This study seeks to disentangle claims of institutional and organizational learning theories and to shed light on the impact of Knightian (environmental) uncertainty in discovery opportunities. This article suggests, and finds empirical support for, the concept that emerging professional service industries retain high levels of causal ambiguity. High uncertainty interferes with institutional theory's claim of mortality reduction through isomorphism, but leads to superstitious learning, increasing organizational mortality hazard. Education and experience of entrepreneurs help them identify discovery (exogenous) opportunities for entrepreneurial rents, while high (but untheorized) levels of uncertainty interfere in their ability to successfully exploit these same opportunities. Copyright © 2012 Strategic Management Society.