In 1614 Caʿfer Efendi devoted four chapters of his book on architecture to the science of surveying. Caʿfer’s text is the only extant comprehensive book written by a scholar on the relation between architecture and various forms of knowledge. His sections on surveying have attracted little scholarly attention since they were often viewed as ad hoc chapters in a biography of the chief architect Mehmed Agha. An investigation into the intersection between architecture, as represented by the architect’s cubit, the science of surveying, and jurisprudence sheds significant light on how scholars assessed the legitimacy of early modern Ottoman architecture. In this article, I examine the relationship between architectural practices, mathematical knowledge, and social practices by focusing on Caʿfer Efendi’s elaborations on the architect’s cubit, units of measure, and mensuration of areas. These links need to be understood through the cultural and scientific context in which architects and scholars collaborated. I also explore Caʿfer Efendi’s identity, which gave him the tools to discuss such intrinsic connections. When read along with court decrees, and in conjunction with the use of mathematical sciences for civic affairs, this investigation reveals how Ottoman architecture was embedded in the scientific discourses, social practices, and ethical concerns of the early seventeenth century.