Metaphors in Knowledge and Metaphors of Knowledge: Notes on the
Constructivist View of Learning
CARLO TARSITANI University of Rome "'La Sapienza"
ABSTRACT: As the scientific change problem is at the center of epistemological research, the conceptual change problem is widely discussed in didactical research. In this paper common features of both problems will be discussed. Recent ideas on the role of analogies and metaphors in the growth of scientific knowledge are analyzed in order to show their relevance for scientific education problems. These ideas are also confronted with the image of scientific learning put forward by pedagogical and epistemological eonstrtmtivism. In this perstxx~tive, the analysis of Maxwelrs views about metaphors and analogies seems to give a deeper insight as to the problem of scientific change and scientific abstraction which still require clarification in educational and epistemological reflection.
KEYWORDS: Abstraction, accommodation, analogy, assimilation, conceptual change, construetivism, growth of knowledge, history, learning, metaphor.
Introduction: The Scientific Change Problem
One of the main factors of the present crisis of the standard image of science, that is the empiricist-inductivist image of science stated essentially by the neopositivistic school (and also widespread in a simplified version among scientists, science teachers, and science textbooks) is its inability to cope with scientific change. Here scientific change means, in a very general fashion, the transformation of the criteria of explanation and description of phenomena, that is the emerging of the new in science, as is usually stated in terms of a new way of seeing old things or, more radically, seeing new things in the place of the old ones. In particular, this idea embodies the birth of new concepts or the meaning variance of the old ones, that is conceptual changes in general.
The classical distinction between the context of discovery and the context of justification confined scientific change (seen simply as discovery) to an irrational, psychological zone, inaccessible to logical analysis - while postulating that procedures based on apparently neutral empirical data were available for its
Interchange, Vol. 27/1, 23-40, 1996. Kluwer Academic Publishers. Pdnted in the Netherlands.
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subsequent logical justification. Indeed, in the traditional view of teaching, a justification of the same kind is considered as a sufficient reason for learning, where learning is conceived as the result of adding new information to a previously empty mental space.
Now, the dogma "the process of change in science is irrational" seems to persist even in postmodem, or relativist representations of science in progress (Laudan, 1990).
In the first representations of science to diverge from the justificationist model and to gain a wide audience - that is, on the one hand, Popper's falsificationism and, on the other hand, Kuhn's historical relativism - the dynamic or historical character of science became central. The Popperian logic of research, however, excluded a logic of discovery, discovery being considered a free creative act of the imagination. Kuhnian scientific revolution was metaphorically described as a collective gestaltic change, or a kind of religious conversion, not easily analyzable in rational terms. Moreover, the meaning variance problem seemed to undermine any objectivistie- rationalistic view of the growth of knowledge.
So both Pepper's and Kulm's images of science share with the standard image of science an inherent incapability to deal with the process of conceptual change. Thus, if the history of science is indeed a history of processes of conceptual change, the essential tension between history and philosophy of science cannot be relaxed. Similarly, in recent developments in educational theory, the learning process is conceived as a change from conceptions that preexist in the learner's mind, so therefore the idea of the irrationality, or illogicality, of conceptual changes becomes a serious obstacle to a clear statement of educational strategies. For instance, Nussbaum (1989) sees a strong correlation between the new view of scientific change triggered by the works of Popper, Kulm, Lakatos, and Toulmin and the spreading of the constructixdst fashion both in epistemology and in science education, and claims that this is the main reason why the concepttml change problem has become central in educational research.
To find a systematic attempt to give a rational foundation to the description of change, we have to go back to classical German philosophy, that is to the idealistic, then historical materialistic view of the Hegel-Marx-Engels philosophy. In this, dialectical logic was a general scheme to encompass the essentially historical character of human, social, and intellectual evolution. The general metaphysical character of dialectics was denounced by Popper as being too generic, all the more suspect because it was able to cope with everything that might happen in history: indeed, the dialectical model leads to a kind of historical justificationism, inasmuch as everything in history must follow a rational post hoc plan. I think, however, that some of the present attempts to give a representation of scientific change resemble some aspects of the dialectical view.
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Currently the most common form of representation of historical change in scientific schemes uses the evolutionary metaphor. Popper too described his view" of science as evolutionary, scientific change being analogous to Darwinian casual mutations, that should be thereafter subjected to severe selection by the experimental environment (Popper, 1976).
The evolutionary metaphor brings us to recent trends both in the theory of knowledge and in the theory of leaming, namely the contructivistic theory of knowledge, with its assumption of a parallelism in the process of growth of knowledge both for a learning individual and for scientific communities. In this theory, acquisition of knowledge is seen as a progressive adaptation of mental constructs, cxmceptions, or representations in continuous interaction with the environment)
However it is worth noting that, while Popper emphasizes the struggle for life and the natural selection of altemative hypotheses, constructivists insist on the conservationist effort of mental constructs to preserve their individuality in the face of extemal and internal perturbations. This idea, in effect, provided the basis for the constructivist movement, in Piaget's genetic epistemology (Piaget, 1970), where a rich and nontrivial image of the growth of knowledge is founded on a highly developed evolutionary metaphor. Indeed, from Piaget's point of view, epistemology itself tends to become a part of a complex evolutionary process that includes the psycho-biological behavior of human beings. Adopting most of Piaget's theses, pedagogical and epistemological constructivism attributes to the knowing-operating (i.e., experiencing) subject to the spontaneous tendency to preserve viable representations of the world in a changing environment (Glasersfeld, 1989).
