The essence of architecture is not about aesthetics; it is about space and how we, as individuals react and relate to space. Aesthetics suggests a visual experience only, while a spatial experience has the potential to stimulate all our senses and thereby encourage individual thought. Like all of the fine arts the essence of architecture is communication. This is fundamental.
The painter paints his soul on canvas, the writer or poet uses words on a page – the paint and print themselves, although necessary to convey the message, are not the essence of the art form.
The same principle applies to architecture where the space that the building form creates, not the form itself, is the essence of architecture and is how the architect communicates to himself, and therefore to others. This illustrates the artist communicating himself to himself, to ‘see’ and understand himself. If others find meaning in it, find that it stimulates them into their own thought, not the artists thought, then I believe we have defined ‘art’ and therefore architecture.