In honoring Stephen Toulmin as the Jefferson Lecturer in the Humanities, the Endowment honors a proponent of the high humanism of the sixteenth century, a partisan of Montaigne, of Erasmus, and of other wide-ranging souls for whom all of life was interesting and fair game for reflection and comment. Understanding Toulmin's intellectual temper requires some account of why the sixteenth century, with it passions for the varieties of human experience, its Humanitas, should be revalued as the wellspring and model of modern science, rather than the seventeenth, the canonical century of scientific revolution and of its acknowledged giants: Descartes, Galileo, Newton.

As someone who has known Stephen Toulmin since 1965 -- and far longer than that intellectually through his work -- I would characterize him as an odd duck. He is odd because elusive, not elusive in the sense that he attempts to elude, but in the crotchety, disciplinary, academic sense that he doesn't seem to fit into our crotchety, disciplinary, academic molds. I would call him a philosopher of science, but only if I am allowed to construe science in its broadest senses, as reasoned inquiry into any subject whatever by whatever means offer fluency to our queries and cogency to our practices.

By focusing on Toulmin as a philosopher of science, this inclusive sense of the term offers a distinct advantage and permits an economy of means otherwise not available. His intellectual career is a daunting one if one has to cope serially with Toulmin the natural philosopher, Toulmin the ethical theorist, Toulmin the philosopher of clinical medical practice, Toulmin the theorist of rhetoric, Toulmin the historian of concepts, Toulmin the virtuoso of cognitive psychology, Toulmin the historical sociologist of the interface between science and politics, Toulmin the student of Wittgenstein, Toulmin the historian of the physical sciences, and of evolutionary biology, and of medicine, Toulmin the philosopher of practical reason and of rhetoric, Toulmin the culture historian.

The range makes people nervous, particularly academics. Among us, a plurality of interests is as suspect intellectually as a plurality of worlds would be ontologically or a plurality of faiths theologically. True, as astute a commentator on the world of learning and of logic as Professor W. V. O. Quine has remarked that "the divisions of the universe are not the same as the divisions of the university." Yet, it is a fact -- a Toulminesque fact -- about the universes we construct that they tend to take on the dimensions and features of our university departments. Though it may appear that we arrange our learned disciplines to reflect the way the world is, it is rather the case historically that we have construed the world in the image of our disciplines. If we admit all the multiple Toulmins into one room, we may be making the mistake of imposing the divisions of the university, its sacrosanct and separate disciplinary partitions, upon our hapless subject.

The truth is, however, that for Toulmin, the different disciplines, and even the alternative methods within a discipline, are emblematic of pluriversity, to adapt William James's term. Different "worlds" each call for methods of inquiry appropriate to the different subjects under consideration, the different Lebensformen that prevail. In this sense, the "scatter" of Toulmin's varied works, the range of disciplines his scholarship has addressed, reappears as the many-sided application of a coherent program: one which insists that theory and method in the sciences have their origins and are to be understood in the variety of human practices and interests that constitute these sciences, that is to say, contextually and historically. Each inquiry, each subject, each discipline has its distinctive parameters, its ways of being grasped. It is this tolerance of their differences, this concern for the varieties of reason, that marks Toulmin's approach to the sciences and makes him an arch critic of the Platonic essentialism which argues for a unified "science" and a unitary scientific method.

His openness to the variety of reason have taken Toulmin on an odyssey through strange seas and distant intellectual climes.

Some of this assuredly goes back to Ludwig Wittgenstein, whose student Toulmin was during Wittgenstein's last years at Cambridge. Some of it is articulated in Aristotle's Nicomachean Ethics, which Toulmin often notes: "[I]t is the mark of an educated man to look for precision in each class of things just so far as the nature of the subject admits; it is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician scientific proofs." Some of it is expressed in the skeptical and tolerant reasonableness of Montaigne; and some of it, more recently, in the critique of logical positivism and logical empiricism, which has eventuated in the contemporary "post-positivist" philosophies of science which Toulmin presaged in his very early work -- in The Philosophy of Science: An Introduction (1953), The Uses of Argument (1958) and Foresight and Understanding (1961).

