Critical Thinking After the Second World War

by Michael Boyle

In my first essay on critical thinking, I focused on the period prior to and during the Second World War. In this essay, I wish to follow the narrative into the post-war years, focusing on two somewhat forgotten scholars (at least in philosophy and, more specifically, critical thinking, as taught in philosophy departments in the US): Stephen Toulmin and Chaïm Perelman. As we saw in the earlier piece, the background to the post-war period was the eclipse of propaganda analysis and the emergence of a more abstract and quantitative conception of critical thinking, embodied by the assessment tool developed by Goodwin Watson and his student Edward Glaser, the Watson Critical Thinking Test. This stream would be strongly reinforced in the early 1960’s, by scholars associated with a subfield of the Philosophy of Education, in particular Robert Ennis, perhaps the most influential single figure in post-war critical thinking, at least as it is taught in philosophy courses.

Critical thinking, however, is not only taught in philosophy departments, in free-standing courses, but is also commonly found in the fields of Speech & Communications and English. One of the great ironies in philosophy is that two of the most important scholars to contribute to this other stream were themselves philosophers, but whose contributions remain largely unknown in their home discipline. Both men, Stephen Toulmin and Chaïm Perelman, published their seminal works on argumentation in the same year (1958), both were Europeans, and both were influential largely through the efforts of American speech and communications scholars. My aim, here, is to give a rough overview of both men’s works and briefly sketch out how both challenged the view that rigorous argumentation should be equated with deduction, a view rooted in their understanding of the history of logic in the modern period and their common belief that the traumas and the challenges of the 20th century demanded an expansion of logic to include a broader analysis of everyday argument, beyond deduction.

Toulmin (1922-2009), a British philosopher, who studied under Wittgenstein, taught at Oxford, Leeds, and elsewhere, but spent the bulk of his teaching career in the United States. Following service with SHAEF (Supreme Headquarters Allied Expeditionary Force) during WWII, his first major book argued that ethical arguments are important (and not just expressions of emotion) and that an analysis of how and why they work is crucial. His key work on argumentation, The Uses of Argument, published almost a decade later in 1958, reflects a basic view of philosophy (and later, the history of philosophy) that would remain consistent throughout his career. The essential point of the Uses of Argument is to challenge the view in logic that good reasoning is represented by deductive arguments.  Put very roughly, Toulmin maintained that many of the everyday decisions we make, both as professionals and as ordinary people, have little to do with formal deductive reasoning, but instead involve many varieties of defeasible argumentation.

The most famous (and influential) part of the work is his basic argument structure, now simply called the “Toulmin Model,” which Toulmin suggests is a more helpful way to analyze everyday claims, which often make distinctions that are difficult to capture formally. In this model, one begins by making a claim based on a certain datum/data. These are connected to the claim via what Toulmin calls “warrants,” which are sometimes described as “inference licenses” that permit the move from the data to the claim. These warrants are supported by information that Toulmin calls “backing.” Warrants, since they can operate with different levels of force, sometimes need qualifiers (e.g., the data “probably,” “mostly,” etc. supports the claim, via the warrant). Lastly, circumstances under which the grounds/data do not support the claim are referred to by Toulmin as the “rebuttal” of the claim and constitute exceptions.

Toulmin was initially unaware that he was arguing for elements already found in Aristotle. For example, the data/claim pair is essentially a rhetorical enthymeme (a defeasible, non-theoretical enthymeme) — that is, a non-deductive argument with a number of assumed parts that can be fleshed out, if required. In addition, the warrant and the backing for warrants are not, Toulmin argues, formal, “field-invariant” matters (like the principle of non-contradiction), but are “field-dependent,” given that the relevant information will often come from a distinct discipline (the germ of this idea of field dependency is also found in Aristotle), with its own standards of evidence. What counts as a justification, consequently, may vary accordingly. Toulmin (and Perelmen, as we shall see) believed that we should understand defeasible arguments, not according to a geometrical model, but along a jurisprudential one, insofar as practical reasoning seeks to convince an audience and operates within certain procedural constraints that may vary, depending on what the arguments are about.

Toulmin’s work in the analysis of argument is deeply connected to his scholarly work and reflects a specific interpretation of the history of philosophy and the relationship between theoretical argumentation and practical reasoning. In Toulmin’s view, beginning with Descartes in the 1600’s, the dominant tradition in philosophy has been theoretical, notwithstanding some noteworthy dissenters.  In the centuries that followed, philosophy increasingly eschewed what he saw as four key elements of practical reason: the oral, the particular, the local, and the timely. Influenced by Descartes, argumentation amongst real people, reflecting a sense of history is set aside and written propositions become dominant, with the oral relegated to rhetoric and the local disappearing entirely. The particular, that is to say the classic method of casuistry, which Toulmin believed was crucial to ethical inquiry and which proceeds by way of case-by-case analysis, declined in the Early Modern period.  Timeliness, once seen as inextricably tied to the rational, in fields like law and medicine, increasingly took a back seat, as philosophy followed a universal and abstract path, focusing on what he calls “the permanent.” As to the reasons for this shift, believed that the most important was the fact that the first half of the 17th century was a time of war and chaos, so that timelessness, both scientific and philosophic, was far more attractive than an insistence on the importance of the (often unpleasant) particularities, in which one found oneself.

So, why did Toulmin think it so important that we recover our capacity to analyze arguments in terms of practical reason? As he explained over a quarter-century ago, as modern people, we face three fundamental challenges that will require more dialectical resources than abstract logic can provide: biotechnology, atomic warfare, and the global ecosystem. These challenges, he insists, will have to be confronted in terms that take into consideration human life in all its fullness and breadth and also, in all its particularity.

Baron Chaïm Perelman, born in 1912 and dying in 1984 (he was made a nobleman in 1983), was a Belgian scholar of jurisprudence and a philosopher, who published his seminal work with research assistant Lucie Olbrechts-Tyteca, Traité de l’argumentation – la nouvelle rhétorique, in the same year as Toulmin’s Uses of Argument (1958). Unlike Toulmin’s work, which was for the most part rejected by philosophers, Perelman’s was acknowledged by a substantial section of the discipline in Europe and even garnered accolades from Peter Strawson in Mind, a premiere Anglophone journal of analytic philosophy. It was influential in the United States, particularly at Penn State, ultimately contributing to the establishment of a new philosophy periodical, Philosophy & Rhetoric. Despite this, Perelman’s influence in the United States has been outside of philosophy, particularly with students of communications and rhetoric.

Much like Toulmin’s, at the heart of Perelman’s thought is the idea that good arguments involve more than just formal logic. Also like Toulmin, who began his investigations into argumentation with his early work on ethics, a chief concern of Perelman’s was the fact that the formal deductive model of logic left little room for the analysis of normative arguments, an analysis of which he believed essential, in the context of 20th century history.

Perelman started out as both a law scholar and a philosopher, specializing in Frege. What changed him were his experiences during the Second World War, a brief examination of which is instructive. Following the Nazi invasion and occupation of Belgium, Perelman became a key figure under the Front de l’Indépendance (the main Belgian resistance organization against the Nazis), by helping establish the Comité de Défense de Juifs (CDJ), whose job was to save as many Jews as possible from being deported to the death camps. In addition to this underground work (done under the codename Dumont), he had direct contact with the Nazis, because he was at the same time a leading figure in the Association des Juifs en Belgique (AJB), the group that the Germans dealt with in their administration of the Jewish population in Belgium. He used his official post at the AJB during the occupation, in order to simultaneously carry out his underground resistance activities, supplying the Jewish community with materiel and foodstuffs, as well as acting as a conduit for the funneling of monies from the United States through Switzerland. In the meantime, his wife Fela, an historian and granddaughter of the Grand Rabbi of Lodj, was in charge of a kindergarten (Nos Petits) that protected Jewish youngsters from deportation. After the war, Perelman, who personally knew both David Ben-Gurion and Golda Meir, was closely involved with matters regarding Israel, both before the 1948 independence and after. For her part, his wife Fela was for a time an agent for the Mossad, helping her husband get over 500 refugees through the British blockade of Palestine.

His wartime experiences inspired Perelman to search for a structure of normative arguments, akin to Frege’s logicism project for mathematics. What he uncovered instead was the Western tradition of rhetoric and dialectic, with its origin in Aristotle.

