Aesthetics is the branch of philosophy which studies concepts of beauty. Theories of beauty vary over time and reflect preferences which, when widely agreed upon are called taste, and which also reflect more basic currents of thought in societies. "Form follows function“Louis Sullivan implied was that architecture—or in his phrase, "form,"—is a natural consequence of meeting functional requirements.
The designer is responsible for integrating the design elements of the building and will make decisions and selections which support this integration.
The point is that while it is appealing to reduce design decision making to a brief set of rules or axioms, nearly all designers agree it is impossible to do so. It is also essential to be aware of current social, economic, and technological developments which continue to change what is possible in the realm of aesthetics.