In his keynote address to the 2011 Leiden conference, “Proportional Systems in the History of Architecture,” Howard Burns posited that the current study of proportional systems lacks “ground rules.” Indeed, without an agreed-upon set of conceptual and methodological assumptions on which a cohesive body of scholarship can be based, at least as a point of departure for new inquiry and debate, scholars of architectural proportion run the risk of unproductively “talk[ing] through each other,” as Thomas Kuhn describes what happens when scientists disagree—or even agree—without understanding why, thus potentially contributing to a fragmentation of collective effort. The following ten principles are proposed as a set of ground rules to help scholars talk to—rather than through—each other, and to clarify points of agreement as well as disagreement.

Principle 1: The word “proportion” signifies two unrelated and incongruent meanings

As noted in the introduction to this volume, the subject of architectural proportion today is defined by ambiguity because the very word “proportion” simultaneously signifies two conceptually unrelated meanings. Proportion technically denotes a mathematical ratio, or a relationship between ratios, and as such may be called “proportion-asratio” (or mathematical proportion). In common usage, however, it often connotes a broader meaning that in 1723 Ephraim Chambers described as “a Suitableness of parts, founded on the good Taste of the Architect,” or, an aesthetic assessment that we may call “proportion-as-beauty.” Since the first meaning is quantitative and the second qualitative, no causal relationship between them can ever be established predictably and repeatedly, as the scientific method would require. When historians use the word “proportion” without qualification, therefore, they perhaps inadvertently invite their audiences to understand it as a fusion of the concepts of ratio and beauty, and thus as an implicit assumption that certain proportional ratios contribute beauty to architecture. Consequently, in the introduction to this volume the word proportion is broken down into its incongruent component meanings, proportion-as-ratio (or mathematical proportion) and proportion-as-beauty, and it is proposed that one of these meanings hereafter be specified whenever scholars use this word, either through the use of the preceding terms or in the context of the discussion.

This distinction is particularly germane in Sigrid de Jong's analysis (Chapter 4) of the 18th-century reception of the notably stocky proportions of the Greek Doric columns of the temples at Paestum compared to the slimmer, normative Doric proportions such as those of the Parthenon (see Chapter 10).