His "Theology in the Flesh: How Embodiment and Culture Shape the Way We Think about Truth, Morality, and God" is the first book to apply the field of cognitive linguistics to theology. According to cognitive linguistics, the specific types of bodies humans have shape how we interact with and understand our world. We have concepts such as up/down and in/out because we have bodies that can experience these sorts of things. Embodied experience also gives rise much of our metaphorical thinking. For instance, we know what it is like to go on a journey in which we experience getting to a destination together and perhaps overcoming obstacles on the way. Many, but not all, languages use the experience physical journeys as the framework in which to understand the experience of love. We say, "Our relationship has come a long way together" and "We have overcome many bumps in the road." We reason about our love relationship in terms of a journey. Yet, in English, we also conceive of love in terms of strong physical forces ("He's blown away by love"), magnetism ("She is attracted to him"), and even insanity ("He is crazy about her"). That means that metaphors can be cognitive and not merely rhetorical. We actually think with metaphors.