As Perelman scholar David Frank (1) has noted, Perelman realized something that Hannah Arendt would write about in The Origins of Totalitarianism, namely, that inherent to totalitarianism is the following-through of a sort of demented deductive logic (albeit from false premises) that is inherent to ideological movements and which serves both as an excuse and a motivation, as well as providing protection from any disconfirmation, coming from the real world. Arendt puts it this way: “Ideological thinking orders facts into an absolutely logical procedure which starts from an axiomatically accepted premise, deducing everything from it; that is, it proceeds with a consistency that exists nowhere in the realm of reality.” Make no mistake- Perelman believed that formal logic was perfectly legitimate and important. He was, after all, a professor of philosophy at the Free University of Brussels, authoring a textbook on logic and heading both the National Center for Research in Logic and the Center for Philosophy of Law. Nonetheless, Perelman came to believe that formal reasoning alone was insufficient, in the context of what he believed was required of argumentation analysis. And that analysis was important, he thought, to strengthen liberal, pluralist societies in the West and to try and prevent the catastrophe of the Nazi era from reoccurring.

In the book he co-authored with Olbrechts-Tyteca, Traité de l’argumentation, Perelman agreed with Toulmin that the separation of logic and rhetoric begins with Descartes and with the idea that proper logical argumentation should be modeled on geometry.  Also like Toulmin (but much more self-consciously), Perelman argued that his work was an attempt to bring back the Aristotelian view evident in the Topics and the Rhetoric, whereby non-deductive argumentation is to be seen as a valid and important area of inquiry for philosophers, a view which Perelman and Toulmin both argued had prevailed from antiquity through the Renaissance. The task of modern logic, says Perelman, is incomplete, because the tradition following Frege had labored on “the theory of demonstration” but had largely ignored working on the “theory of argumentation.” The goal of his work was to map out a taxonomy of such non-deductive argumentation so as to balance things out.

The basic thrust of Perelman’s work was to analyze how a speaker or writer employing non-deductive arguments gains the “adherence” of his audience. He believed that conceptions of reasonableness could vary between communities, because of their different circumstances, abilities, education, and expertise and thought it possible that one community could recognize the reasonableness of a view held by the other, even if they still disagreed.

In terms of focusing on the audiences and how one convinces them,  Perelman explicitly rejected an analysis of delivery or ornamentation, in order to focus on the part he thought proper to philosophy — the structural aspects of argumentation and how this is connected to the people to whom one is speaking or for whom one is writing. Thus, the audience is front and center for Perelman, partly because he believed that the person engaged in argumentation — from “discussion around the family table” to the public square — depended on “an effective community of mind.” (2)  Moreover, different audiences have different varieties of expertise, so some are more qualified than others to render judgment on various matters. Perelman and Olbrechts-Tyteca go on to discuss how a speaker engages with his audience in terms of figures of speech and the like, the matter of the choice and presentation of data, and they give a taxonomy of different kinds of non-deductive arguments and how and why they work.

Perelman, coming from the direction of philosophy and the perspective of a Frege specialist, wanted to expand the scope of modern logic to include those arguments whose demonstration did not automatically demand the adherence of the audience because of their deductive character, but which were nevertheless essential for human life. These everyday arguments speak to what Perelman elsewhere described as the “reasonable” as opposed to the “rational,” the latter taking as its model mathematics and the former functioning like jurisprudence, insofar as argumentation procedures can be mapped out, procedures followed (ideally at least) to seek answers that are provisional, yet equitable.

Both of these influential figures in 20th Century argument-analysis have been victims of disciplinary segregation. Neither Toulmin nor Perelman are typically even mentioned in critical thinking courses, as they are taught in philosophy departments across the US, much less discussed. Nor do their names commonly occur even in the scholarly literature tied to critical thinking in philosophy. (3) This is despite the fact that both were philosophers in the analytic tradition and despite the fact that Perelman was influential in the founding of a respected philosophy journal, Philosophy & Rhetoric, still published at Penn State. By contrast, in other fields that also deal with matters of critical thinking (at least in terms of argument-analysis), one finds that they are still quite relevant.


(1) Frank’s work is helpful in understanding not only the link between Perelman and American scholars of speech and communication — as well as the connection between Perelman and Arendt — but also in terms of what Frank argues is a clear opposition between the deductive, geometrical model that goes back to Plato and a paratactic model seen most clearly in the Talmud. See Frank’s “The Jewish Countermodel: Talmudic Argumentation, the New Rhetoric Project, and the Classical Tradition of Rhetoric” Journal of Communication & Religion 26 (2003): 163-194; “The New Rhetoric, Judaism, and Post-Enlightenment Thought: The Cultural Origins of Perelmanian Philosophy,” Quarterly Journal of Speech 83(1997): 311-331; “Argumentation Studies in the Wake of The New Rhetoric” Argumentation and Advocacy 40 (Spring 2004): 267-283.

(2) He unpacks this by analyzing the difficulties faced by Alice, in the realm of Wonderland.

(3)  For a fascinating discussion of how logic (especially non-monotonic logic) has caught up with Toulmin, see Johann van Bentham’s “One Logician’s Perspective on Argumentation,” Cogency 1 (Summer 2009): 13-25. Van Bentham, who holds appointments both at Stanford and the University of Amsterdam’s Institute for Logic, Language, and Argumentation, describes the Toulmin Model as “…a rich way of seeing many crucial aspects of ordinary reasoning.” (16)

For more on non-monotonic logic and Toulmin (especially the tricky matter of warrants) see William Keith’s “The Toulmin Model and Non-Monotonic Reasoning,” a paper given at a 2005 McMaster University conference on Toulmin’s The Uses of Argument. The conference papers may be accessed online:







44 responses to “Critical Thinking After the Second World War”

  1. Hi Michael,

    A most interesting article, I was unaware of Perelman before you introduced him and only vaguely aware of Toulmin.

    One thing that concerns me is this:

    What counts as a justification, consequently, may vary accordingly. Toulmin (and Perelmen, as we shall see) believed that we should understand defeasible arguments, not according to a geometrical model, but along a jurisprudential one, insofar as practical reasoning seeks to convince an audience and operates within certain procedural constraints that may vary, depending on what the arguments are about.

    It seems to conflate the task of convincing people that something is true with the problem of demonstrating that something is true.

  2. To think there is a conflation here is to make precisely the mistake that Toulmin, Perelman (and Aristotle) warned against. That’s the whole point of this part:

    “warrant and the backing for warrants are not, Toulmin argues, formal, “field-invariant” matters (like the principle of non-contradiction), but are “field-dependent,” given that the relevant information will often come from a distinct discipline (the germ of this idea of field dependency is also found in Aristotle), with its own standards of evidence. What counts as a justification, consequently, may vary accordingly.”

  3. The key point being that what *counts* as a justification is not topic-neutral in practical reasoning. (And if Wittgenstein is right — it’s not topic-neutral in theoretical reasoning either.)

  4. brodix


    Wouldn’t both amount to a focusing of attention in a particular way, either to convince a particular audience of a course of action, or to extract the logical consequence from a particular premise?

    As such, “extracting the signal from the noise,” though in very different contexts.

    The other side of the coin from this process of defining, would be explaining. In that while definition requires a focus on the specific aspects of a particular sequence, or concept, explaining it requires a much broader view of the context. Which does tend to then obscure or diminish the particular. So an effective presentation, especially one to draw in that broader audience, does require some combination of this process of both expansion, then distillation and as many cycles of this process as either the audience will stand, or the subject requires.

  5. mpboyle56

    Robin Herbert & brodix:

    In terms of the success of an argument, the question of what counts as a justification is key, as DanK pointed out. And what counts depends on what we’re talking about.

    Toulmin notes (in a coauthored textbook on critical thinking that first came out in 1978 and is out of print, with Toulmin as lead author and his ideas as the organizing principle):

    “Just whose agreement is required for the success of any argument, and on what terms, also varies from field to field and from one type of argument to another. In particular, some enterprises rely on achieving consensus between the parties to an argument; others involve adversary procedures, by which general agreement is not required.”

    Examples of the former are natural sciences and of the latter, “judicial argumentation.” Toulmin, et. al. then continue a bit further on:

    “In matters of business and public policy, the situation is different yet again. The required outcome of argumentation is not a simple consensus or a ruling between adversaries, but a practical decision. Rather than expecting to arrive at unanimity about the superior wisdom of any one course of action, it is necessary to balance off rival uncertainties: to weigh prospective gains against prospective losses according to general maxims of political wisdom or financial strategy.”

