Structural Architecture defines the outcome of a building to the world, so does Software Architecture to an application. It has a role from the very early stages of conception to the end of the development cycle.
It is like a painting that comes to life from a blank sheet of canvas. It begins with a concept on an empty page. Iterative changes and collaboration with other experts gives it an outline. Technological advances provides the opportunity for exploration while the same technology can limit the boundaries. The outline then evolves to well defined structure with tangible components. All this requires the skills of art, science and engineering.
Art is rather abstract and fluid. Such a mindset is critical in the early stages of defining a software architecture.
Science is often experimental and forward looking. These traits are essential to explore new frontiers in technology.
Engineering is a disciplined approach to adapting proven concepts. It is necessary to guarantee practical success.