ISSA Proceedings 1998 – The Concept Of Resolving Differences Of Opinion And Its Practical Implications In Planning Theory
There is an anecdote of the famous philosopher G.E. Moore, who was once preparing a paper for a seminar and, being unsatisfied for the closing of his argument, complained about it to his wife over the breakfast table. “Don’t worry, darling, I’m sure they will like it,” said his wife. To which he responded boldly: “If they like it, they are wrong.”
This anecdote illustrates the once clear distinction between being right and succeeding in persuading your audience in thinking so. This attitude, self-evident at least in the analytic tradition in epistemology and philosophy of science, is perhaps in danger of fading away in the midst of rhetorical, discourse analytic, social constructionist, and even some argumentation theoretic studies. Should we miss it, or even defend it? Could be assume that a ’real’ solution can be defined, not only in science, philosophy, or formal logic, but also in practical contexts like moral and political debate and planning of the physical environment? This is a question I shall be addressing in this paper, although, like Moore, I am not at all satisfied with the closing of my argument. I would like to say much more about what a solution is, but I shall be saying much more about what it is not. The concept of solution is not only at the heart of argumentation theory and, as might be added, one of its unresolved problems, but it is also the concept through which the applicability of argumentation theory in practical reasoning is measured. It is not uncommon that argumentation theory is in practical contexts dismissed as an idealized, absolutist theory that has very little to offer to practitioners working in an “unclean” environment of power relations, hidden motives and conflicting interests. In this paper I shall discuss this issue by first analysing some classical texts and their ways of dealing with the subject and, secondly, demonstrate how the interpretation of this concept will appear essential in the practical context of spatial or physical land-use planning.
In recent decades, both planning theorists and practicioners have started discussing the so-called communicative or argumentative turn in planning. This is taken to mean a change in both the rationality conception of planning and in the actual planning practices: away from instrumental rationality and technical expertise that were earlier supposed to be able to define the way that common activities in space can be organized, and towards a communicative approach that will activate people as “stakeholders” to come together to define their priorities and common interests (Healey 1997, Forester 1989, Sager 1994, Fischer and Forester 1993). This entails that the communicative situation and process will get a more central role. If local participation in planning is supposed to provide not only local information and expressions of interests to be interpreted and evaluated by professionals and politicians, but really to provide a way of “making sense together”, then the quality of argumentation in the planning process will become central.
Defined in this way, communicative planning theory is a normative-practical theory (Healey 1997, 68), and it would thus seem to fit into the tradition in argumentation theory that will try to combine empirical and normative elements in communication, such as the pragma-dialectical theory (van Eemeren and Grootendorst 1992). However, spatial or land-use planning is also a communicative practice that differs from the more paradigm cases referred to in argumentation theory, such as jurisprudence or science. It is an instance of political or policy discourse and, consequently, strongly dominated by rhetorical communication. But this is not by itself an obstacle. Supposing that the concept of resolving differences of opinion (instead of merely settling the disputes or negotiating between the parties with conflicting interests) is the dividing line between argumentation theory and rhetorics, then the communicative theory of planning as a normative theory should benefit from the theory of sound, non-fallacious argumentation. This would make it possible to evaluate and criticize argumentation in planning, and even to provide the practicing planner with a toolbox for making better arguments (Lapintie 1998).
However, since communicative planning theory is also a practical theory, this will not be sufficient. Suppose that, in spite of all efforts to avoid fallacies and to take care of relevance in communication, no common solution is found, in the sense that the parties are not ready to accept each other’s arguments, or withdraw from their conflicting standpoints? This is usually resolved by lifting the problem from the public meeting to the official political level, or sometimes by letting the expert do his job alone. But this would mean the shipwreck of communicative planning. Another possibility is that a common solution is found, but it is not in every respect a good solution, because the “best” argument has not won, or it has not even appeared in the discussion. I refer to situations when e.g. severe environmantal risks are created due to an insufficient understanding of the environmental impacts of development. Similarly, the least advantageous groups of the community (children and adolescents, the elderly, the unemployed, the meantally ill, etc.) may have difficulties in getting their voices heard, since they do not or cannot particiapate in the planning process. And even if they do, they have very different cultural capacities to produce sound arguments, and they are perhaps listenend but not taken seriously.
