the presence of the invisible within the visible

In Greek philosophy, …the highest kind of knowledge, and therefore the highest moment of earthly life, …connected the visible with the invisible. [This] was noetic: the unencumbered exercise of that highest faculty of alertness and heedfulness and comprehension for which they reserved the name, “nous,” a noun that we can render variously as intellectual intuition, immediate apprehension, mans or mind, or in Jacob Klein’s plainer (and hence, more incisive) rendering, prepared openness, attentive consciousness. …It is a heedful awareness that is “open” to the presence of the invisible within the visible, of a kind of divinity within nature. [This] connection of nous with transcendence, spirituality, and above all mysticism is hard to miss for anyone not already dedicated to the modern project of reading the philosophers of Greek antiquity as Enlightenment phflosophes.

The Noetics of Nature: Environmental Philosophy and the Holy Beauty of the Visible by Bruce Foltz.