The Lens of Religion
This book contrasts two points of view, or rather, two types of point of view: religious faith and reason (or science). The lens of religion is the imagery used by folks who explain their motives in religious terms. They look into the universe and see a religious narrative, an experience of reality that makes God an obvious hypothesis. Although history has wandered more toward reason than religion in these most recent eras, the book notices that the religious point of view is the default point of view for all people across the planet.
The Lens of Reason
Therefore, the lens of reason might be called the skeptical approach to reality. After thousands of years of unquestioned religious belief, some people gradually began constructing this new point of view, one that takes nothing for granted except what is necessary for the construction of the scientific process. The scientific lens can be used for technological progress, and it can be applied, as Frazer does, backward onto the religious assumptions of the past.
Primal Humanity
Primitive human cultures are absolutely relevant in this book, because the beliefs of emerging people groups help to paint a picture of the human experience from the ground up, starting at animal instinct and moving toward the constructs that guide human existence today, like language, community, law, and art. The exotic and often intimidating cultures from ancient times can be contrasted with present day assumptions with insightful results.
Art and Experience
Frazer mentions the namesake of his book, Golden Bough, the painting by J.M.W. Turner. He discusses art as a byproduct of the human experience, analyzing the way humans have always sought to encode the abstract, ineffable meaning of their life into something artist that outlives them. He analyzes this process through both the religious lens and the scientific lens and analyzes his own personal relationship to the art he loves most.