Aspects of Radical Constructivism and
Its Educational Recommendations
Ernst von Glasersfeld University of Massachusetts
In the context of theories of knowledge, the term constructivism
was introduced by Jean'Piaget and became widely known through the
publication of one of his major Works, The Construction of Reality in the Child
(La Construction du Reel chez l'eltfant, 1937).
In the
United States, Piaget became known mainly for his stage theory of cognitive
development. Some thirty years later, when he was being discovered for the
second or third time, "constructivism" became a catchword and was
used by thousands who had not the
least interest in Piaget's epistemological considerations
and therefore missed the meaning he
intended when he spoke of construction. T6 most it seemed to mean no more than
that the child does not appropriate adult knowledge in one piece and
therefore has to construct it bit by bit. Having to teach cognitive psychology at that time, I came to characterize this
superficial approach as "trivial," and explicitly
differentiated the interpretation of Piaget's neo-Kantian
theory of knowledge as "radical constructivism."
This constructivism is radical because it
breaks with the Western epistelnoloical tradition. It is an
unconventional way of looking and therefore requires conceptual change. In
particularadical constructivism requires the change of several deeply
rooted notions, such as knowledge, truth, representation, and reality. Because the dismantling of traditional ideas is
never popular, proponents of radical constructivism are sometimes considered to
be dangerous hsreticsr
Some of the critics persist in disregarding conceptual differences that have been explicitly stated and point to
contradictions that arise from their attempt
to assimilate the constructivist view to traditional epistemological assumptions.
This is analogous to interpreting a quantum-theoretical physics text with the
concepts of a 19th-century corpuscular theory.
It may be useful, therefore, to reiterate some points of our
"postepistemologi‑
cal" approach.' Let me begin with a term that
was brought up several times in our
discussion at the meeting, namely, representation. Goldin suggested that behaviorism had erred by rejecting the notion
of an ort.4nism'_s_interaalpnstrtiC5and
that constructivism
would be making an analocous mistake if it rejected the notion of external constructs
(cf. Goldin, 1990). Given the
notorious ambiguity of the English
word representation (cf. von Glasersfeld, 1987). an explanation seems in order. Constructivism does reject the use of the
word in the sense of traditional philosophers who intended it to mean a
conceptual structure that was in some way isomorphic
with a part of ontological reality. However, this leaves at least two meanings of
"representation" that constructivism does not reject: (,the Piagetian sense that refers to a
re-presentation (from memory) of an experience
one has had at some earlier moment; and (2) the sense that Kaput (1991)
has so expertly discussed in the context of "mtirt-iple
representations," which refers to
graphic or symbolic structures that provide the cognizing subject with the opportunity to carry out certain mental
operations. Constructivists, too, therefore
speak of a certain painting as a representation of a bunch of sunflowers, or of
the symbols "f(x)" as the representation of a function. It is worth
noting, however, that in these cases,
the graphic or symbolic structure merely provides an opportunity to
replay certain perceptual or conceptual operationF.
NO EXIT FROM SUBJECTIVITY
Radical
constructivism is an attempt to develop a theory of knowing that is not made
illusory from the outset by the traditional assumption that the cognizing activity should lead to a "true"
representation of a world that exists in itself and by itself, independent of
the cognizing agent. Instead, radical constructivism assumes that the cognizing activity is instrumental
and neither does nor can concern anything but the experiential world of the
knower. This experiential world is
constituted and structured by the knower's own ways and means of perceiving and conceiving, and in this elementary
sense it is always and irrevocably subjective (i.e., construed by the
cognizing subject). It is the knower who segments
the manifold of experience into raw elementary particles, combines these to form viable "things," abstracts
concepts from them, relates them by means
of conceptual relations, and thus constructs a relatively stable experiential reality. The viability of these concepts and
constructs has a hierarchy of levels that begins with simple
repeatability in the sensory-motor domain and turns, on levels of higher
abstraction, into operational coherence, and ultimately concerns the
noncontradictoriness of the entire repertoire of conceptual structures.
The statement that the construction of the
experiential world is irrevocably
subjective has been interpreted as a declaration
of solipsism and as the denial of any "real" world. This is unwarranted.
Constructivism has never denied an ulterior
reality; it merely says that this reality is unknowable and that it makes no sense to speak of a representation of
something that is inherently inaccessible.
The insistence on the subjectivity of the
experiential world has also led ..,,me critics
to the rash conclusion that radical constructivism ignores the role of social interaction in the construction of knowledge.
This, too, is a misinterpretation, and
a rather thoughtless one. If one begins with the assumption that all knowledge is derived from perceptual and conceptual
experience, one in no way denies that "others" and
"society" have an influence on the individual's cognitive constructing. On the contrary, because others add up
to a major part of the individual's experiential environment, they will have a
considerable role in determining which
behaviors, concepts, and theories are considered "viable" in the
individual's physical and linguistic
interactions with them. Nevertheless, as a constructivist, one will remain aware of the fact that these
others and the society they constitute
"exist" for the individual subject only to the extent to which they
figure in that individual's
experience—that is to say, they are for each subject what he or she perceives
and conceives them to be.
