity was postulated the ocean water would have been expected to drain off the bottom if the Earth were a sphere. Then some people suggested that the Earth might be round. This led to a period of confusion. Finally Magellan went on a journey, arriving back at his starting point without doubling back on his track and everyone then believed the Earth-as-a-sphere concept. Well, nearly everyone. Such a change in belief is called a paradigm shift.
In the case of rhododendrons, the two paradigms are much more trivial, although I have heard people get fairly hot under the collar about them. The initial paradigm resulted from a flood of newly discovered species from the northern Indian-western China region, starting in the late 19th century. To help classify these, Professor Bayley Balfour in Edinburgh put together groups of species that he called "series." This classification came to be known as the Balfourian System. However, note that even he regarded this system as temporary. Unfortunately he died before he could revise it.
The second paradigm also partly resulted from a flood of new species, this time from Southeast Asia. Hermann Sleumer took on the task of describing them.
Starting in 1937, Sleumer found that Balfour's series, devised basically for specimens in cultivation in Britain, were quite inadequate for grouping the additional species. Accordingly he devised an alternative system, publishing the first version in German in 1949. (The work had been delayed by World War II and particularly by the 1943 firebombing of the Natural History Museum in Berlin when all the Rhododendron herbarium specimens and Sleumer's manuscripts were destroyed.) This was the start of the new paradigm.
However, acceptance of the Sleumer classification has been very slow. This was partly because of the abstruse nature of scientific writing (it is quite unreadable), partly because it was for long only available in German, but largely, I think, because we tend to cling to the old and the familiar.
The Royal Botanic Garden, Edinburgh, has led the way in producing a revision of the genus broadly based on Sleumer's ideas. This revision is now available in five parts. It is the result of the collaboration of many people including J. Cullen, D.F. Chamberlain, W.R. and M.N. Philipson, K.A. Kron, W.S. Judd and S.J. Roe.
The first volume of the revision was written by James Cullen, who was invited some time in the 1980s to give a talk on the new classification at an ARS meeting. I was not present but a friend of mine reported, somewhat shocked, that at the end of the talk there were some boos from the audience. The paradigm definitely had not shifted at that time.
The importance of the ARS Annual Convention held in Oban, Scotland, 1996, I like to think was embodied in the presentation to David Chamberlain of the Society's Gold Medal for his contributions to Rhododendron classification. It represented the formal acceptance by the Society of the revision process started by Hermann Sleumer in 1949. The paradigm had finally switched. It took 47 years.
It is rare for the time at which a paradigm shift takes place to be precisely recorded, but I think it happened at the point when President Spady passed the medal to David Chamberlain. The "paradigm bell" was of course purely a figment of my imagination, but I think the event and its significance should be noted by members. Congratulations, David.
Oh, by the way, some people still believe in a flat Earth.