Sunyata, then, carries and permeates all phenomena and makes their development possible. Sunyata is often equated with the absolute in Mahayana, since it is without duality and beyond empirical forms. In quantum physics, ultimate reality is equated with formless energy at the core of the atom. This energy (of physics) or sunyata (of Mahayana) is not a state of mere nothingness but is the very source of all life and the essence of all forms.
Another helpful way to undertand sunyata is through the Zen term of "nowness," sometimes used interchangeably with "momentariness." In the absence of a permanent, abiding substance anywhere, there is only the nowness of things: ephermeral, transitory, momentary. In traditional Buddhist literature, the "nowness" of things is described as tathata or "suchness." The concept of tathata was first formulated by Asvaghosha, another great Buddhist thinker who probably lived a hundred years before Nagarjuna, and influenced him greatly. In Asvaghosha's formulation, when the futility of all conceptual thinking is recognized, reality is experienced as pure "suchness." What is realized in suchness is the existence of form-as-itself (the treeness of the tree, for instance), but that realization is suffused in intuitive wisdom (prajna) so that the ultimate reality of the form is seen as momentary and essentially devoid (sunya) of any lasting substance. Masao Abe, among others, insists that "Emptiness is Suchness."
Lama Angarika Govinda uses the word "transparency" to come to a fuller understanding of sunyata:
If sunyata hints at the nonsubstantiality of the world and the interrelationship of all beings and things, then there can be no better word to describe its meaning than transparency. This word avoids the pitfalls of a pure negation and replaces the concepts of substance, resistance, impenetrability, limitation, and materiality with something that can be experienced and is closely related to the concepts of space and light.
He goes on to elaborate,
Far from being the expression of a nihilistic
philosophy which denies all reality, it (sunyata)
is the logical consequence of the anatman
(non-self) doctrine of nonsubstantiality. Sunyata
is the emptiness of all conceptual designations
and at the same time the recognition of a higher,
incommensurable and indefinable reality, which can
be experienced only in the state of perfect
enlightenment. While we are able to come to an
understanding of relativity by way of reasoning,
the experience of universality and completeness
can be attained only when all conceptual thought,
all word-thinking, has come to rest. The
realization of the teachings of the
Prajna-paramita Sutra can come about only on the path of meditative practice
(yogacara), through a
transformation of our consciousness. Meditation in
this sense is, therefore, no more a search after intellectual solutions or an
analysis of worldly phenomena with worldly means--which
be moving around in circles--but a breaking out
from this circle, an abandoning of our
thought-habits in order to "reach the other shore"