The Role of Metaphor in Scientific Epistemology: A Constructivist Perspective and Consequences for Science Education

I examine the role played by metaphor, in supporting andconditioning our thinking about theoretical models of learning in science education.Some examples are given, of cases where the use of inappropriate metaphors can actually counteract a properunderstanding of the topic being learnt. With special reference to von Glasersfeld's theory of radicalconstructivism, it is argued that much of the controversy appearing in the academic discussion of this theorystems from the injudicious use of metaphors of ``truth' and ``reality', concepts that are in a sense inheritedfrom the domain of Law. These metaphors are often taken too literally, as representing ``obvious' and henceindisputable constraints on scientific investigation; and they then strongly favour the adoption of an epistemologyof scientific realism, which is at variance with the theory of knowledge that is proposed by radical constructivism.However, it is argued that this realist epistemology is not compelling, since it rests on a somewhat contentiousmetaphoric base, and that a radical-constructivist epistemology offers a better strategy for the purposesof science education.