How architectural rules make room for creativity: an ontology-driven analysis Stefano BORGO a,1 and Maria Rosaria STUFANO MELONE b a Laboratory for Applied Ontology, ISTC-CNR, Trento, Italy b Politecnico di Bari, Bari, Italy Abstract. Architecture is said to be a science and an art as it is about construc- tion and communication, form and matter, rule and novelty. The paper begins by looking at how architecture has been discussed in the literature from the words of both architects and theoreticians. This leads to identify a set of architecture’s core elements, in particular regarding the meaning of rules, and a notion of meta-rule about composition choices in architecture. It follows that the act of creativity has a way to manifest itself into this domain via the described interplay between rules and meta-rules. The main contributions of this paper are an ontology-driven discussion of archi- tecture from the given perspective, and an initial proposal on how to isolate and un- derstand architectural rules. The goal is to show that there is a way to model these elements and their interactions, that is suitable for future integrations into formal systems. This, we believe, can turn architectural creativity into a subject for formal representation and exploitation. Keywords. Architecture, Rule, Creativity, Representation, Ontology 1. Introduction Architecture embraces and integrates several domains: design, civil engineering, material science, social science, aesthetics etc. making it an inherently interdisciplinary domain along many others like engineering, economics and medicine, just to name a few. Yet, architecture is interdisciplinary in a stronger sense as it is, has been and aims to be at the same time a science and an art [7]. This latter claim may be understood in different ways but one thing is clear: it puts doubts on whether formal systems can practically and effectively deal with architecture. The creation process in architecture starts with the request of the design of a build- ing or the (re-)organization of an area, and ends with the implementation of the chosen solution. Overall it is a complicated process and we focus on the first part only, namely, the design process. This restriction in focus highlights the goal of the paper, that is, to characterize two core factors in the architect’s practice: architectural rules and creativity. Generally speaking, we aim to shed some light on the relationship and integration of these elements, and on their connection to architectural types, even though we will not tackle explicitly the latter notion in this paper. Also, we do not deal at this stage with the 1 Corresponding Author: Stefano Borgo, LOA ISTC-CNR, Trento, Italy; E-mail: stefano.borgo@cnr.it