    Context determines criteria.

    The terms we use to criticize and judge the merits of particular arguments and claims depend on their ‘type’ and so their ‘field.’ Whether it be politics or ethics, science or aesthetics, psychiatry or law, the underlying goals of the human enterprise concerned determine the fundamental context for the arguments and claims in question, and so give them their power to ‘carry conviction,’ by establishing the claims on a secure basis.”

  6. Hi Daniel,

    I am a little confused by that. We can agree that what counts as justification is not topic-neutral, but how does that bear on the distinction between attempts to convince and demonstrating the truth or likelihood of a claim?

    The words ‘seek to convince an audience’ are in the article. What I would suggest *is* field invariant is that the convincingness of an argument is not a guide to whether or nor it is a justification for the claim in question.

    Of course the converse should be true for a suitably qualified audience.

  7. Hi Michael

    Nicely written piece.

    I don’t suppose you know anything about Edmond Goblot whose Traité de logique was very influential in French (and presumably Belgian) education. Perelman refers to him. My interest relates mainly to a controversy between him and his one-time student Louis Rougier.

    Perelman clearly had a much more ambitious agenda than Goblot however – to find a way (as I understand it) of justifying fundamental values. He has these strong intuitions – and he wants to find a way of justifying them retrospectively. But I find his notion of a universal audience (even an imagined one) questionable. Can it do the work he wants it to? I note (for example, in his essay ‘Justice and justification’) that he seems to be relying on (falling back on?) Kant’s categorical imperative.

  8. davidlduffy

    Those in the area of (computer aided) argument mapping frequently mention Toulmin as one precursor eg
    These often overlap with informal logic and nonstandard logics, as Michael mentions.

    I am curious whether people here think such methods are generally useful. John Danaher over at
    frequently uses them. One shortcoming I see is they don’t usually extend to quantified modelling of arguments, as in
    structural equation or causal modelling – eg the logic of a mendelian randomization analysis.

  9. Mike has given you the answer.

  10. mpboyle56


    I am unfamiliar with Goblot and Rougier. The former is mentioned in passing in Perelman’s major work and the latter appears there in a work cited by Perelman (Poincare’s La Valeur de la science), having written the introduction.

    As for the universal audience, Perelman notes that (especially with respect to philosophers), in the course of argumentation, each one addresses himself to a kind of universal audience of his own creation, including thinkers like Kant and Descartes. Kant is seen by Perelman as the paradigmatic modern instance of such an approach, which Perelman traces back to Plato and a theological conception of truth. Perelman argues that we should interrogate both the arguments and the ideas of the particular universal audience that are used in order to understand where the speaker/writer is coming from, since they may vary depending on the individual and most definitely can vary diachronically. He also notes that there is an interdependent relationship between the notions of fact and truth and the universal audience that is conceived of- the facts or truths relied on by the speaker/writer are such because they are presumably accepted by the audience. In discussing the universal audience envisioned by Descartes, Perelman also states the following: “Pareto has made the penetrating observation that the universal consensus invoked is often merely the unwarranted generalization of the individual intuition.” Sometimes, too, Perelman notes that we use the idea of an elite audience separate from a universal one in a sort of hierarchical model, whereby the elite audience constitutes what he calls a vanguard.

    As a biographical note, in terms of Perelman’s historical and sociological approach to the notions of audience and argumentation, one of his major influences was Belgian philosopher Eugene Dupreel, holder of the Logic chair at the University of Brussels.

  11. Hi Mike, that was an interesting essay on a subject that I have very little knowledge, and so no solid opinion or comment.

    I would say that Robin seemed to capture a feeling I had regarding their position. I probably wouldn’t use the term conflate, but it would be close. And so far I am not completely understanding the response to his question. I’m not trying to extend an argument but asking for a more clear explanation (answers from DanK are also welcome).

    I think a good example of something that raises serious questions in my mind was the quote you gave from the book by Toulmin…

    “In matters of business and public policy, the situation is different yet again. The required outcome of argumentation is not a simple consensus or a ruling between adversaries, but a practical decision. Rather than expecting to arrive at unanimity about the superior wisdom of any one course of action, it is necessary to balance off rival uncertainties: to weigh prospective gains against prospective losses according to general maxims of political wisdom or financial strategy.”

    Combined with the concept of “field dependence”, that would seem to suggest questions regarding whether manipulation of stocks, raising the price of HIV medications, and selling bundled junk loans is worthwhile (or will help society) are best left up to experts like hedge fund managers and Goldman Sachs execs who are more intimate with such general maxims and strategies.

    It would be very easy to convince those particular experts on a certain course of action as if it is valid or laudable, and they likely able to convince their allies in government of the same. But I think the answer to those questions may lay outside considerations within that field alone. At the very least they seem to have missed the potential for external biases which can influence a decision within the body of experts.

  12. brodix


    I very much agree, but I was making the very basic point that they are processes of distillation and discrimination; That of extracting the signal from the noise. Yet that still has to take into account where and what the noise is in the first place, the selection of the context to determine the criteria and the ways this broader context will affect what is selected and the ways this layering is navigated.

    The process is not simply basic, but organic, in the sense that nature is constantly expanding the context, i.e. endlessly branching out, then breaking down and coalescing form from this dynamic. As such, it reflects everything from the cycles of the seasons and biological regeneration, to the Greek Year Gods that represented them and were the basis of western culture. Even Christianity reflected this cycle, in the Trinity, though its origins were obscured by a church which assumed its own structural immortality.

    A point I keep raising is that we don’t fully view time relationally. Since we experience reality as flashes of cognition, we think of it as the point of the present moving from past to future events, which physics codifies as measures of duration, but the reality is physical change creating and dissolving these forms, such that they go future to past, while duration is the present, as events come and go.

    To wit, tomorrow becomes yesterday because the earth turns, rather than a physical vector from yesterday to tomorrow.

    For example; In a factory, the product goes start to finish, while the process goes the other direction, consuming raw material and expelling finished product. Similarly, we as individual organisms go from birth to death, i.e., being in the future to being in the past, while the species moves onto new generations and shedding old, i.e., past to future. As our state of consciousness is constantly moving onto new flashes of cognition, as these mental constructs shortly recede into the past.

    Consider free will vs determinism; To will is to determine, so if it were free of input, it would be equally free of output, i.e., consequence. Now events have to occur, in order to be determined, as it would take a view outside of space and time to know all input into an event prior to its occurrence. Which would require knowing the outcomes of all events producing that input, etc. Yet there is no such “God’s eye view,” since a multiplicity of form, information and perspective results in white noise, not omniscience. The noise from which we extracted the particular signal. Order is emergent from the elemental, not descendent from the ideal.

    So in order to effectively focus and present ones argument, it would help to know, not only the particulars of the context, but this larger cyclical dynamic and how both input into the argument and output of result might fit, or whether they do fit into a context that remains dynamic. That’s why I think keeping the basic process in mind would be useful, since any argument exists in a larger context.

    Ideals are perfect form and a useful framing device, but they should not be treated as absolute, which is the elemental, as so frequently happens in debate. Such as religions assuming cultural ideals to be absolute.

    Hope this makes some sense, otherwise I could clarify any details further.

  13. mpboyle56


    “Combined with the concept of “field dependence”, that would seem to suggest questions regarding whether manipulation of stocks, raising the price of HIV medications, and selling bundled junk loans is worthwhile (or will help society) are best left up to experts like hedge fund managers and Goldman Sachs execs who are more intimate with such general maxims and strategies.”

    A hedge-fund manager’s expertise is in making money. Whether the way he makes money is socially beneficial (the superior wisdom of his actions) beyond his bank account is a separate issue (as we have all seen by the recent financial history of the US). If I understand you correctly, part of what you are driving at, when you say the following, is the notion of a conflict between fields and how to resolve them:

    “But I think the answer to those questions may lay outside considerations within that field alone.”

    This involves the issue of relativism, a charge not infrequently leveled at Toulmin. Part of what Toulmin, Perelman, and others force us to confront is what Christian Kock of the University of Amsterdam calls an “incommensurability of warrants.” Kock notes the following (I have provided a link to his helpful paper, in which he supplements both Toulmin and Perelman especially re: decisions concerning actions and policy-making):

    “The idea that good reasons are many kinds of things, while anticipated in 1950 and reiterated to this day, was stated in its most explicit form in The Uses of Argument in 1958. The idea underlies the famous ‘argument model’, whose centerpiece is the notion of ‘warrant’. The main difference between Toulmin’s model and traditional formal models, beginning with the Aristotelian syllogism, is that warrants are not premisses about the issue in question but assumptions we rely on about the kind and degree of argumentative weight we may assign to the grounds offered. And the underlying insight here is precisely that there are, depending on field and context, many kinds and degrees of argumentative weight.

