Echoes of Emptiness
"Form is no other than Emptiness and Emptiness is none other than Form." ~ Heart Sutra
People love to spout this quote without having the slightest inkling about Madhyamika Buddhism.
Emptiness is the highest truth in Madhyamika (middle-way) Buddhism but it doesn't mean nothingness as nihilists think; it means Interdependence.
Emptiness and Interdependence have many definitions. Basically, nothing can be said to arise alone or exist solely from its own side. As for eternal essences? None can be observed anywhere, at any time!
Basic example of Emptiness: Sight does not occur without something to see, just as the existence of perceivable objects is affirmed when they are seen. Neither comes first since they arise mutually.
Madhyamika points to a conciliatory middle-path between opposite extremes that are normally thought of as mutually exclusive. Polarized thinking is dualistic and hence mistaken.
Many Buddhists consider a proper understanding of Sunyata (Void / Emptiness) to be the highest realization attainable, equivalent to enlightenment itself.
Emptiness is known as Mayavadi (Voidist) philosophy by various Hindu schools of thought that reject it as Atheism. They need a personal deity to latch onto and so cannot intuit the merits of Sunyata.
This is due in part to a purely intellectual understanding of the concept, which is not enough. Without regular meditative practice, Sunyata cannot actually be experienced and so fails as mere theory.
Contrary to common belief, Buddhist Sutras on Emptiness do not assert that the universe is an illusion. That is another type of dualism reconciled by the doctrine of Two Truths.
These Two Truths are flip-sides of a coin. On one hand, material manifestation is regarded as 'provisional' or constantly shifting. However, this doesn't mean that laws of physics don't apply.
On the other hand, ultimately reality is transcendental to the first yet includes and encompasses it. Form is Emptiness and Emptiness is Form, remember? Neither more real nor important.
Indeed, Arya Nagarjuna similarly wrote "There is not the slightest difference between Samsara and Nirvana." Cyclic existence and Emptiness ARE each other!
Those who think that the universe is an illusion are in the same boat as those that view God as being outside of creation and not within it.
It's not our universe that is illusory but the scummy perceptive lenses that we view it through. Physical reality though fluctuating is quite sacred.
No doubt perception molds reality to a great extent but the fundamental matter / energy thereby molded is very real or even better said: Ethereal.
From holy visions to hallowed sounds - the whole gammut of psychic-sensory experiences - these are all Echoes inside Emptiness!