4.10 Development is not merely clock time

Let \(\mathbb D\) be a category of developmental contexts. Its objects may record time, available actions, perceptual resolution, social setting, and the fragment of the core sketch currently exposed. An arrow \(d\to d'\) means that the learner can transport established structure from context \(d\) into the richer context \(d'\). This is not required to be a total order: motor, linguistic, spatial, and social capacities can develop along partially independent directions.

A developmental presentation is a functor

into the transcript-and-doctrine base introduced in Chapter 3. The learner selects a compatible section of the pulled-back hypothesis fibration. Thus development records both an expanding presentation and the genealogy of the hypotheses used to interpret it.