    …there is no necessary, deductive and certain algorithm telling us what is required when a moral or practical choice has grounds that argue for different actions and invoke different warrants or values. However, the existence of incommensurability and optional choices does not mean that we do not weigh alternatives and make choices. We do make choices, and we do so because we have debated reasons and weighed them against each other.

    Rhetoric comes into the picture not just because people want to sway and persuade each other but because people may legitimately have different views of the same matter and prefer different courses of action. When people use rhetoric to try to win each other’s adherence, they do so not just because they want others to comply at any cost (this is the ‘strategic’ definition of rhetoric), but because they may be legitimately convinced that the view they represent is not only an optional one but the preferable one; and their opponents may have the same legitimacy in thinking likewise of their standpoint. So rhetoric exists because it may be legitimate to hold several different views on a matter and because those holding each of these views may legitimately wish to win the adherence of the others.”

    The paper is also found in a helpful volume on Toulmin entitled Arguing on the Toulmin Model: New Essays in Argumentation Analysis and Evaluation, eds. David Hitchcock & Bart Verheij (Springer, 2006): pp. 247-259.

  14. Mike

    Thanks for the response. The points you make on Perelman’s notion of the universal audience are fine, but all seem focussed on descriptive and relativistic aspects. Does he not also (perhaps in later works?) want it to represent something which functions as a kind of actual, usable moral standard, or standard of reasonableness? As such, it looks like a kind of ideal.

    Also, you did not specifically address my point about his apparent commitment to Kant’s categorical imperative.

  15. brodix


    If I may add a couple more ideas for why formal logic and persuasive argument can have different form and function;

    We are raised, as members of a community, to think of good and bad as cosmic ideals, but the reality is they are the basic biological binary code of attraction to the beneficial and repulsion of the detrimental. Consequently what is good for the fox, is bad for the chicken and there is no happy medium where they are both satisfied.

    Now even the most elementary organisms function according to this fact, while to function as a whole, even the most enlightened community needs some fairly well developed general sense of positive and negative. Otherwise it will break apart over the points of disagreement. So this framework is not to be considered objectively, but as sacrosanct, given that each generation has to be taught it as foundational.

    Another idea, which ties into my previous observation about time, is that this view of time means it is an effect of action and what is being measured is frequency. Which makes it similar to temperature, which is a combination of frequency and amplitude.

    Now our brain has two hemispheres; The right, emotional, non-linear side and the left, linear, rational side. I would argue that the rational function is similar to a clock, in that it is sequential, while the emotional side is more of a thermostat, or possibly pressure gauge, in that it functions more in terms of levels of energy or activity. Therefore we tend to equate emotions with concepts like hot, cold, tension, etc.

    Even insects have been shown to have neural thermal and sequential functions. Given organisms exist as singular entities in a non-linear environment, the sequence function would have originated as a navigation tool, then evolved with the mind into a narrative and causal understanding. From this comes the logical paradigm of one event leading to the next, equated with cause and effect. Though they are not necessarily the same. Narrative is sequence, while causality is energy exchange. For example, yesterday doesn’t cause today, in the way a rock hitting water creates ripples. The sun shining on a spinning planet creates the sequence of days. Yet sequence is fundamental to us as individuals, as when it breaks, we are deceased and our energy dissipates back into the context.

    So it is not so much the function of rhetoric to present a logical sequence, but to stir up and focus the emotional energy of the audience, which as it is made up of many individuals, is not fundamentally linear. So it is this accumulation of energy which binds the group into one, then it can be directed as such.

    Witness Donald Trump and how little coherent logic is necessary for the wave he has created from a dissatisfied electorate, yet rational minds wonder what he would do with it, if elected.

  16. mpboyle56


    My apologies if I was unclear or incomplete. Let me beg your indulgence (and that of the readers) and give some quotes from Perelman, with my comments, in order to try and clarify.

    The universal audience is an ideal, and Kant is an exemplar of universality. However, Perelman differs in that he believes that the universal audience which thinkers have in mind is inevitably time-bound and can vary from philosopher to philosopher:

    “To reconcile philosophic claims to rationality with the plurality of philosophic systems, we must recognize that the appeal to reason must be identified not as an appeal to a single truth but instead as an appeal for the adherence of an audience, which can be thought of, after the manner of Kant’s categorical imperative, as encompassing all reasonable and competent men. The characteristic aspect of philosophical controversy and of the history of philosophy can only be understood if the appeal to reason is conceived as an appeal to an ideal audience – which I call the universal audience – whether embodied in God, in all reasonable and competent men, in the man deliberating or in an elite.” Perelman, The New Rhetoric and the Humanities: Essays on Rhetoric and Its Applications (1979), pp. 13-14.

    “Appealing to reason or to a universal audience, the philosopher can, from his point of departure and reasoning, only support theses and argumentations which, even if in fact they are not admitted by everyone, should in his view impose themselves on all competent minds. This is why his discourse is based on common sense and common experience or make a case for truths, facts,
    evidences and necessities which everyone should admit. From this we can see the importance of common principles, notions and common places for philosophical communication. They furnish this communication with the starting points for argumentation. It is important for this purpose to put the accent on the term ‘common’ because it it through community that the philosopher’s discourse can be tied to what is deemed admitted by the universal audience. It can be that the principles, considered by the philosopher
    as universally admitted only express the dominant opinion in his cultural milieu, and the knowledge proper to his age, but which everyone, in his opinion, should recognize.” Ibid., p. 58.

    “This vision of the ‘rational’ man separates reason from the other human faculties and shows a unilateral being functioning as a mechanism, deprived of humanity and insensible to the reactions of the milieu: he is the opposite of the reasonable man. The latter is a man who in his judgments and conduct is influenced by common sense.

    He is guided by the search, in all domains, for what is acceptable in his milieu and even beyond it, for what should be accepted by all. Putting himself in the place of others he does not consider himself an exception but seeks to conform to principles of action which are acceptable to everyone. He considers as unreasonable a rule of action which cannot be universalized. Starting thus, from a communal conception of reason, we end in a Kantian categorical imperative which makes the universal the criterion of morality.” Ibid., p. 118

    Note: Kantian in terms of universality, but not Kantian insofar as the principle itself is grounded in common sense.

    The Categorical Imperative, Perelman argues, is an example of what he calls “quasi-logical arguments.” That is, practical arguments which do not have the exactitude (and thus strict necessity) of formal logic, but the elements of which have a similar position vis-à-vis one another, once the minor differences that always occur in real life are excluded (what he calls a partial reduction). Kant’s rule is an example of treating equal individuals or situations the same. In his main work he describes it as part of the principle of “formal justice,” that things in like categories (all other things being equal) are to be treated in like fashion. The specific section of quasi-logical arguments in which Kant’s rule is treated he terms “Arguments of reciprocity,” noting the following:

    “Often a transposition, emphasizing the symmetry, (Put yourself in his place!) provides a basis for what is deemed to be a well-founded application of the rule of justice….

    The precepts of humanistic ethics, whether they be Judeo-Christian maxims (‘Therefore all things whatsoever ye would that men should do to you, do ye even so to them’) or the categorical imperative of Kant (‘Act only on that maxim whereby thou canst at the same time will that it should become a universal law’) require that neither the individual nor his rules of action may claim any privileged position, that, on the contrary, he is governed by a principle of reciprocity which appears rational because it is quasi-logical.” (Perelman and Olbrechts-Tyteca, The New Rhetoric, p. 222)

  17. mpboyle56


    NB: In his 1979 work, Perelman does discuss Goblot briefly.

  18. Michael Boyle,

    I’m working a broader, hopefully deeper comment, while reading some background material. I did want to say, “Philosophy of rhetoric! at last!” We almost never see this topic addressed in any site primarily concerned with philosophy.

    Rhetoric, its origins, structures, and use, has been a thorn in the side of philosophy since Socrates; but it need not be. Is there not also a wisdom of rhetoric, even if merely description of it? But of course its success beggars formal logic (of any kind) and so threatens the social dominance of formal logic models of language. But it *is* successful, frequently far more so than formal argumentation. Consequently it raises important questions concerning the very nature of language that no formal logical system can properly consider.

