Krier thinks in terms of what I would describe as the “Yin-Yang” dyad of architectural and urban planning theory: the two complementary poles of “vernacular,” or domestic, on the one hand, and “classical,” or monumental, on the other. 

The “vernacular” manifests as buildings and private spaces, or Res Privata (also Res Economica, “economy,” deriving from oikos, “household”), and belongs to the artisan. The “classical” manifests as architecture in a grander sense and public spaces, the Res Publica, and belongs to the artist. 

These two are also clearly expressions of femininity and masculinity. But even if the Res Privata is feminine, it will include masculine elements analogous to those of public institutions (“paternal” authority), and likewise, even though the Res Publica is masculine, it will include feminine elements. We may think of how the Roman father of architectural theory, Vitruvius, distinguished between Doric masculinity and Ionic femininity. The Ionic column in a public building “gestures” towards the private; its delicate flutes and curved design relax the mind into the nurturing frame of domesticity. It is the necessary presence of the maternal in an otherwise patriarchal space, so to speak (the white dot in the black “Yin” of the Yin-Yang circle).

In this context, we may also suggest that each sphere contains two kinds of spaces, one more extroverted and one more introverted: The private sphere includes economically active assets like shops and storehouses as well as private homes, and the public sphere is composed of government houses, like the town hall, but also walkways, parks, and so on.

....