Purpose of a Building

The purpose of a building is to shelter. 

On a philosophical-existential level, shelter means to enable dwelling of place. 

So, an essential purpose of a building (for the human being in this case) is to enable man to dwell on earth. 

What is “dwell”? Defining the meaning of “dwell” expands the purpose of a building into many different levels: existential, 
physical, spatial, phenomenological, semiotical, architectural, economical, functional, historical, and so on. 

In other words, imagine a specific building type in this way:- 

existential - a quiet library 
physical - a crowded concert hall 
spatial - a high ceiling church 
phenomenological - a barn at the yellow paddy field semiotical - a skyscraper that looks like a human character in Chinese (人) 
architectural - a Le Corbusier building 
economical - a township development 
functional - a factory 
historical - a monument 

Architecture is building with purpose. A building with a great purpose makes great architecture. 

As part of the research in architecture, the human lives, and culture, here is the summary of 20 things architecture can do to the world that also explains what a great building can do to the world.