    I also remark that I remember I did have to read some essays or excerpts from Toumlin in my doctorate English program; but when I did post-graduate work in philosophy, nobody had heard of him. But given that most philosophers at the time had little understanding or interest in rhetoric, this is not surprising. (It should not be at all surprising that the Phenomenological tradition, which considered rhetoric an important topic of discussion, had such an impact on literary studies in the ’80s. One of Derrida’s key texts carried the subtitle “Metaphor in the Text of Philosophy”* – the very notion of which might chill the blood of most Analytics.)


    Without getting into the technicalities of Michael Boyle’s discussion (which I’m still working through myself), I note that your comment rather ignores the overlap and conflict between differing social contexts. Within a meeting of stockbrokers, one form of rhetoric is to be expected, given the shared values of those attending; but drawn out into political arguments concerning national economy, an entirely different rhetoric, derived from different values, would be necessary.


    I’ve read your link; there’s nothing wrong with a computer mapping of informal argumentation, as long as we understand it is a tool for understanding such arguments that exist. But the real power of a good rhetoric or philosophy of rhetoric is that it aids in the the composition of stronger rhetoric. (Most forget that Aristotle’s “Rhetoric” was intended as a manual for his students, to aid them in political survival without sacrificing their values.)

    * White Mythology,

  19. mpboyle56


    “Rhetoric, its origins, structures, and use, has been a thorn in the side of philosophy since Socrates; but it need not be. Is there not also a wisdom of rhetoric, even if merely description of it? But of course its success beggars formal logic (of any kind) and so threatens the social dominance of formal logic models of language. But it *is* successful, frequently far more so than formal argumentation. Consequently it raises important questions concerning the very nature of language that no formal logical system can properly consider.”

    Yes, this is precisely part of what motivated Toulmin and Perelman. Speaking of Toulmin, I think one of the best summations of what he did and why comes from the man himself, in a piece entitled “Logic and the Criticism of Arguments” (link below).

  20. mpboyle56


    This is all very interesting but I think it’s a bit too meta and reductionist to really apply to Toulmin and Perelman. My own views on explanation and understanding are basically consistent with DanK and Massimo’s views:

  21. I don’t understand the responses to my point either. Both Dan’s and Mark’s responses referred to field-dependency of justification which is something I had not questioned, or even alluded to. On the other hand neither response mentioned the distinction between demonstrating the truth (or probable truth) of something and convincing people of it, which was the entirety of my point.

    There may be something that I am missing in those responses.

  22. brodix


    I certainly agree it is meta, but isn’t meta conceptual context? Yes, it is reductionistic, but isn’t the premise of philosophy to extract some degree of order from the chaos?

    To paraphrase an old saying; Some people live to philosophize and some philosophize to live. I try to be of the later. Not always successfully. Though I’m more interested in the concepts then their entire history.

    I will take the meta as a compliment though. Usually I just ruffle feathers among the professionals.

  23. I am reading a little of the book and it is a little puzzling. For example he says

    Ever since Aristotle it has been customary, when analysing the micro-structure of arguments, to set them out in a very simple manner: they have been presented three propositions at a time, ‘minor premiss; major premiss; so conclusion’. The question now arises, whether this standard form is sufficiently elaborate or candid.

    What is he doing talking about “major and minor premisses” and “Universal premisses” when these terms were long obsolete in logic by 1958?

    He presents the D,C,W,B,Q,C scheme as superior to the “Universal to particular” form of syllogism, and it may be, but why is that a relevant thing to say in 1958? Why does he spend many pages arguing that his scheme is superior to an obsolete form of logic? It is like presenting a new theory in physics and showing why it is superior to the theory of ether.

    Actually I doubt that anything that can be stated in his DCWBQC schema could not be expressed in classical or first order logic. And there seems to be something missing in the DCWBQC schema – I will elaborate later.

  24. Hi Michael Boyle. Thanks of an insightful series of articles. I went back to review the pre-WWII part and the description of your class. It’s a kind of astounding irony that in the course of struggling with two powers that wrought incredible destruction through propaganda, we should have shut down those who tried to study and criticize it. There is the natural antithesis that it threatens the advertising industry and hence the whole commercial world, and any thorough look at propaganda is bound to offend religion – particularly the Catholic Church at that time, which in the past invented the word, and which was at the leading edge of anti-Communism. And then there is the short-sightedness of “We have to have our propaganda.” If propaganda is outlawed, only the outlaws will have propaganda, so to speak.

  25. But then I’m not at all sure that much can or should be done through anything like outlawing. OK, some restrictions on how to advertise to children. And the intelligentsia talking to itself about “critical thinking” or whatever won’t go far IMO. Integrating it into education with tools for resisting propaganda has some hope. I made a proposal once about a kind of bottom up experimentation in hopes of contributing to a movement in “Possible Approach to “Tune Out” or Neutralize Money in Politics? A Small Experiment.”.

    Present day “movement conservatism” began with conversations among a few men like Hayek and Popper, wondering how to move the world so that “never again” and a resolution to hold yearly meetings to define and expand the cause (which mistakenly saw too many things as being on the “slippery slope to totalitarianism”).

    Maybe a movement for standing on our dignity and not being constantly spoken to like children, if people come to realize that’s what’s happening — could gain some popular appeal.

  26. mpboyle56

    @ Robin Herbert:

    Two points:

    1. It is not outre to see philosophers analyzing a contemporary argument by invoking notions like major or minor premises, etc. in the course of analysis.

    2. The larger context in which what you quoted occurs is Toulmin’s contrast between the Platonic, geometrical (i.e. monotonic) notion of arguments as compared to a defeasible model of argumentation. In that much more zoomed out view of the history of philosophy, Toulmin argues that both the syllogism and modern formal logic a la Frege et. al. belongs to essentially the same category (Perelman makes the same basic point). Van Bentham’s retrospective (see footnote 3) gives some context to this. He concedes that this was the main direction in modern logic and he admires the value of Toulmin’s argumentation model. He is, however, nonetheless critical of what he sees as Toulmin breaking away from logic, partly because there were a few minority voices within logic both before and during Toulmin’s time that were trying to extend logic in the same direction, an approach (non-monotonic) that has now become respectable in recent decades.

  27. mpboyle56

    @ Robin Herbert:

    “Actually I doubt that anything that can be stated in his DCWBQC schema could not be expressed in classical or first order logic.”

    Logicians like van Bentham clearly see things differently:

    “Reasoning is an activity, functioning among many forms of information flow, and agents like us are constantly performing acts of observation, inference, belief revision, or evaluation that guide our behaviour. Moreover, crucially, we do not do this in isolation, but interactively with others: pure deduction on one’s own is an extreme case. Now modern logic just studies some products of such
    acts, such as inference forms, or static instantaneous knowledge and beliefs of agents. It does not study those acts themselves, even though only the latter create the products, and make sense of them.” (7)

  28. Robin Herbert,

    In early days of the 20th century, Bertrand Russell developed his theory of reference, using as a primary example the sentence “the present King of France is bald,” which, he held, could not be meaningless, although there was no such entity.

    It’s just as well he didn’t cross the Channel and engage in French politics, where the (then quite active) Royalist underground could have told him that one King of France, the Bourbon, was indeed going bald (although the Orleans claimant had quite a shock of hair). The Royalists would not have recognized the corollary to his argument, “there is no present King of France” as statement of fact, but as a political assertion – a rhetorical speech act.

    Fortunately for Russell, the Royalists achieved no political power (although they have occasionally contributed to right-wing social movements).

    Let us consider the assertion that “Obama is not really the President of the United States.” “Therefore” (actionable conclusion), “he should be removed from office.”

    This is derived from two basic assumptions.

    1. Obama cannot prove he was born in the US; legally this disqualifies him from office.
    2. Obama is a black Muslim, and America is a predominantly white Christian nation.

    If the first clause of the first assumption is correct, then the assertion of the second clause happens to be correct, according to the Constitution.

    The second assumption is more complex, because it derives from a heavily shaded reading of American history, that basically denies that the Constitution has authority over the ‘will of the Founders’ expressed through historical development. In other words, while the Constitution is effectively invalidated by this assumption, it is also assumed that the Founders simply could not have imagined a black Muslim president, and would have written a different Constitution otherwise. (It also assumes facts not in evidence, derived from Obama’s family background and name.)

