Our initial focus was on development in general, with a gradual narrowing to the nature of human development. From now on we will concentrate on conceptual development. The present chapter begins with an elaboration of the idea, introduced in chapter 1, of foundational analysis. Next we distinguish, and sketch the relations between, what we call the three levels of meaning: expressions, reasons, and foundations. Then we return to the developmental context, to ask how, and to what extent, such foundations might be said to develop, using that term in the sense defined in chapter 2.