The association of metaphysics with nature is a common one. In this excerpt, Dan Brown describes a pagan sexual practice, which is called Hieros Gamos. I have numbered the sentences of the excerpt to make it easier to follow the explanation:
[1] Hieros Gamos [ritual sex] was a spiritual act. [2] Historically, intercourse was the act through which male and female experienced God. [3] The ancients believed that the male was spiritually incomplete until he had carnal knowledge of the sacred feminine. [4] Physical union with the female remained the sole means through which man could become spiritually complete [...] [5] By communing with woman […] man could achieve a climactic instant when his mind went totally blank and he could see God. […] [6] Physiologically speaking, the male climax was accompanied by a split second entirely devoid of thought. [7] A brief mental vacuum. [8] A moment of clarity during which God could be glimpsed" (ch. 74). |
This excerpt describes sexuality, i.e. nature, but it does so by assigning to it metaphysical attributes. Thus, the sexual practice is "a spiritual act" (1) through which you can "experience[...] God" (2), and physical union and the lack of it have to do with "spiritual" completeness and incompleteness (3 & 4); the sexual climax is also a spiritual one, for it makes the vision of God possible (5 & 8), and is curiously accompanied by lack of thought (6 & 7), which makes sense if we take into account that one of the most typical attributes of nature is that it is opposed to the higher-order functions in human beings, such as thought.