This paper provides a set-theoretic model of knowledge and unawareness. A new property called Awareness Leads to … Knowledge shows that unawareness of theorems not only constrains an agent's knowledge, but also, can impair his reasoning about … what other agents know. For example, in contrast to Li (2009), Heifetz et al. (2006) and the standard model of knowledge …

if common knowledge is assumed (as in the settings of Aumann [1976] and Milgrom and Stokey [1982]), unawareness cannot … generate speculation. This is not true, however, in settings where no common knowledge is assumed, such as speculation in …