Breathing fire metaphor
Stephen Hawking suggests that mathematical theories are all well and good, but it is the questions behind these theories that make the pursuit of science interesting. He states that "the usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?. He then uses a metaphor to illustrate this idea, saying "What is it that breathes fire into the equations and makes a universe for them to describe?" Here, the metaphor of breathing fire into something suggests a sense of passion, interest, and intrigue.
"The dawn of civilization"
Hawking uses the phrase "the dawn of civilization," which is a metaphor for the beginning of humanity, using the image of the start of a new day.
The child
Hawking writes that he is a "child who has never grown up," saying that "I still keep asking these 'how' and 'why' questions." Here, he metaphorically compares himself to a child, in order to emphasize his sense of curiosity and passion.
