Huayan presents reality as a single, integrated Dharma realm in which all things are mutually interdependent and interpenetrating. Ultimate principle (li) and concrete phenomena (shi) are distinguished conceptually, yet are understood to be non-dual: each particular thing fully expresses the universal principle, and that principle is never apart from the myriad things. What appears as a world of separate entities is, from this perspective, a seamless web where nothing exists in isolation and everything conditions and is conditioned by everything else. The totality of existence forms one unified cosmic body, in which unity does not cancel difference but is realized precisely through it.

This vision is articulated through the teaching of the fourfold Dharma realm. There is the realm of principle, in which all things share the same empty, ultimate nature, and the realm of phenomena, in which each thing appears as distinct and particular. Huayan then speaks of the non-obstruction between principle and phenomena, meaning that emptiness does not negate the world but allows every phenomenon to manifest fully as an expression of ultimate reality. Finally, there is the non-obstruction among phenomena themselves, where each phenomenon is said to interpenetrate all others without hindrance, so that “one is in all, and all is in one.”

The famous image of Indra’s Net gives a vivid metaphor for this understanding. Reality is likened to an infinite net with a jewel at every node; each jewel reflects every other jewel, and within each reflection all the others are likewise contained, ad infinitum. In this way, every phenomenon both contains and reflects the entire universe, while at the same time being itself only through its relations to all others. Changing one jewel changes the reflections in all, illustrating that each event, being, or moment is inseparable from the whole network of causes and conditions.

Underlying this vision is the doctrine of emptiness: all phenomena lack independent self-nature and do not possess a fixed, separate essence. Their existence is dynamic and relational, arising only through mutual dependence, and this very emptiness is what makes complete interpenetration possible. Reality, then, is not a collection of solid, self-contained units, but a holographic and dynamic display of interconnectedness where each part mirrors the whole. Awakening, in this tradition, is the direct realization that in any single phenomenon the entirety of the Dharma realm is present, and that the path does not lie in escaping the world of phenomena but in seeing their true, interdependent nature.