    The claim is not unreasonable, even though some of the claim’s justification lacks warrant. And it grounds the rhetoric of the current front-runner of the Republican candidates for the presidency, David Trump.

    It is not good enough, to understand what is going on here, to simply call Trump and his followers irrationally ‘crazy;’ as already noted, there is a certain chain of reasoning in their thinking. One really has to argue that defacto legitimacy re-enforces known dejure legitimacy, thus cancelling out this argument altogether: Obama has fulfilled the responsibilities of the office of president for now 7 years, and the only body that could delegitimate him, the US Supreme Court, has found no cause for doing so. Thus, while he may not be the president some people would like, he is, ipso facto, the legitimate President of the United States.

    There’s not any way to account for any of this in formal logic, certainly not in First Order logic. (If you think so, show me.)

    Finally: the notion that syllogistic logic was made “obsolete” by innovations in symbolic logic is simply wrong. They merely limited its uses.

  29. Hi ej and Michael

    Note I didn’t say that logic could do anything. I said that I doubt that Toulmin’s DWBQRC can do anything that, say, propositional calculus can’t.

    I don’t see how the Van Bentham quote contradicts that. And ej, if you can show me the DWBQRC analysis of the birther claim then I can show you the propositional calculus version.

  30. mpboyle56

    @ Robin Herbert:

    If modern logic has limitations, then so do, a fortiori, other, older logic systems. That was part of the whole point of having to develop non-monotonic logics, after all.

  31. Incidentally, it would not have posed any problem at all for Russell if there had, in fact, been a King of France at the time he was devising his theory of definite descriptions. If it did then he would have only been recreating the problem he was attempting to address in reverse, and Russell was too smart for that.

    Incidentally I have seen a formalisation of Anselm’s original Ontological argument in S5 and using Russell’s theory of definite descriptions to justify the final step. Russell would have been spinning in his grave. But it pretty much refutes the idea that logic can’t handle field dependence and communities of minds with their own standards of evidence.

    And, yes, the kind of Aristotlean syllogisms that Toulmin is talking about are certainly obsolete. If there are still philosophers couching arguments in terms of major and minor premisses I would like to see it.

    Of course the form can still be used if one wants, in the situations in which it works, but to speak of it in 1958 as though it were the standard against which any new schema should be judged, is absurd. Toulmin even identifies some of the reasons that they are no longer used – the existential implication for example – but to read the book you would have thought that Toulmin had just discovered this.

  32. Hi Michael,

    If modern logic has limitations, then so do, a fortiori, other, older logic systems. That was part of the whole point of having to develop non-monotonic logics, after all.

    Again, I said that I doubt that Toulmin’s DWBQRC schema can do anything that, say, propositional logic can’t.

    If one was to develop a new logic to address the limitations of older logic systems it might be reasonable to expect that they can do something that the older logic system can’t.

    I am yet to see what these might be.

    I haven’t finished the book yet, but Toulmin has spent an inordinate time arguing the superiority of his schema over Aristotlean universal to particular syllogisms, rather than over the accepted logical forms of his time.

  33. mpboyle56


    You are missing the key distinction Toulmin (and Perelman) are making. As I mentioned earlier, the syllogism is a paradigm case of the geometrical model followed by deductive logic- the conclusion following necessarily from antecedent information. Don’t get hung up on syllogisms per se- that’s not the general point, as is made very clear from Toulmin’s ouvre. The point is that they are a paradigm of deduction tout court. Ordinary arguments do not follow such a structure, which is why Toulmin and Perelman developed their ideas and saw Aristotle’s Topics and Rhetoric as a precursor. Furthermore, possibility in logic is not the same as possibility in ordinary argumentation, which varies depending on what we’re talking about and in what context and the subject or field. Logical possibility is formal, possibility in practical argumentation is not. One runs on logical entailment, the other on judgment (this is why casuistry was so important to Toulmin). The development of non-monotonic logics tries to get around this, but has substantial difficulty precisely because of trying to capture the heterogeneity of practical reasoning within the necessary homogeneity of a formal system, capturing the inherent and ineliminable particularity of practical argumentation within the universal formality of a system of logic:

    “There is a potential tension between (i) and (ii) [material adequacy & formal properties]: the desire to capture a broad range of intuitions can lead to ad hoc solutions that can sometimes undermine the desirable formal properties of the framework. In general, the development of NMLs and related formalisms has been driven, since its inception, by consideration (i) and has relied on a rich and well-chosen array of examples. Of course, there is some question as to whether any single framework can aspire to be universal in this respect.” SEP, s.v. Non-Monotonic Logic, 5. Conclusion.

    In terms of analyzing arguments (especially those of others) and unpacking them in terms of what follows from what and even using terms like major or minor premiss, that, as I said, is not outre. And no, it is not always strictly in the form of a categorical syllogism (if you want to take that as a Lilliputian victory and uncharitably ignore the context of Toulmin’s argument, feel free). Quick examples:

    Rule-following and Meaning, eds. Alexander Miller and Crispin Wright (Routledge, 2002), p. 67:

    “We can summarize Wright’s reading by saying that he takes Wittgenstein to propound a modus tollens argument with the conditional as major premise. Thus: the idea of knowledge of idiolectic meaning is an illusion; therefore possession of a concept cannot be correctly conceived as grasp of a (ratification-independent) pattern. The basis of this argument is, as Wright points out, ‘the fundamental antirealist thesis that we have understanding only of concepts of which we can distinctively manifest our understanding’. Wright would ground both premises of the modus tollens argument on anti-realism. The justification for the minor premise is that the picture of an idiolectic rule makes no room for a distinction between actually conforming and merely having the impression that one is conforming. In Wright’s reading the thought here is an anti-realist one: that in an idiolectic context one could not distinctively manifest – not even with a manifestation to oneself – a difference in one’s understanding of ‘I am actually conforming” and “I have the impression of conforming’.What underlies the major premise – the
    conditional – is the anti-realist conception of what it is to manifest understanding to others.”

    Jerry Fodor, Concepts: Where Cognitive Science Went Wrong (Oxford, 1998), p. 149.

    “Now, it’s true, of course, that Tuesdays are mind-dependent in at least the following pretty straightforward sense: whether today is Tuesday depends on what conventions people adhere to; and that people adhere to the conventions that they do, or to any conventions at all, depends on their having minds. So: no minds, no Tuesdays. But it does not follow that there are no Tuesdays; the minor premiss is missing. Nor does it follow that there is no fact of the matter about whether today is Tuesday (or about whether
    it is true that today is Tuesday). Nor does it follow that Tuesdays aren’t real. Nor does it follow that ‘Tuesday’ doesn’t really refer to Tuesday. As for whether it follows that Tuesdays aren’t “ ‘externally’” real, or that ‘Tuesday’ doesn’t refer to an “ ‘external’” reality, that depends a lot on what “‘external’” means. Search me. I would have thought that minds don’t have outsides for much the same sorts of reasons that they don’t have insides. If that’s right, then the question doesn’t arise.”

  34. […] comment to a discussion ( ) on the philosophy of rhetoric as developed independently by Stephen Toulmin and Chaim Perelman, a […]

  35. Robin Herbert,

    “If there are still philosophers couching arguments in terms of major and minor premisses I would like to see it.”

    We’re not just talking about professional philosophers. I’m sorry, the syllogism, and its rhetorical mirror, the enthymeme, are still alive and kicking in the world of politics, law, advertising, common discussions about film, music and where to eat for dinner. (“Shall we eat at Wendy’s?’ – ‘All fast food chains are alike; no thanks!’) They are obviously not the only forms of argument used in common speech, but they have uses.

    You seem to have totally misunderstood the field of interest for philosophy of rhetoric. It’s not about what academics work with, but about what anybody has to work with in daily life. And no, formal logic cannot encompass that. (Of course Toulmin and Perelman appear to have grasped that even different scholarly fields engage different argumentation styles and differing rhetorics; but my own concern is how we take this out into the fields beyond the Academy.)

    Even before Toulmin and Perelman, this was demonstrated by Wittgenstein and Austin. Please show me the logical calculus for ‘Hey, how ya doin’!’ But I can give you a rhetorical explanation of the social codes necessitating greetings such as these.