If Toulmin insists that we need to situate a work or a practice in its context in order to understand it, then on the methodological principle that "turnabout is fair play," his own project has to be situated in the context of contemporary philosophy of science. I can do this only in the broadest strokes here, but it may help one to understand the striking triple role Toulmin plays in this conceptual drama: He is participant/critic/ historian all at once.

Twentieth-century philosophy of science began with a mixed conceptual heritage from the nineteenth. From the work of William Whewell and his Philosophy of the Inductive Sciences, John Stuart Mill and System of Logic, and the influence of the histories and philosophies of the physical sciences (Auguste Comte, Ernst Mach, Pierre Duhem among others), the philosophy of science emerged with two distinctive and sometimes opposed features: on the one hand, a strong demarcation of science from non-science and the unscientific -- from metaphysics and theology, in its characteristic version. This had two aspects: (1) an empirical/ experimental criterion of the meaning of scientific statements ("if it can't be interpreted in terms of observation and measurement, then it's metaphysics and not science"); (2) a logical-mathematical criterion of scientific inference ("if it can't be reconstructed in the form of deductive argument, it's not rational, not yet the language of science proper") and of scientific theory ("if it can't -- in principle -- be cast in the form of an axiomatic system, then it is theoretically defective or incomplete"). Thus, nineteenth- century positivism may be summarized, in one of its aspects, as empiricist in content and logical in form.

On the other hand, Comte, Mill, and others in the very same "positivist" camp proposed various classifications of the sciences which made distinctions not only among the subject matters (e.g., of the astronomical, physical, chemical, biological, and social sciences) but also among the method appropriate for each. This pluralism of method did not yet entail a hierarchy, where all the so-called lower sciences would strive to attain the condition of the "highest" mathematico-deductive science -- in Comte's case, astronomy. Given this rather loose and friendly nineteenth-century positivism, with its enthusiasm for the social sciences and its concern with human happiness, liberty, ethics, political democracy, socialism, the emancipation of women, and even, with Comte, the "religion of humanity," where exactly did the impetus for reduction to one paradigmatic science come from? How did the conversion take place to the notion of a unified science as a hypothetico-deductive structure based on mathematically expressible measurement? When did mathematical physics -- or more narrowly, classical mechanics -- become the condition to which all the sciences had to strive, if they were to become more "mature?" Most immediately, this can be explained as the story of the development of the logical-positivist model of scientific explanation. This is a complex phenomenon, easy to misconstrue if one regards it as some autonomous conceptual history taking place in the rarefied precincts of the scientific and philosophical intelligentsia of Mitteleuropa. In fact, twentieth-century positivism was a social and political movement as much as a scientific and philosophical one. It needs to be understood against the background not only of the new science, but also of Viennese culture and politics, of the apotheosis of the French secular Enlightenment of the eighteenth century which was revived in the 1920s for the renewed battle against clericalism, obscurantism, and superstition, and against the earliest manifestations of Austrian fascism and anti-semitism in the University of Vienna itself.

The critique of this positivism and its attempt at the "logical reconstruction of science" proceeded in large part in a context-free way, as an internal critique of the logical, linguistic, and scientific arguments: about explanation and prediction, the nature of laws, and the problems of observation and measurement as the evidentiary ground and test of hypotheses. Only slowly did the questions shift from internal critique within the system of thought to external critique of the very account of science itself presupposed by the positivists. In order to effect this shift, one had to see differently, to take into account the practices and languages of the actual scientific community, both in its contemporary and historical modes.

Toulmin had the arrogance, the wit, the style, and the scientific training to question the received view. Worse yet, he had the historical grasp and the philosophic breadth to trace it to its origins, to the contexts in which it arose; and he had the further chutzpah to offer an account of why it arose when it did historically, what its social-political impetus was. He was not prescient, nor did he do this all at once. But here lies the vivid continuity of his project.

In 1953, Toulmin published one of the earliest contemporary works in this field -- The Philosophy of Science: An Introduction. It was perhaps the first of its generation to emphasize how working physicists used theoretical and mathematical terms -- their trade language -- and how this related to their practices and needed to be understood in those terms. True, Rudolf Carnap had pointed to the practical contexts of the choice of language-frameworks; and Karl Popper had argued that it was a matter of practical social psychology as to what a scientific community would choose to count as "basic statements" -- those rock-bottom expressions representing what the scientist uses as the language of direct reference in a particular discipline.