Traditionally, these difficulties have been dealt with through professionalism: the professional planner and policy maker are supposed to take into account also the interests of those who are not present or able to defend themselves. They are also supposed to carry out the relevant investigations in order to assess the environmental impacts, health hazards, etc. This is not always the case, but in any case it is the ideal of professionalism in planning, sometimes called rational or scientific planning. But how is this related to the idea of the communicative turn, according to which rationalist expertise is to be discredited, and local participation and consensus-formation should take over? Are we not facing the classical dilemma of Aristotelian rhetorics: “Even if we had the most accurate scientific investigation in use, it would be very difficult to get some of our audience convinced by arguing only on that basis.” (Aristotle, Rhet. I 1, 1355a25) The communicative planning practice may thus be said to solve some problems of traditional planning (authoritarian governance, closed an insensitive expertise, the predominance of certain private interests, etc.) at the price of creating new ones, which had already been solved through professionalism.
The actual situation is much more compex, however. One of the reasons for the growing interest in direct participation in planning has to do with the general level of education, as well as the multiplicity of disciplines relevant to planning. The communicative process in planning is no longer (if it ever was) one between a few experts (the planner, the architect, the engineer) and a number of lay persons, the former explaining and the latter protesting. Instead, the planner is often dealing with a number of issues (such as ecology, ethics, economy, social life) of which he does not have any specific expertise. He may or may not be backed by some special experts, but his role is in any case rather one of combining and interpreting, and possibly negotiating and communicating, than providing some kind of universal super-expertise. On the other hand, the ’stakeholders’ may today hold expertise in many fields far superior to that of the planner.
Thus we end up in a combination of different types of expertise, local knowledge and ignorance, and different levels of professionalism and ethical concerns. What is the role of argumentation in this context? In order to address this dilemma, we have to consider the possibilities of argumentation theory to grasp such an interdisciplinary and public-private field of argumentation.
2. Logic, Argumentation and Rhetoric in Perelman and Toulmin
There are important features combining the new rhetoric by Perelman and the argumentation theory by Stephen Toulmin, and it is evident that these features have also had a wide influence, not only in argumentation theory but also in the many applications of the argumentative or rhetorical turn in social sciences and social practices. Some of these features are positive, of course, but in what follows I shall discuss two of the features that have proved to be problematic from the philosophical and theoretical point of view, and consequently also in practical applications.
The first is their relation to formal logic: both writers take care to dissociate their idea of argumentation from formal, analytic reasoning, and they both see Descartes and the rationalist tradition as their main opponent. They do so in different ways, however: whereas Perelman offers a caricature description of what logic is, Toulmin suggests a “revolution” in logic, comprising a dethrowning of analytic reasoning in favour of a more tolerant applied, empirically based logic.
Secondly, neither of the modern classics respects the classical distinction between dialectic and rhetoric, or the corresponding modern distinction between argumentation and rhetoric. In Perelman and Olbrecht-Tyteca (1971), the terms dialectic, rhetoric and argumentation are simply used as synonyms, or nearly equivalent. Toulmin does not mention the term rhetoric in The Uses of Argument (1995), nor does he consider the classical roots of his theory. What he clearly is after is, however, a theory of dialectic, but since he is unable to make explicit the distinction between his “practical logic” and rhetoric, the two tend to get mixed.
We can say, today, that the attempt to dethrown logic by Perelman and Toulmin was, although historically undestandable, essentially unnecessary. The Cartesian legacy – in spite of Descartes’ original intentions, was never so strong as both Toulmin and Perelman led us to believe – at least no more in the 1950’s, when they were both writing. What they almost totally ignored was the other side of Descartes, his reflections on uncertainty and the methodological doubt, which have dominated modern epistemology ever since. As a result, it is the awareness of the fallibility of scientific knowledge – and the inability of pure logic and mathematics to provide information of the empirical world – which we can find in all modern theories of epistemology and the philosophy of science. On the other hand, the development of modern formal logic has made it an invaluable and inescapable tool in all argumentation – though by no means a sufficient one in the case of non-analytic reasoning. But who ever said in the 20th Century that it would be sufficient?
Secondly, we may contend that the classical distinction between dialectic and rhetoric, in spite of Perelman’s attempt to dissolve them, is still important, and, if we want to produce a comprehensive theory of argumentation, inevitable. Consequently I would suggest that the term argumentation should be reserved only to the modern descendants of dialectics. This would be consistent with the implicit meaning given to the term in both mainstream philosophy and scientific reasoning, and also the modern developments in argumentation theory, for instance the pragma-dialectical approach by van Eemeren and Grootendorst.
