For one thing it was emphasized that Piaget studied cognitive development. Although the relevant contrast set was often left a bit vague (cognition versus what? Behavior? Conation? Emotion? Nonrepresentational thought?) it was made relatively clear to us by our teachers that the fact that Piaget studied cognitive development meant at least these two things: (a) that he studied the mind of the child the way one might study the mind of an ideal scientist or a logician, and (b) that from a Piagetian perspective growth or development had something to do with endorsing true propositions.