Radical Constructivism

Central to the field of education is the concept of learning. Learning is something we all experience, and although individuals outside of the education field may not meditate on learning daily, philosophers and authors have long pondered the subject. From Plato’s Allegory of the Cave to Skinner’s Walden Two to Illich’s Deschooling Society, thinkers have proposed mechanisms for learning which imply and reflect larger sociological and ontological understandings. In my recent research around teacher learning and professional development, I have found it theoretically rich to utilize a radical constructivist framework. A few fellow students have mentioned working with constructivism, so I thought I would take this space to present a short statement on my use of the radical interpretation.

The framing of learning as knowledge construction has been present in the field of education for over a century, greatly shaped by the works of Dewey (1938), Piaget (1954/2013), and Vygotsky (1978), among others. In the 1970s and 1980s von Glasersfield (1974, 1989) helped develop radical constructivism, a school of thought that posits that not only is knowledge built by the individual, but that this construction and adaptation of knowledge constitutes what is known by the knower, rather than knowledge of an outside objective truth (Lerman, 1989). As pointed out by Gash (2014), the conversations in constructivist learning theory have shifted to focus on the centrality of interpersonal interaction in the process of knowledge construction, as described by Vygotsky (1978). However, I am persuaded to agree with Steffe and Thompson (2000) who argue that an individual’s interaction with external structures and his or her interpretations of those interactions are key components to knowledge construction in the radical paradigm. The focus on the person-to-person interaction in social constructivism constitutes a subset of intersubjective experiences that contribute to the construction of knowledge in the radical interpretation (Riegler & Steffe, 2014; Steffe & Thompson, 2000).

The radical perspective extends the concept of equilibration put forth by Piaget (1977). Equilibration contends that there are interactions between the parts of a person’s knowledge and their total body of knowledge at any given moment, and that “[t]here is a constant differentiation of the totality of knowledge into the parts and an integration of the parts back into the whole” (Piaget, 1977, p. 11). Radical constructivism elaborates on this conception of equilibration by arguing that these constructions are not interpretations or approximations of an external objective reality that the knower came to know, but rather constitute reality for the knower (Lerman, 1989). The theory of knowledge then is based on two principles: (1) knowledge is not passively received but actively built up by the cognizing subject; and (2) cognition is adaptive and serves the organization of the experiential world, not the discovery of ontological reality (von Glasersfeld, 1989, p. 162).

Radical constructivism puts the individual’s interactions, interpretations, and equilibrations with all externalities at the center of knowledge construction. This theory of learning has implications for the nature of reality; an objective reality cannot come to be known, so positivist and post positivist positions are untenable. For teachers engaging in professional development, discussions involving one’s conceptualization of reality rarely occur, due to the practical nature of the work. However, the idea that they build their knowledge through their interactions with each other, students, technology, their school context, parents, etc., is a useful in their professional work as it provides guidance for action to promote learning. As a researcher, the radical constructivist perspective a useful lens to bring structure to interpretations of what is going on, and how learning is occurring through professional development. This lens has brought a useful and meaningful angle to my work in this domain.



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Gash, H. (2014). Constructing constructivism. Constructivist Foundations, 9(3), 302–310.

Lerman, S. (1989). Constructivism, mathematics and mathematics education. Educational Studies in Mathematics, 20(2), 211–223. http://doi.org/10.1007/BF00579463

Piaget, J. (1954). The construction of reality in the child (Vol. 82). Routledge.

Piaget, J. (1977). Problems of equilibration. In M. H. Appel & L. S. Goldberg (Eds.), Topics in Cognitive Development (pp. 3 – 13). Boston, MA: Springer US. Retrieved from dx.doi.org/10.1007/978-1-4613-4175-8_1

Riegler, A., & Steffe, L. P. (2014). “What Is the teacher trying to teach students if they are all busy constructing their own private worlds?”: Introduction to the special issue. Constructivist Foundations, 9(3), 297–301.

Steffe, L. P., & Thompson, P. W. (2000). Interaction or intersubjectivity? A reply to Lerman. Journal for Research in Mathematics Education, 31(2), 191. http://doi.org/10.2307/749751

von Glasersfeld, E. (1974). Piaget and the radical constructivist epistemology. In C. D. Smock & E. von Glasersfeld (Eds.), Epistemology and education (pp. 1–24). Athens, GA: Follow Through Publications. Retrieved from http://www.vonglasersfeld.com/034

von Glasersfeld, E. (1989). Constructivism in education. In T. Husen & T. N. Postlethwaite (Eds.), The international encyclopedia of education, supplement (Vol. 1, pp. 162 – 163). Oxford/New York: Pergamon Press.

Vygotsky, L. S. (1978). Mind in society : the development of higher psychological processes. (M. Cole, V. John-Steiner, S. Scribner, & E. Souberman, Eds.). Cambridge: Harvard University Press. Retrieved from http://www.psy.cmu.edu/~siegler/vygotsky78.pdf