Obituary: Professor Thomas S. Kuhn

Article excerpt

Thomas S. Kuhn's writing, though not voluminous, had a major impact on how we think about the nature of science, particularly its development. Perhaps the most widely used (and some would say, most frequently misunderstood) concept in discussions of the growth and "progress" of the sciences is the word "paradigm". It appeared as a way of making clear the nature of historical changes in the content and methods of the sciences in Kuhn's famous book The Structure of Scientific Revolutions, first published in 1962 as a volume in the ambitious Encyclopedia of the Unified Sciences, from Chicago University Press.

Though there had been dissident voices, it had been taken for granted that the sciences grew by the accumulation of accredited "facts". Adding new facts had no effect on those already accumulated. Laws of nature were drawn from regularities among these facts by induction.

Drawing on the pioneering work of Ludwik Fleck, Kuhn proposed a very different picture. He was struck by the wholesale transformation that took place in the beliefs of a scientific community when some revolutionary development occurred. In giving up an earth-centred picture of the solar system for a sun-centred cosmology, the astronomers of the 16th century not only changed the factual basis of astronomy but the entire framework of thought in which the old beliefs had been framed. This transformation he called a paradigm shift. It was so drastic a change that Kuhn sometimes used the metaphor of "different worlds" to express the radical shift in perspective that a paradigm change brought about. It was almost as if those who lived within the old paradigm and those in the new were cut off from one another by a chasm of mutual unintelligibility.

The key notion of paradigm did duty, in Kuhn's most influential writings, for a variety of features of the coherent world view of a community of scientists. These included a general conception of the nature of the material world, a cluster of accredited methods and a concrete exemplar of good work to which aspirants to membership of a scientific circle could be directed for guidance. Despite philosophical criticisms of the details of Kuhn's use of the term "paradigm", it has continued to be a valuable tool for characterising large-scale changes in some scientific field.

How did paradigm change occur? How did one paradigm come to replace another, creating a new scientific community? The rational picture of a logically ordered accumulation of facts inductively giving rise to laws left no room for what had evidently happened in history. Paradigm change, or "revolutionary science" as Kuhn called it, was more a matter of persuasion, personal influence, indirect influences from social changes and even propaganda, than it was a matter of logic. Once a revolution had occurred, then the pattern of "normal science", the painstaking accumulation of detailed knowledge within the new paradigm, was resumed.

Kuhn's work was so influential in so many fields partly because of his historical verisimilitude, and partly because, in the spirit of the times, it opened a space for the sociology of knowledge to find a serious role in philosophy of science, hitherto very much the province of those with a predominantly logical interest. …