Critical analyses of the audit profession have become more common in recent years. Many of these analyses focus on the entire audit profession in developing their criticisms and concerns. In this paper, the scope of analysis is narrowed to examine in depth the auditing profession's use of the concepts of reasonable assurance and materiality in audit performance and audit communications. Reasonable assurance and materiality are the terms that auditors use to describe the scope of their responsibility to the public. Similarly, reasonable assurance and materiality are the key determinants of audit effort. An overview of official guidance, practitioner reports, and academic research reveals that these two key concepts are not well specified nor are they consistently applied in audit practice. These findings are evaluated from two competing perspectives on professions – the traditional, functionalist perspective and the critical theorists' perspective. Evaluation from the latter perspective leads to a conclusion that the profession's use of these key terms to guide practice and communication leaves the profession open to charges of mystification and unjustified paternalism.