Stephen Toulmin 1922-2009 was a British-born philosopher, heavily influenced by Wittgenstein but also a full bottle on the history and philosophy of science. In 1972 he published Human Understanding: General Introduction and Part I: The Collective Use and Evolution of Concepts. He planned to follow with two more parts at two-year intervals – Part II “The Individual Grasp and Development of Concepts” and Part III “The Rational Adequacy and Appraisal of Concepts”. I don’t think he produced the second and third parts as planned although he did write more books, I will have to do some research on that.
A computer science student in Adelaide 1967 showed me Toulmin’s early book Foresight and Understanding and this was probably the first serious philosophy book that I read before discovering Popper the following year. It stayed with me when the student became disenchanted with his studies and left. I spent some time reading it and thinking about his arguments although with little benefit that I recall.
Over the years I have seen some of his work, he never appeared to be keen on Popper although they are both credited among the people who revived evolutionary epistemology. He was critical of Kuhn in the debate with Popper at the 1965 Bedford College Conference – see his contribution to the Lakatos and Musgrave (eds) volume.
In this book Human Understanding he comes out swinging against Kuhn! His most powerful criticism is that Kuhn misread his own historical studies of the Copernican and the Einsteinian revolutions when he used them as the basis of his story about normal science, paradigms and scientific revolutions. He came very close to claiming outright fraud by Kuhn in his misrepresentation of the historical record.
Kuhn’s original story ran along the lines that scientists diligently and uncritically cleave to the ruling paradigm until so many anomalies accumulate that they cannot be ignored and then there is a rapid and irrational or non-rational revolution when the field or at least the younger and more agile scientists switch to work on the new paradigm. The protagonists of the old and the new are divided by their assumptions, their perceptions and their terminology so they cannot effectively communicate to manage a rational transition to the new way of thinking. Someone wrote “funeral by funeral, the old paradigm fades away” or words to that effect.
Over some years Kuhn modified that position until it became almost unrecognizable although the Kuhnian zealots did not really pay much attention to the more reasonable and no longer exiting or revolution version of the master.
I think Toulmin’s criticism is devastating although he allowed that Kuhn’s work did have the merit of demonstrating the failure of the logical positivists and logical empiricists.
Before turning to the critique of Kuhn I will note Toulmin’s larger game plan to put philosophy back in touch with the real world of science. That means getting away from the obsession with the formalism of the logical positivists and the logical empiricists which hogtied the mainstream of the philosophy of science since the 1930s when the positivists created the philosophy of science as a professionalised academic specialty.
“This thesis can be summed up in a single, deeply held conviction: that, in science and philosophy alike, an exclusive preoccupation with logical systematicity (sic) has been destructive of both historical understanding and rational criticism. Men demonstrate their rationality, not by ordering their concepts and beliefs in tidy formal structures, but by their preparedness to respond to novel situations with open minds – acknowledging the shortcomings of their previous procedures and moving beyond them” (Preface vii).
He noted the persistence of the seventeenth century presuppositions regarding the Euclidean model of certainty, so “A properly formulated system of scientific concepts could claim intellectual authority on condition that it measured up to the standards of rigour and certainty set by geometry…Claims to true knowledge must be backed either by incorrigible, self-authenticating data [Empiricism] or by arguments as complete and rigorous as those of pure mathematics [Rationalism] and preferably by both” (18).
This meant that there could be no such thing as conjectural knowledge.
Faced with the intractable problems with actual empirical knowledge – uncertainty of sense perception, interpretation of data, the problem of induction, epistemologists attempted to discover what kind of conditions could enable other sciences to achieve something like the authority of the “formal, demonstrative sciences”.
Eventually that became for many the “very defining task of philosophy”, to “find additional principles or premises which would bring arguments from substantial fields of inquiry up to the mathematical ideal. The alternative course, of challenging the formal ideal itself, seemed to them a betrayal of philosophy: abandoning all philosophical claims to ‘rational certainty’ and opening the gates to sceptics” (19)
That is part of the background where Toulmin sets the stage to present his alternative to the “rational certainty” or “justified true belief” approach to rationality, scientific practice and the study of the growth of knowledge.
Criticism of Kuhn on paradigms and revolutions
His criticism of Kuhn is important because Kuhn was the major influence in promoting a very different path from the ruling tradition of empiricism/positivism but for Toulmin that is no better than the old school. He has parted company with the logicism and formalism of the positivists/empiricists and also Popper who he aggregated with them.
Toulmin disputed the key features of Kuhn’s arguments in The Structure (1962) and he disputed them on the basis of Kuhn’s own cases, first Copernicus and the other the dethroning of Newton by Einstein. First the Copernican revolution.
“As his historical analysis makes clear the so-called ‘Copernican Revolution’ took a century and a half to complete and it was agued every step of the way…however radical the resulting changes in physical and astronomical ideas and theories it was the outcome of a continuing rational discussion and it implied no comparable break in the intellectual methods of physics and astronomy.” (105) He went on to say that the scientists who were trained in the pre-Copernican system did not to be forced or cajoled into changing their minds, there was no need for a quasi-religious conversion because the evidence and the arguments were there to convince them over a period of time.
The same process occurred in the ascent of Einstein’s revolution. Far from failure of communication between rival schools there was a period of disputation over several decades and some scientists accepted the new physics more willingly than others but eventually the evidence and arguments carried the day. Toulmin noted that many theoretical physicists worked through the years from 1890 to 1930 and they lived through the changeover. Their testimony should indicate whether there was any breakdown in communication of the kind which was supposed to occur in a Kuhnian revolution. However, contrary to the “paradigm change” account: “After the event many of them explained very articulatedly the considerations which prompted their decision to switch from a classical to a relativistic position; and they reported these considerations as being the reasons which justified their change, not merely the motives which caused it. They did not use the language of conversion “ ‘I can no longer see Nature as I did before…’ Nor did they treat it as the outcome of non-rational or causal influences: ‘Einstein was so very persuasive…’ or ‘I found myself changing without knowing why…’ or ‘it was as much as my job was worth…’. Rather they presented the arguments that sanctioned their change of theoretical standpoint” (104).
Although this book appeared in 1972 it seems to have had no impact on Kuhn’s profile or indeed any profile of its own in the HPS literature. It is a little strange that I did not encounter these arguments or references to this book by Toulmin during the time I studied the history and philosophy of science for a Master of Science, not to mention all the other HPS literature that I consumed since the 1970s. The reference to Human Understanding came in a piece by Terrence Hutchinson in The Journal of Economic Methodology. He has been credited or blamed for introducing Popper to the economists with a book in 1938 (although he took a more positivist line and the Popper bits were a few sentences in German in the notes at the back of the book). Anyway it was a happy accident that I followed up his more recent work in several books and articles in the literature on the philosophy and methodology of economics.