It may have been the influence of Wittgenstein, or of the socially and pragmatically oriented Otto Neurath, that forced these considerations of context upon Carnap and Popper (who dissociated himself from Vienna circle positivism on other grounds). But one certainly could not say that either history or context was a strong suit in the epistemology or the methodology proposed by the Viennese; and it was all but anathema to their British and American followers.

In the early fifties, Toulmin's critique of acontextual, ahistorical formalism in the philosophy of science was barely noted. He had spoken too soon. Toulmin's own account of this development is wryly modest. In his recent work, Cosmopolis: The Hidden Agenda of Modernity (1989), he writes of the transition from logical positivism:

The tide turned in the 1950s. A new generation of philosophers, with previous experience in the natural science rather than in pure mathematics or symbolic logic, wrote about science in a new style: less exclusively logical, and more open to historical issues.

This novel philosophy of science was a challenge to the orthodoxy of logical empiricism. Chronicling its early years, Theodore Kisiel finds its origin in my 1953 book, The Philosophy of Science; but, undoubtedly, the most influential document of the movement was Thomas S. Kuhn's book, The Structure of Scientific Revolutions, published in 1962.

Are we to abandon sweet, pure reason for the charms of the locals? Is that Toulmin's proposal? Hardly. What's asked for is a more open appreciation of the uses of reason and of argument, a less authoritarian insistence on the hegemony of one form of rationality over all others, and a proper valuation of the complexity and many-sidedness of life, which occupies us with considerations of the practical, the prudential, the questions of right and wrong, better and worse, health and illness -- all of which require of us that we be responsible to think things through, that we give good reasons for our choices, or at least try to do so.

In Cosmopolis, Toulmin offers a revelatory contrast between Montaigne's openness and Descartes's closetedness (in Descartes's phrase, larvatus prodeo, "I present myself masked.") These are not seen simply as personal traits of character. Rather, Toulmin reconstructs the transformation of European society after the assassination of Henry of Navarre in the streets of Paris, the Thirty Years' War, and the Revocation of the Edict of Nantes and the end of the relative tolerance which it had represented. The practices of reason, the hunger for an overweening universality and cosmic certainty in the face of these traumatic disruptions -- all of these are offered to us as suggestions for how we are to understand conceptual change. It is not a matter of some detached, internal, and autonomous dialectic of ideas; nor, on the other hand, is it simply the ideational reflex of world events and social practices. It is a more nuanced matter, in which all these features are left in play in the reconstruction of the living contexts of philosophy and science.

A decades-long project of this sort is heavy business. It doesn't lend itself to headline presentation, nor to quick summary or simplification. Even Wittgenstein's suggestive remark about forms of language and forms of life, however much it may inform us about the Austro-German Wittgenstein that the Anglo-Americans tended to leave behind, doesn't yet capture the subtlety and detail of Toulmin's project. Nor does it serve as the source of Toulmin's Praxisbezogniss. Toulmin has characterized his relationship to his teacher in an interesting way, since it speaks to the persuasions of the young, pre-Cambridge Toulmin. "Going to Wittgenstein's classes," he says, "gave me the courage of my own prior convictions."

Fortunately, Toulmin makes it easier for us to follow his elaborated project through his many books, by the grace of his writing and the vividness of his account of philosophical and scientific ideas and movements. His is a lithe prose, with almost a melodic line. A review essay by Toulmin of L. S. Vygotsky's work in cognitive psychology appeared some years ago in the New York Review of Books. The editor had titled it in reference to Vygotsky: "The Mozart of Psychology." Given my admiration for Mozart, no one deserves to be called "the Mozart" of anything. There is only one. Yet, one may be permitted a light metaphorical extension of the aura of Mozart's work, by the use of the term "mozartian." Consider it an act of critical temerity on my part, then, when I choose to suggest that Toulmin's prose, at its best and in its high moments, is, well, OK, mozartian.

Marx W. Wartofsky was Distinguished Professor of Philosophy at City University of New York and taught at Baruch College and the CUNY Graduate Center.

He was the author of Conceptual Foundations of Scientific Thought (1968), Feuerbach (1977), and Models: Representation and the Scientific Understanding (1979), and edited the Philosophical Forum, a quarterly journal. He died unexpectedly earlier this month, just as he completed this appreciation.