This chapter focuses on the role and value of not knowing for creativity, learning and development. More specifically, it proposes a typology of states that are conducive, in different ways, for creative learning, including certain knowing, uncertain not knowing, uncertain knowing, and certain not knowing. They are discussed, in turn, in relation to four associated experiences: trust, anxiety, curiosity and wonder, respectively. Towards the end, two models are proposed that specify how and when these experiences contribute to the process of creative learning. The first is focused on macro stages, the second on micro processes. While the former starts from uncertain not knowing, goes through the interplay between uncertain knowing and certain not knowing, and ends in certain knowledge, the processual model reveals the intricate relations between these experiences in each and every instance of creative learning. The developmental and educational implications of revaluing not knowing as a generate state are discussed in the end.