How Do Children Learn What They Cannot Detect? A Commentary on Giunta and Pouscoulous

Giunta and Pouscoulous offer a careful and detailed developmental timeline for presuppositions, showing that children understand and appropriately use many presuppositional expressions by age 4. My aim in this commentary is to discuss an underappreciated problem: how did the 4-year-old figure out that the presuppositional word encodes a presupposition in the first place? The trouble is that the properties that define the category of presuppositions—their backgroundedness, uninformativeness, and nonsalience—render them invisible on the usual information channels for word learning. The usual strategies therefore offer little basis for positing a presuppositional word meaning over a simpler alternative without one. Yet, children do learn these meanings; we need to understand how.