Although both Perelman and Toulmin share a common distaste of analytic reasoning and Descartes, they handle it in different ways. Perelman and Olbrechts-Tyteca give a rather short and rough picture of the logician, who “is free to elaborate as he pleases the artificial language of the system he is building, free to fix the symbols and combinations of symbols that may be used. It is for him to decide which are the axioms, that is, the expressions considered without proof as valid in his system, and to say which are the rules of transformation he introduces which will make it possible to deduce, from the valid expressions, other expressions of equal validity in the system.” (Perelman & Olbrects-Tyteca 1971:13)
In reality, of course, choosing axioms and rules of inference is by no means free, and the business of formal logic is not only to deduce theorems from any set of axioms, but to develop different logical systems in order to analyse the validity conditions of different types of logical inference. Formal logic is formal, of course, but the different systems of formal logic can be used, at least in philosophy, in analysing the logical structure of argumentation that is usually expressed in natural language.
But this crude vision of logic is given in The New Rhetoric in order to make the distinction between demonstration and argumentation. Argumentation, according to Perelman and Olbrechts-Tyteca, aims at gaining the adherence of minds, and it is thus essentially dependent on the audience. While logical validity is totally dependent on ther form of the statements (the premisses and the conclusion), the success of rhetoric or argumentation is totally dependent on how the defender of the claim succeeds in persuading his interlocutors.
The writers don’t claim that logical inference could not be used in argumentation. In fact, one of the schemes that they use in The New Rhetoric and The Realm of Rhetoric is the so-called quasi-logical argument, which looks like a logical inference, although it does not comprise a formally valid deduction. These arguments would need a conscious process of reduction in order to make them formally valid, but still they derive their persuasive strength from this likeness to well-established modes of reasoning (Perelman & Olbrechts-Tyteca 1971, 193).
Given these definitions, does this dichotomy make sense? Can there be formally valid logical argumets at all? Perelman and Olbrechts-Tyteca seems to think not, since “the very nature of deliberation and argumentation is opposed to necessity and self-evidence, since no one deliberates where the solution is necessary or argues against what is self-evident.”(Ibid, 1) But this seems strange, since mathematical proofs are logically valid and necessary, and thus conceptually self-evident, but they are not easily seen as such, and mathematicians certainly deliberate about the validity of difficult theorems. Similarly, philosophers often argue against theses which they claim to be inconsistent, but which are not necessarily seen as such. The a-temporal nature of demonstration that Perelman often refers to is far from reality, considering the difficulty of logical and mathematical reasoning.
However, this is a minor difficulty in comparison with another implication of this demonstration/argumentation dichotomy. Perelman insists that argumentation is not only audience-dependent but also non-compulsive (Ibid., 1), so that the audience is in fact free to accept or reject any of the arguments presented to it. Effectiveness, thus, becomers the primary criterion of good argumentation. How, then, will it be possible to define rationality or reasonability within argumentation, which is the expressed objective of Perelman, namely to “break with a concept of reason and reasoning due to Descartes”?
Does this mean that truth and reasonability also become audience-dependent, in the sense that each audience has its own truth? In order to avoid this kind of extreme cognitive relativism, Perelman was forced to introduce his famous concept of “universal audience”. The universal audience is “anybody who is able to understand us, who is able to follow our argument. (…) The universal audience implies, in short, a group of reasonable human beings who are capable of responding to a logical discourse.”(1982b:8) He seems to imply that the universal audience will become convinced only by true statements (1971:31-32, 1992a:32). However, the universal audience is not, for him, a universal idealization, but only a construct made by the arguer: “Each individual, each culture, has thus its own conception of the universal audience.” (1971:33).
Not surprisingly, many sociologists find this notion too philosophical. For instance, Ricca Edmondson argues that “history gives no grounds for assuming that any all-embracing conglomerate of actual audiences would ever have personal and political preconceptions which balanced each other into a transcendent accuracy” (Edmondson 1984:158). This criticism is, however, somewhat beside the point, since nothing will prevent the arguer of constructing such a conglomerate in his or her mind. But Edmondson may be right in the sense that, given our knowledge of the diversity of opinion among quite rational men, such as scientists, it would be rather foolish for us to make such constructions.