I think that Piaget's view (and, consequently, the constructivist view) can be further developed: in particular, the problem of conceptual change deserves better attention, since without a full theory of conceptual change Piaget's genetic epistemology may appear to retain a justificationist view of the growth of knowledge. In fact Piaget saw the growth of knowledge as a process towards necessary conceptual structures that are thus, in a certain sense, absolutised. At the same time, and for analogous reasons, because it lacks an explicit analysis of the dynamic of mental constructs, the constructivist vision tends to assume the flavor of a conservative version of classical conventionalism. 2
In the following I will discuss the cognitive role of metaphor and try to resolve, at least partially, the above shortcomings. In speaking of metaphor, I will be concerned with the main result of analogical thinking, in the sense that the discovery of an analogy becomes scientifically productive when the analogy implies a transfer of conceptual schemes bringing a metaphorical description to the field of phenomena seen in an analogical way.
Pointers will be taken fi'om the recent debate on analogy and metaphor in epistemology and the history of physics. I will deal in particular with Maxwelrs ideas on the function of analogies and metaphors in the development of knowledge. I think that through this analysis it is possible to enrich both the pedagogical and
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epistemologic~ aspects of the constnlctivist view. The main issue is this: how can the essential function of metaphors in scientific change be incorporated into the evolutionary metaphor used by the constructivist movement to depict both the individual's and the scientific community's growth of knowledge? And, eventually, what kind of suggestions earl be made, on the basis of this, regarding pedagogical constructivism? 3
The Role of Metaphor From the Epistemological Point of View
Various recent works have stressed the importance of the role of metaphors in the growth of scientific knowledge. I will discuss what I consider to be the most promising line of thought: that stemming from Max Black's interactive conception of metaphor (Black, 1962), and developed in particular by Mary Hesse's and Stephen Boyd's approaches to the role of metaphors, analogies, and models. Both have seen in the use of metaphors and in the related use of analogies and models a way to represent the intrinsic dynamics of scientific knowledge, which is so difficult to describe through rational representations.
Let us state briefly, using Hesse's words, this interaction view of metaphors. The traditional views of the function of metaphors stressed their substitutive role. Starting from two systems, the primary and the secondary (each supposed to be describable in literal language), a metaphorical operation consists of a description of the primary system in words normally used in connection with the secondary system, Obviously, in this substitutive use of metaphors, some kind of similarity or analogy between the two systems is presumed. Then, on the basis of this analogy, one can infer that some further properties of the secondary system may find their correlate in the primary one (this is the classical "argument by analogy"). Starting from Black's analysis, Hesse claims that there are at least two respects in which such a conception of a metaphor may be insufficient. First, since "the metaphor works by transferring the associated ideas and implications of the secondary to the primary system" (Hesse, 1966, pp. 162-163), it may produce a change also in the description of the secondary system. As Hesse says,
in accordance with the doctrine that even literal expressions are understood partly in terms of the set of associated ideas carried by the system they describe, it follows that the associated ideas of the primary are changed to some extent by the use of metaphor and that, therefore, even its original literal description is shifted in meaning. The same applies to the secondary system, for its association come to be affected by assimilation to the primary [italics added]. (1966, p. 163 )
In this sense metaphor is not only a comparison between two systems, but it also creates a semantic resonance between them, that is an interaction between their conceptual representations.
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Second, it may happen that the metaphor itself creates the similarity: it gives a new way of looking at a primary system, making it possible to see new essential features of it.
The main argument used by Hesse is based on a critique of the hypothetical- deductive conception of scientific explanation (the covering law deductive model), in the sense that every genuine explanation, constructing a model of the system to be explained, actuaUy gives a metaphorical transcription of the explanandum domain by changing its meaning.
Thus metaphors are very important factors in conceptual change. As Hesse states, the interaction view sees language as dynamic: an expression initially metaphoric may become literal (a "dead" metaphor), and what is at one time literal may become metaphoric ....What is important is not to try to draw a line between the metaphoric and the literal, but rather to trace out the various mechanisms of meaning-shift and their interaction. (1966, p. 166)
Leaving aside tlesse's defense of the function of models (against the purely formal view of theories), as nontrivial ways to give theories a real predictive power and to enlarge their phenomenic field of application, let us continue to develop the function of metaphors in scientific change.
It is here that Boyd's contribution becomes relevant. Boyd criticizes the view that the function of metaphors lies in a pretheoretical stage of the development of a discipline, or, for mature sciences, in heuristics, pedagogy, or informal exegesis. He instead argues that there exists an important class of metaphors that play a constitutive role. More precisely, there are "cases in which there are metaphors which scientists use in expressing theoretical claims for which no adequate literal paraphrase is known" (Boyd, 1979, p. 360). One of the examples quoted by Boyd is the representation of the brain's behavior in the terminology of computer science.
Indeed, a metaphorical description may function as a sort of catachresis, that is, it may be used to introduce theoretical terminology where none previously existed. The open-endness of metaphors of this kind, given that they are unable to precisely specify the relevant aspects of similarity or analogy, is for Boyd a very important factor in theory change.
Indeed, the utility of theory-constitutive metaphors seems to lie largely in the fact that they provide a way to introduce terminology for features of the world whose existence seems probable, but many of whose fundamental properties have yet to be discovered. Theory-constitutive metaphors, in other words, represent one strategy for the accommodation of language to as yet undiscovered causal features of the world [italics added]. (1979, p. 364)
The use of constitutive metaphors of this kind, including those specialized metaphors that we call models, demonstrates the tension that exists between the "it is so" and the "it is not so" that is typical of analogical thinking. 4 Moreover, terms like "assimilation" (Hesse) and "accommodation" (Boyd) lead us back to Piaget's theory of cognitive processes.
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In Piaget's complex representation of the growth of knowledge, as in that of his constructivist followers, the evolutionary metaphor appears to be constitutive in the Boydian sense. Speaking of the cognitive process, Piaget uses...