In contrast, those who call themselves social
constructionists tend to introduce the
social context as an ontological given. They are, of course, free to do so, but
it does not entitle them to fault another school of thought that
endeavors to build a theory of knowing
without ontological givens or other metaphysical assumptions. This was seen quite clearly 60 years ago by
Alfred Schutz (1932/1974) when he referred to "the immensely diffitult
problems that are tied to the constitution
of the thou in each individual's own subjectivity" and added a few
lines later that "such analyses belong to the general theory of knowledge
and thus mediately to the social
sciences" (p. 138). Radical constructivism is indeed intended as a theory of knowing and therefore is
obliged to attempt an analysis of how the thinking subject comes to have others
in his or her construction of the experiential
world (cf. von Glasersfeld, 1986, 1995).
SOME SALIENT CHARACTERISTICS
From the radical
constructivist point of view, the basic ideas concerning the questions what is knowledge and how do we come
to have it can be summarized as follows.
No philosopher in the course of the last 2,500
years has been able to demolish the
skeptics' logical arguments that the real world, in the sense of ontological reality, is inaccessible to human reason. In view of this impasse,
onstructivism, like the pragmatists
at the beginning of our century, suggests that we change the concept of knowledge. The pragmatists, however,
remained attached to a meta‑
physical if not material form of realism. Instead,
constructivism goes back to Vico, who considered human knowledge a human
construction that was to be evaluated according to its coherence and its fit
with the world of human experience,
and not as a representation of God's world as it might be beyond the interface
of human experience. Constructivism drops the requirement that knowledge be "true" in the sense that it
should match an objective reality. All it requires of knowledge is that it be viable, in that it fits into the
world of the knower's experience, the
only "reality" accessible to human reason.
With regard to the cognitive construction, we
follow the two pioneers of conceptual
analysis, Jean Piaget and Silvio Ceccato. That is to say, we attempt to build plausible models of hoW, by means of
reflection and abstraction, viable concepts
could be derived from subjective experience.
This change of view
has consequences not just for a few traditional philosophical beliefs but for
almost everything one habitually thinks about acts of knowing and the
knowledge resulting from them. Here I want to mention only two cases in point.
Inherent in radical constructivism is the
realization that no knowledge can claim uniqueness. In other words, no matter
how viable and satisfactory the solution to a problem might seem, it can
never be regarded as the only possible solution.
(Note that this does not contradict the observation that, for instance in mathematics, solutions are often fully determined
by the operitions one carries out to
find them.)
The second is Leo Apostel's admonition that
"a system Mould always be applied
to itself" (Inhelder, Garcia, & Voneche, 1977, p. 61).•1n our case,
this leads to the conclusion that
radical constructivism cannot claim to be anything but one approach to the
age-old problem of knowing. Only its application in contexts where a theory of
knowing makes a difference can show whether or not it should be considered a viable approach.
CONCERNING EDUCATION
In this volume, we are
not primarily concerned with philosophical questions, but rather with applications to the teaching of
mathematics. In this regard, let me emphasize
that although we have promising beginnings (cf. Steffe, 1991; Steffe & Cobb, 1988; Steffe, von Glasersfeld,
Richards, & Cobb, 1983; von Glasersfeld,
1981, 1992), the enormous task of analyzing the basic conceptual steps in the construction of mathematics has barely•begun.
Teachers at all levels, from elementary school to
postgraduate instruction. have to
rely on the use of language, and textbooks cannot do without it. Yet in my experience, few language users have given much
thoughtsto the question how linguistic communication is supposed to work.
In everyday circumstances, where most of what we
say and others say to us does not give
rise to obvious misinterpretation, we usually assume that the
meaning of words and sentences is the same for all
speakers of the particular language.
If there are differences, they seem to be insignificant. I have shown elsewhere that, even in the case of the most
ordinary objects, the notion of "shared
meaning" is strictly speaking an illusion. This is so because we associate
the sounds we come to isolate as
"words" not with things but with our subjective experiences of things—and although subjective
experiences may be similar for different subjects, they are never quite
the same (von Glasersfeld, 1990). Sharing meaning,
ideas, and knowledge, therefore, is like sharing an apple pie or a bottle of wine: None of the participants can taste the share
another is having.
THE MAKING OF ABSTRACTIONS
Here, however, we are
concerned with mathematics teaching and thus not with sensory items but with concepts that are abstracted
from mental operations. In the case of
ordinary sensory objects, the individual gradually learns, by interacting
in practical situations with other speakers of the language, to adjust his or
her meanings so that they become more or less compatible with those current in
the community. In the case of abstract items,
however, it is far more difficult to achieve
this social adequation, because the occasions where conceptual discrepancies might come to the surface are few and far
between. Hence, in order to teach
abstract notions, it is indispensable for the instructor to generate experiential situations for the students, such that they
themselves can make the necessary abstractions.