But there are also purely logical problems with this concept. Using an already relativized concept like this is hardly a suitable way to escape relativism. The difference between a particular audience and a universal audience as constructions is that the former has a real counterpart, so that the image formed by the arguer may thus be more or less adequate. The real audience is either persuaded or not. If our only objective is to reach adherence, then this is the criterion of reasonable argumentation. But the universal audience does not exist except as a construction, and thus it cannot react to the arguments presented to it. What does it mean, then, that the criterion of convincing argumentation is the adherence of a universal audience? Perelman and Olbrechts-Tyteca write that “this refers of course, in this case, not to an experimentally proven fact, but to a universality and unanimity imagined by the speaker, to the agreement of an audience which should be universal, since, for legitimate reasons, we need not take into consideration those which are not part of it.”(1971:31)
This means that a purely imagined unanimity is enough to make the argument convincing, if only the arguer has a legitimate reason to disregard those that he knows would disagree. “The agreement of a universal audience is thus a matter, not of fact, but of right.”(NR 31) Thus if a scholar presents a theory that does not convince everybody in the scientific community, he can claim to have convinced the universal audience (and thus be right) only if he has a legitimate reason to disregard his critics? But what could this reason be? And where does this legitimacy come from?
Usually we do not, in scientific argumentation at least, try to disregard our critics simply by virtue of their stupidity or whatever, but rather we try to see whether their comments are reasonable: Have they understood what we have said? Have they produced genuine counterexamples that would refute our theory? Have they produced empirical evidence that is inconsistent with what we have said, etc.? In order to do this, we shall have to have some idea of reasonable argumentation in science, as well as in practice. But if we already need to know the criteria of sound argumentation before we can decide about the legitimate disregard of our critics, where do we need the concept of universal audience in the first place?
Toulmin’s strategy was equally based on an attempt to dethrown formal logic, and we can understand his preoccupation with the concept ’field of argument’ better in that context. As van Eemeren et. al. have pointed out, the concept was left somewhat vague in his writing, referring sometimes to problem fields (such as weather forecasting or mathematical problem solving), sometimes to sciences or disciplines (van Eemeren et. al. 1996, 155). Be that as it may, the essential meaning of this structure was to introduce the concepts of field-dependent and field-independent criteria of good argumentation: the mistake of traditional logic and epistemology was, according to Toulmin, that the criteria of one field – analytic reasoning or formal logic – have been applied in all fields. “There is no justification for applying analytic criteria in all fields of argument indiscriminately, and doing so consistently will lead one (as Hume found) into a state of philosophical delirium.” (Toulmin 1995, 176)
Toulmin’s objective was apparently to avoid Cartesian scepticism, but unfortunately his strategy will lead the argumentation theorist and practitioner into trouble. If the criteria of good argumentation are not generally field-independent, they will have to be determined in each field. And this is exactly what Toulmin says: “When we ask how far the authority of the Court of Reason extends, therefore, we must put on one side the question how far in any field it is possible for arguments to be analytic: we must focus our attention instead on the rather different question, to what extent there are already established warrants in science, in ethics or morality, in law, art-criticism, character-judging, or whatever it may be; and how far the procedures for deciding what principles are sound, and what warrants are acceptable, are generally understood and agreed.” (ibid.)
Certainly there are such standards in most fields, but the problems that we face in practical situations of argumentation are not only conventional and intra-field but also interdisciplinary, and they also have to do with critizising existing and established criteria of acceptable warrants. For instance, the field of spatial planning has a long tradition and professional culture, and it has been part of this culture to define the acceptable criteria of planning arguments. What will happen when these criteria are critizised by radical planners or plannig theorists, or ecologists, or sociologists, or the local people? Which criteria should prevail, or are there field-independent criteria that could be used in situations like this?
3. The concept of resolving differences of opinion and the pragma-dialectical approach
In contrast to these modern classical approaches, the pragma-dialectical theory of argumentation is deductivist, in the sense that the protagonist of a claim is supposed to be committed to a set of premises making the deduction of his thesis logically valid. I shall not discuss this controversial thesis in this context (for the discussion of deductivism, see e.g. Govier 1987; Berg 1992; Groarke 1992; Woods 1994; Gerritsen 1994; Lapintie 1998), but I shall rather concentrate on the concept of resolution in this theory. Since van Eemeren and Grootendorst do not see the need to depart from analytic reasoning (this being in essence the basis of all argumentation), they, conversely, wish to make a distinction between the normative merits of argumentation in making critical discussion possible, and the empirical or pragmatic merits of rhetorical persuasion. The purpose of argumentation or critical discussion is not the adherence of minds, as Perelman would have it, that is, settling the differences of opinion, but rather resolving them (van Eemeren & Grootendorst 1992, 34).
