A map, in other words, is an arrangement of symbols into a system of meaning — and we use maps because we understand the language of signs that undergirds them. If the mapping of space was a human invention, she explained, one could also invent a means of mapping time. 

Mental models describe the way the world works. They shape how we think, how we understand, and how we form beliefs.

It was a map of human meaning itself, uncompromising in both the scope of its reach and the veracity of its contents.