In order to foster such abstractions, the teacher must be successful in establishing with the students a common
language, that is, a language of carefully
negotiated and coordinated meanings or, as Maturana has called it, a consensual domain (Maturana, 1980; Richards,
1991).
Mathematics is the result of abstraction from
operations on a level on which the sensory or motor material that provided the
occasion for operating is disregarded. In arithmetic this begins with the
abstraction of the concept of number from
acts of counting. Such abstractions cannot be given; they have to be made by the students themselves. The teacher, of
course, can help by generating situations
that allow or even suggest the abstraction. This is where manipulables can play an important role, but it would be naive
to believe that the move from handling
or perceiving objects to a mathematical abstraction is easy, let alone automatic. The sensory objects, no matter how
ingeniously they might be designed, merely offer an opportunity for
actions from which the desired operative concepts
may be abstracted; one should never forget that the desired abstractions, no matter how trivial and obvious they might seem
to the teacher, are never obvious to
the novice.
The same can be Said about the use of multiple represenmtio.ns (Gerace, in press; Kaput, 1991). In learning to switch from one representation to
another, an act of
reflective abstraction may focus on what it is that appears to remain the
same. But this abstraction is, again, not
automatic, and it may well be precluded if the switch is explicitly presented
as the simple exchange of two equivalent items. The point is that the representations are different, but an
operative concept or conceptual
relation they embody is considered the same.
MEANING AND MISCONCEPTIONS
In contrast, the need
for an experiential basis for the abstraction of concepts is often overlooked,
because of the formalist myth that all that matters in mathematics is the manipulation of symbols. This
ignores the fact that spoken words or marks
on paper are symbols only if one attributes to them something they symbolize, that is, a meaning—and meaning is always
conceptual. As Hersh wrote,
"Symbols are used as aids to thinking just as musical scores are used as aids to music. The music comes first, the score
comes later" (1979-1986, p. 19). There
is little point in teaching a score to students who have no music to relate to it. In school, however, mathematical symbols are
often treated as though they were self-sufficient and no concepts and mental
operations had to accompany them.
Hence, when students are only trained to manipulate marks on paper, it is small wonder that few of them ever come to
understand the meaning of what they are
doing and why they should do it.
Because there is no way of transferring meaning,
that is, concepts and conceptual
structures, from one head to another, teachers, who have the goal of changing something in students' heads, must have
some notion.of what goes on in those other heads. Hence it would seem necessary for a teacher to
build up a model of the student's
conceptual world (see von Glasersfeld & Steffe, 1991).
From the constructivist perspective, it is not
helpful to assume (maybe on the basis of -wrong"
answers) that a student's ideas are simply miRconceptions that have to be replaced by the conceptions that arc
considered correct by mathematicians,
physicists, or other experts. In order to become operative in a student's thinking., a new conception must be related to
others that are already in the student's
repertoire. No doubt there are several ways of establishing such relationships,
but the simplest and most efficacious arises when the new structure is built out of elements with which the students are
familiar. In other words. students
must be shown that there are elements in their experience that can be related differently from the way they habitually
relate them; to make such changes
desirable to students, they must be shown that the new way provides advantages
in a sphere of living and thinking that reaches beyond passing exams and getting good grades.
Besides,
when a student has struggled to find an answer to a given problem. it is not only boorish but also counterproductive to
dismiss its "wrong," even if the
teacher then shows the "right" way of proceeding. Such disregard for the student's effort inevitably demolishes the
student's motivation. Instead, a wiser
teacher will ask the student how he or she came to the particular answer.
In the majority of cases, the student, in
reviewing the path (i.e., reflecting on the operations carried out), will either discover a hitch
or give the teacher a clue to a conceptual
connection that does not fit into the procedure that is to be learned, The first is an invaluable element of learning: It
provides students with an opportunity to realize that they themselves can see
what works and what does not. The second provides the teacher with an insight
into the student's present way of
operating and thus with a clearer idea of where a change might be attempted.
To end this brief list of
recommendations, let me repeat a rather unpopular point. From the
constructivist perspective, whatever one intends to teach must never be
presented as the only possible knowledge—even if the discipline happens to be
mathematics. Indeed, it should be carefully explained that a fact such as
"2 + 2 = 4" may be considered certain, not because it was so ordained
by God or any other extra-human authority, but because we come to construct
units in a particular way and have agreed on how they are to be counted.
Radical constructivism, as I have
often said, makes no claim to novelty. Its basic ideas can all be found along the
wayside of Western philosophy, but to my knowledge, they have never been put
together with the intent to create a viable model of the cognitive activity. Claude
Janvier was perfectly right when he commented in his contribution that
constructivism does not tell us (as teachers) what to do (cf. Janvier, chapter
25, this volume) and I can only repeat my answer, that in my view, constructivism
does tell the teacher a few things that should not be done.
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