A dispute is resolved, according to pragma-dialectics, only if somebody retracts his doubts because he has been convinced by the other party’s argumentation, or if he withdraws his standpoint because he has realised that his argumentation cannot stand up to the other party’s critique. Van Eemeren and Grootendorst thus contrast the resolution with the usual ways of getting rid of such conflicts, such as calling on an unbiased third party (a jury, an ombudsman, a judge, or a referee), or negotiating a compromise solution (ibid.). The paradigm case of good argumentation they seem to have in mind is, obviously, scientific discourse, where referees certainly have to be used, but the actual resolution of scientific debates is supposed to be guaranteed only by free and open discussion, where fallacies should be avoided as much as possible. There are no judges or juries in science.
Since this is an empirical or factual criterion, the definition of good argumentation cannot be that it has succeeded in getting the antagonists to retract their doubts or withdraw their conflicting standpoints. This may of course happen for many reasons, for instance out of respect for a reknown scientific authority, or out of an unconscious fear of becoming unpopular, or for any other “unscientific” – though perhaps strategically rational – reason. Resolution, defined in this way, is therefore not tantamount to truth or the best policy decision, if one wants to avoid the problematic consequencies of cognitive and moral relativism. But if so, then one may wonder whether there is such a great difference between settling and resolving differences of opinion, although van Eemeren and Grootendorst present it as a demarcation line.
If we consider the solution to a mathematical problem, the criterion cannot be the adherence of the minds of mathematicians, nor the willingness of critics to retract their doubt, but it must be a real solution. Correspondingly, the absence of unanimity is no criterion for the failure of the suggested solution, if the proof is valid, and no one can find any mistake in it. Is it really not possible that something of this kind is also meant by the practitioners trying to find solutions to social, political, ethical, or planning problems? Not simply unanimity, but the real, or at least a good enough solution?
In that case van Eemeren’s and Grootendorst’s definition of resolution is somewhat counter-intuitive. We might, of course, understand this as the empirical element of resolution (say solution1), and do the usual philosophical idealization trick to arrive at the ’real’ solution (solution2). The differences of opinions would thus be ’really’ resolved, if the parties would in their debate conform to all of the rules of critical discussion specified by the pragma-dialectical theory (ibid. 202-209). Thus the above mentioned examples about the uncritical scientific audience would not be examples of critical discussion, since fear and too great respect for authority should not affect the proceedings of critical discussion.
Could we go as far as assuming solution2 to be tantamount to truth, or the best solution to a political or social problem? This would be a much more promising idea than the cognitive relativism lurking behind the rhetorical or constructivist conceptions of solution? But this would not do, at least not without additional rules of critical discussion on top of the ten specified by van Eemeren and Grootendorst (ibid.). The problem is, namely, that these rules are meant to create the precondition of free presenting, defending and challenging of standpoints, if the parties wish to do so. There is no rule requiring the antagonist to challenge a standpoint that is not warranted, or the protagonist to present arguments if nobody has casted doubt on the standpoint. Thus we may imagine a communicative situation where, for social or cultural reasons, no one wishes to create a controversial situation. In a community like that, solution 2 will not necessarily represent truth or the best policy option. It is perfectly possible for such a community to end up, for instance, in a development that will cause disastrous environmental consequen-ces. ’Real’ solution would thus represent a third type, say solution3.
4. Solutions and the Communicative Theory of Planning
Although our original attempt to define the ’real’ solution is still unanswered, this distinction between solution1, solution2 and solution 3, would perhaps help to clarify the somewhat vague conceptual scheme that planning theorists are putting forward. Consider the following description of the the so-called inclusionary approach to argumentation in planning:
“The challenge for an inclusionary approach to strategic spatial planning is to experiment with, and test out, strategic ideas in initially tentative ways, to ’open out’ possibilities for both evaluation and invention of better alternatives, before allowing a ’preferred’ discourse to emerge, and ’crowd out’ the alternative. This suggests that a discursive process needs to be designed which explicitly explores different ’storylines’ about possible actions and offers up different ’discursive keys’ for critical attention, maintaining a critical attitude until there is broad support for a new strategic discourse. Having thus generated a knowledgeable consensus around a particular storyline, the task of consolidating the discourse and developing its implications can then proceed. The discourse community can be said by this time to have collaboratively chosen a strategy, over which they are then likely to have some sense of ’ownership’. A new ’cultural community’ has been formed around the strategy.” (Healey 1997, 278-279).