    When reading up on the Toulmin method, I do see opportunities for argument analysis of common speech along the Toulmin lines. I don’t see anywhere an opportunity for formal logic analysis. We just don’t talk in formal logic among our friends, or politically, or at work… I mean, once one sees how utterly limited formal logic is in terms of common usage, one grasps desperately at any thinking of language ‘outside the box’ that one can use to address the words that people actually use.

    Your demand for me to perform Toulmin analysis here is misplaced; first, because, in this present discussion, the ‘burden of proof’ is yours, since Boyle, Toulmin, and Perelman have already made their cases. You need now to show that they’re wrong.

    And I have admitted I am not comfortable enough with the Toulmin method to use it for analysis, as I am just now re-discovering it through this article.

    But I was trained in rhetoric and semiotics, so I do have rhetorical analytic tools I can deploy, concerning the example for consideration I gave above. I’ve written such an analysis (in non-technical language) of the example I gave in previous comment. However, it runs over a thousand words, much too long to post comfortably here (thus risking distraction from Michael Boyle’s excellent article). So I posted it on my own blog; here’s the link: (it opens with some material from my previous comment, so have patience).

  36. Robin:

    Toulmin is trying to devise a logic that can deal with the sorts of arguments that are commonly made in ordinary language and in various “technical” forms of speech that are tied to specific disciplines like medicine, law, and others.

    These are arguments where conclusions don’t follow necessarily, if their premises are true, and in which expressions like “most”, “a lot”, “a few” and the like cannot be captured by standard quantifiers. As for modality, “possibly” and “necessarily” do not, in many of their ordinary language uses, have the same senses of logical possibility and necessity that one would require in order for the operators of modal logic to be apropos.

  37. brodix

    Michael, Daniel,

    Aren’t you both missing the underlaying motivation, to explain why rhetoric is so effective, without necessarily being logical? Linearity, versus non linearity. Light versus heat. So trying to frame it in strictly logical terms only generates word clouds of conceptual heat, but not much clarity.

  38. brodix

    In the sense that after the war, this effort was to understand why rhetoric was so effective, even if the logic was flawed. When the function is to generate heat, thus get everyone stirred up and joining your army, even if the goal is only to build a bigger army than the other guy, it very much is a non-linear process of just running around and pushing as many buttons, pulling as many levers, popping as many bubbles etc, to build up that energy.

    Your underlaying assumption here is that there must be some underlaying logic, when it really is just this surface. Logic is linear. It is the signal extracted from that noise. There is no pre-existing linearity. The narrative is just what is channeled through the narrator.

    Plants don’t have a central nervous system to process linear logic because they don’t need one. There is no navigation function and that is what narrative arises from. People need narrative because the wheels start coming off the train otherwise and you dissolve back into the background. Yet it is that expansion/accumulation of energy and its consolidation that creates the effect of time, the sequence of events. Your heart beat.

  39. mpboyle56


    For Toulmin’s account of motivation re: the Platonic vs. Aristotelian conceptions of what counts as good reasoning and why, see the link to Toulmin’s paper above.

  40. brodix


    Thank you for the reading. Unfortunately my time was very limited today.

    I would say I’m a bit of an Aristotelian, in seeing everything extant as being subjective and relative to all else, holistically.

    My issue with Platonism is that ideals are distillations. There is no form in the void, so no perfect form either, in any meta sense.
    For instance, a dimensionless point, as an ideal of location, would be no more real than a dimensionless apple, as, mathematically, anything multiplied by zero is zero. By getting rid of all the messy dimensionality, they cancel it out.
    A circle/sphere is an efficient relationship of area to surface, yet it is still descriptive and so you need that relationship between area and surface for it to exist.
    1+1 always equals two, but + is a verb. The action has to be completed, for it to be a set of 2.

    I am one of those who doesn’t go for the whole big bang theory and rather than seeing time as primal, like Smolin, I see space as primal. If you remove all physical properties from it, it would still have the non-physical attributes of infinity and equilibrium.
    Equilibrium is implicit in clocks slowing in a moving frame, given the speed of light is a vacuum is constant, as the frame with the fastest clock would be closest to the equilibrium of this vacuum. While there would be no way to prove which is the absolute fastest, the rate of increase measured between frames would diminish, as increasingly stable frames are compared, implying a state of equilibrium to the vacuum.

    Also, using the premise of spacetime to explain redshift completely overlooks the fact that for General Relativity to apply, the speed of light would have to increase, as space expands, in order to remain constant, but that would negate using it to explain redshift, since the assumption is this is due to light taking longer to cross this space. We are to assume there is one dimension of space, based on the redshift of intergalactic light and another to compare it to, based on the stable speed of the very same light!

    Mathematically, what expands between galaxies is balanced by what contracts into them, which are radiation and mass/gravity, so I see it as an overall cosmic convection cycle, of mass/form pushing in and radiation/energy pushing out.

    Now I don’t mean to go off on a tangent, or to start another debate, but simply to argue that space is the primordial absolute. Basically all you need is the vacuum and a little instability, i.e., vacuum fluctuation and everything would arise from it. Starting with temperature and time, as effects of frequency and amplitude. Radiation and mass would emerge as this instability goes through increasing cycles of expansion and contraction.

    So essentially it would be a dichotomy of energy and form. Energy manifesting form, even if it is as basic as frequency and amplitude. While form defines energy. Energy pushing out and form pushing in.

    A useful argument for this dichotomy is that over billions of years, we as living beings have evolved a central nervous system to process form and the digestive, respiratory and circulatory systems to process energy, with all the subconscious relations between them. As well as a mental preference for form over dynamics. Thus our sense of time, as prior forms fade, while new ones emerge.

    Society then would be a dichotomy of social energy pushing out and civil and cultural form pushing in. Too much social energy overwhelming form is anarchy, while to much form pressing in is totalitarianism.

    I’ll leave it at that, as I find I mostly just aggravate people and so this is a thumbnail sketch of how I make sense of reality.

  41. My focus for the last couple of days has been elsewhere but I would like to return (at least briefly) to this discussion. I had been raising some questions about Perelman. Let me say a little more in response to Michael’s extended response to me.

    I still have problems with Perelman. For one thing, there seems to be a degree of equivocation in his writing concerning the meaning of the words ‘universal’ and ‘universalize’. To the extent that a perspective is time-bound or culture-bound, it is not universal even if it purports to be. Perelman acknowledges this explicitly at times, but then seems to revert to talking about universalizing in more naive terms at other times.

    In the essay I alluded to above (‘Justice and justification’) he makes it very clear that his main goal is to justify fundamental (presumably universal) values. He exalts the philosopher much as Shelley exalted poets as “the unacknowledged legislators of the world”. This goes very much against the grain with me. It is also a position which would never win wide support, especially today when respect for philosophy and philosophers is at such a low ebb. Perelman writes:

    “Taking the judge, arbiter, and legislator as models, how should we define the role of the philosopher, who has to formulate just laws and judge in an impartial fashion, not for a given society or a limited social or professional group, but for the whole of humanity? What distinguishes him as such is that he must look for criteria and principles and formulate values and norms capable of winning the adherence of all reasonable men.”

    It seems in fact that Perelman claims more for moral philosophy than Kant does:

    “For Kant, a pure practical law, established a priori, can only be formal – that is, its form alone makes it appropriate for universal legislation. My views go beyond that, for I do not believe that a philosopher should limit himself to the formulation of a purely formal law comparable to the rule of justice.”

    He concedes that “the propositions the philosopher might present to all men cannot prevail with a necessity and an evidence which would put them beyond the test of any challenge,” and also that philosophers disagree amongst themselves about the criteria and content or the values they evoke. But he seems to assume we are still back in the age of philosophical idealism when he talks about them invoking “universal values like truth, goodness, justice, and reality as opposed to appearance.”

    Do the disagreements (between themselves) of philosophers, he asks, “mean that their efforts, and the conceptual constructs which result from them, are nothing but illusions, or that individual myths have merely replaced traditional and collective ones?”

    Not at all! This is what we might think about metaphysical assertions “if we had to assimilate them to empirically verifiable scientific theories. But assertions which represent the systematic formulation of an ideal cannot be judged the way we judge factual judgments. Their role is not to conform to experience, but to furnish criteria for evaluating and judging experience and, if necessary, for disqualifying certain aspects of it. This is exactly what a philosopher does who opposes reality to appearance through the establishment of a hierarchy of values among the diverse manifestations of reality.”

