What is the theme in A Brief History of Time by Stephen Hawking?

The thirst for knowledge is closely related to the discomfort of uncertainty. Stephen Hawking has a natural thirst for knowledge about the nature of the universe. He seems less interested in the nature of God, or thinks that nature is simply irrelevant when it comes to physics. Yet he mentions God regularly, most notably while addressing possibilities which go against Roman Catholic Church doctrine. Fear of the Church does not extinguish his thirst for knowledge, nor does it stop Galileo from laying the foundation of modern physics. The author feels a strong association with Galileo, possibly hinting at some sort of spiritual connection that physics can never describe.