What kind of solution are we talking about here? Communicative planning, according to Healey, would seem to consist of the following steps:
1. opening up the discourse, in order to allow the different alternatives, meanings and visions to come forward,
2. closing it down again through a careful timing and consensus-formation and
3. forming a new “cultural community” around the chosen strategy.
The problem is, however, that the theory still does not address the two original questions that were mentioned earlier:
1. why would the participants finally give up their differences of opinion concerning, for instance, a planned motorway through a residential area,
2. even if they do, is this a guarantee for its being the right solution in any sense of the word? Since unanimity is not the basic social feature of a large community, and, as we saw, it does not even produce truth or the best solutions to problems, then what kind of consensus-formation are we talkin about? A rhetorical success? Or is it at all possible to arrive at such a “cultural community” after a successful opening up of real alternatives?
In its essence, Healey is describing a solution1, since the participants are not forced to arrive at a specific desicion, nor do they use an unbiased third party for arbitration. But it is not only that, since the organizer of the process, the ’communicative planner’, is supposed to take care that all the strategic ideas and possibilities are called for evaluation, and that a “critical attitude is maintained until there is broad support for a new strategic discourse.” There are, thus, many elements of critical discussion present in this description, but they are mainly concentrated on the opening phase, by removing obstacles of free discussion. The “consolidation” or consensus-formation remains a black box.
In order to arrive at a solution2, the other resouces of argumentation should be taken to use, in the sense that participants would learn to challenge the relevant alternatives and defend their standpoints with relevant arguments, but also to develop readiness to alter and even to reject their standpoints, if they cannot be defended. The strategy of communicative planning could thus be described as a turn from expert-oriented planning and solution1 towards solution 2. Although this will not guarantee that the best solution (solution 3) is reached, it is still the best available option for the reflective practitioner.
Aristotle (1924). Rhetoric. W.D.Ross (ed.). Oxford: Clarendon Press.
Berg, J. (1992). Validity and Rationality. In: Eemeren, Frans H. van & Grootendorst Rob & Blair, J.A. & Willard, C.A. (eds.) (1992) Argumentation Illuminated. Amsterdam: SicSat.
Eemeren, Frans H. van & Grootendorst, Rob (1992). Argumentation, Communication, and Fallacies: A Pragma-dialectical Perspective. Hillsdale, NJ:Lawrence Erlbaum.
Eemeren, Frans H. van & Grootendorst, Rob & Henkemans, Francisca Snoeck (1996). Fundamentals of Argumentation Theory.
A handbook of Historical Backgrounds and Contemporary Developments. Mahwah, New Jersey: Lawrence Erlbaum Associates.
Fischer Frank & Forester, John (eds.)(1993) The Argumentative Turn in Policy Analysis and Planning. Duke University Press.
Forester, John (1989) Planning in the Face of Power. Berkeley, California: University of California Press.
Gerritsen, S. (1994) A Defence of Deductivism in Reconstructing Unexpressed Premises. In: Eemeren, Frans H.van & Grootendorst, Rob (eds.)(1994) Studies in Pragma-dialectics. Amsterdam: SicSat.
Govier, T. (1987) Problems in Argument Analysis and Evaluation. Berlin: De Gruyter.
Groarke, L. (1992) In Defence of Deductivism: Replying to Govier. In: Eemeren, Frans H. van & Grootendorst Rob & Blair, J.A. & Willard, C.A. (eds.) (1992) Argumentation Illuminated. Amsterdam: SicSat.
Healey, Patsy (1997) Collaborative Planning. Shaping Places in Fragmented Societies. Hong Kong: Macmillan Press.
Lapintie, Kimmo (1998) Analysing and Evaluating Argumentation in Planning. Environment and Planning B: Planning and Design, vol. 25, n:o 1, 187-204.
Perelman, Chaïm & Olbrechts-Tyteca, Lucie (1971) The New Rhetoric. A Treatise on Argumentation. Notre Dame, Indiana: University of Notre Dame Press.
Sager, Tore (1994) Communicative Planning Theory. Aldershot, Hants: Avebury.
Toulmin, Stephen (1995) The Uses of Argument. Cambridge: Cambridge University Press.
Woods, J. (1994) Missing premises in pragma-dialectics, Logique et Analyse, vol 33, 155-168.