Abstract
The starting point of this article is a thought experiment devised independently by Vygotsky and Piaget: From a developmental point of view, what would it be like to live in a society of exact contemporaries, such as children of the same age? Vygotsky’s negative answer contrasts with Piaget’s more positive one. One reason why their answers diverge is that although transmission and transformation are central processes for both Piaget and Vygotsky, they are differently interpreted in their respective accounts. These differences are apparent in three respects – the preformation of knowledge, the availability of a third alternative to nature and culture, and unity and identity in social interaction. In Vygotsky’s account, a central concern is novel transformation of the learner; in Piaget’s account, it is the transformation of novel knowledge.