    This is heady stuff, good old fashioned metaphysics! Note the idea of the philosopher opposing “reality to appearance through the establishment of a hierarchy of values…”

    Perelman was, of course, reacting against the tradition of logical empiricism, but he seems to be doing so by reverting to older traditions of thought, including a tradition of philosophical idealism which has, I think, been largely discredited in most secular contexts.

  42. mpboyle56


    Many thanks for your considered response. My answer is a longish one, so let me ask for your indulgence once again.

    I have now had a chance to look at the essay of Perelman’s to which you refer and I must say I respectfully disagree with your interpretation, viz:

    “To the extent that a perspective is time-bound or culture-bound, it is not universal even if it purports to be. Perelman acknowledges this explicitly at times, but then seems to revert to talking about universalizing in more naive terms at other times.”


    Perelman is not an idealist in the old-fashioned way that you mean. His constant reiteration of moral arguments as defeasible and contingent demonstrates this clearly, I think. The “ideal” of which he speaks is conceptual, not metaphysical, akin to the notion of ideal triangularity in mathematics, which (on an Aristotelian view) does not require that I believe in a Platonic realm where such triangularity actually resides.

    This however, seems to me to not be the most important observation which he makes in the essay, because there is a much more profound point on the grounds of which he argues for both the importance and validity of practical argumentation re: values, namely the ineliminability of values even for the positivist, a contention argued for both by Murdoch and the contemporary American pragmatist Hilary Putnam. There is not demonstration on the one hand and justification on the other, although not everything (shades of Wittgenstein the Thomas Reid, etc) is justified:

    “For centuries logicians have been able to neglect the problem of the justification of one’s choice of axioms, by considering the latter either as self-evident or as arbitrary. In the first case, since we must bow to the evidence, we have no choice and therefore no need to justify our acceptance. In the second case, since all choices are considered equally arbitrary, it is impossible to justify any one by showing it to be preferable to any other. When we reject both of these extremes, so reminiscent of realism and nominalism, when we admit that a choice of axioms is possible and that it is not entirely arbitrary, then the justification of choice ceases being a negligible problem.

    If we transpose the same reasoning to the first principles of philosophy, which are considered to be neither self-evident nor arbitrary, the very center of philosophical thinking becomes transferred from the realm of theory to that of practice; we are heading toward the justification of our philosophical choices and decisions. But a philosophical justification must not refer to the interests and passions of a particular group: if it is not presented as being universally valid, it does not constitute an admissible philosophical justification. A philosophical justification must be rational, or at least reasoned.

    It would never occur to us to want to justify every one of our actions or beliefs. Methodical doubt as practiced by Descartes is conceivable only if a self-evident, indubitable intuition allows us to eliminate it. The problem of justification arises only in the practical realm, when we have to justify a decision, an action, or a choice which has no incontrovertible evidence to guarantee its validity. In this perspective, a desire to justify everything appears completely senseless, for it is unrealizable and would only lead to infinite regression. The enterprise of justification has meaning only if the acts one is seeking to justify are open to criticism; that is, if they possess some fault that makes them inferior to other acts which are uncriticized and which therefore need no justification.” (5, 6)

    Furthermore, he explicitly rejects the notion of universal vs. individual used by Kant:

    “In opposing maxims to laws, Kant tells us that the maxim is subjective because the subject considers the condition which determines his will to be valid only for his will. The law, in contrast, is objective if the condition is recognized to be valid for the will of all reasonable men. This dichotomy, with its opposition between the individual and the universal, seems to me to be contradictory to the facts and chimerical. As soon as we formulate principles of action, whatever they may be, we eliminate something of the arbitrary from our conduct. Our behavior, being ruled, is no longer entirely dependent on our subjective whims; our rule might even become the principle of action of a community, if its members were inclined to accept it. On the other hand, none of us is the judge in the last instance of principles considered to be objectively valid; that is, valid for the will of any reasonable man. No one of us can declare, a priori, as a result of his own conviction, that any man who does not consider such principles to be objectively valid is not a reasonable man.” (15)

    Lastly, immediately prior to the foregoing section, he directly analogizes the philosopher’s search for the universal to the task of a common law judge:

    “If the philosopher succeeds in finding certain criteria and principles, certain values and norms which to his knowledge are not rejected by any reasonable being, he will gladly make these the basis for a universal law. Such principles and values possess the advantage of not having to be justified-not because they are self-evident, but simply because they are not contested. Privileged principles of this sort will be most often ambiguous or equivocal and hence liable to different interpretations. Then the philosopher’s role will be to clarify and specify them, by discarding those formulations and interpretations which in his view could not be defended before a universal audience. He will act according to the same considerations in working out the techniques of proof and interpretation which are indispensable for the establishment of facts and the application of laws. In his effort to formulate just rules, he will seek, like the common law judge, precedents to guide his judgment…. (14)

  43. Hi Mike, thanks for the reply. I’ve been following your other replies (and at least one link) to try to piece to together a more complete picture.

    Thinking about my initial concern I realised it was actually three, two of which you pretty much identified and addressed. The link you gave was interesting and if I am understanding it properly may also go to address one of Robin’s original concerns (“distinction between attempts to convince and demonstrating the truth or likelihood of a claim”.

    To repeat my concern (in a bit different lingo) I came away from your essay wondering if the idea was that all positions/arguments were defeasible and so solved/addressed as easily and accurately by rhetoric (convincing others, particularly within a field) as formal analytical methods. That is as if a factual relativism existed (and by that I don’t mean simple field-dependence).

    From your explanations and links the case seems to be (if I understood them properly) that in the spaces where formal analytical methods do not apply or do not present singular solutions (by removing alternatives as invalid) or where experience from multiple fields may be applicable, informal (substantive) methods are legitimate and useful. This includes rhetoric. And it happens that there are a lot of such cases.

    To a large degree this is acceptable to me. I might note that my own philosophy program dedicated a very large portion of its logic course to informal logic and application to specified topics (perhaps as it was close to Chicago where Toulmin mentioned his idea’s acceptance?) .

    Interestingly, I’d disagree with Kock’s implication that moral relativism is problematic and somehow overcome by Toulmin’s rhetoric (as interpreted by Ras which I really liked). Rather (to my mind) moral relativism simply refers to where an “incommensurability of warrants” has been identified as the existing state of ethical choice (by philosophy), and rhetoric becomes the legitimate working methodology. Not in the cheap, propagandizing sense of rhetoric but the one advocated by Toulmin/Ras/Kock. (Side note, Christian Kock is from the University of Copenhagen not Amsterdam)

    I am more concerned with factual relativism, where just about everything is up for grabs despite experience and logical analysis, as long as someone can be convinced otherwise. I agree people can live “as if” many different interpretations of evidence are true to the world, but that doesn’t make them equally accurate or useful or indicative they are all right.

    This leads to my last problem which was not addressed, what of personal or external bias? One of the links seems to have Toulmin arguing the rationality of business people. That was a dream whose time was officially over when Greenspan threw in the towel during the financial crisis. It is possible for people to become “unreasonable” due to ideological or psychological or sometimes even biological biases. We saw this at work in the field of business throughout the economic crisis (more with the so-called experts working in industry and government than in academics). The strength of formal logic or evidentiary analysis (science) is that it can be used to cut through personal biases like ideology and propagandized forms of rhetoric.

    I am wary of championing rhetoric as something beyond a supplement to, or that it should somehow be allowed to come before, more strict forms of analysis (for important decisions).

    As an added point from the discussion, I am a bit uncomfortable with the use of “universals” to describe anything, particularly truths and audiences. That said I tend to agree with the ideas (if not the language/terminology) of Perelman in the quotes you gave addressing universals, particularly in opposition to Kant.

  44. mpboyle56


    “The strength of formal logic or evidentiary analysis (science) is that it can be used to cut through personal biases like ideology and propagandized forms of rhetoric.”

    Toulmin readily concedes (e.g., in his textbook) that where greater precision is possible (within a reasonable time frame) with things like mathematics in terms of business decisions, that these tools can and should be used. He also contrasts the condition of being “needleesly and willfully uninformed” with the notion of a reasonable decision based on the timely assembling of all data (including especially all factual data). What data is relevant and what constitutes timely are still however, at the end of the day, non-deductive judgments. Even in matters of aesthetics, Toulmin notes, arguments can be clearly wrong, particularly if one’s judgments are based on incorrect factual data (e.g., “[i]f…you do not understand that many of Rubens’ large group paintings have allegorical or symbolic themes, the interpretations you offer of those paintings may end up being merely silly.”).