““Two hundred years later, Piaget reformulated this question from a more psychological perspective. It is no coincidence that he referred to Kant as “the father of us all” (Piaget, 1965/1971, p. 220). Several researchers (e.g., Lourenço & Machado, 1996; Smith, 1993) consider the question about the origin of necessary truth one of the central issues of Piagetian epistemology. Indeed, Piaget's investigations into object permanence, conservation of quantities, and operational knowledge – concepts that form the bedrock of mathematics and natural sciences – are directly related to the Kantian question.””
