Nagarjuna and a cup of coffee
(for a primer on the doctrine of emptiness read my last blog post here)
"we do not explain
without accepting conventions" —Nargajuna, Rebuttal of Objections
Nargajunas teachings emphasize the empty nature of phenomena throughout his works. Much in the same way that dreams arise from no source and have no actual content yet are experienced as reality, the phenomenal world is taught to be an illusion whose true nature is dependent origination. This means that a coffee cup cannot be viewed apart from the endless chain of conditions that brought it into existence. The clay it was shaped from was dug up from the ground that was once an ancient seabed made of sediment of particles of even more ancient volcanoes. The hands that shaped it arrived at that moment from an infinite series of beings who survived since the beginning of life on earth, which was preceded by the 4 billion years of cosmic evolution that created atmospheric conditions on earth that allow water molecules to survive. All apparent phenomena are an atemporal web of (illusory) existence and cannot be categorically isolated from the causes that created them. And if everything is one thing, there is no duality, and everything is also nothing; thus it is beyond our relative conceptions of existing, or not existing.
Despite this, we still have the experience of holding a coffee cup. This is the same experience we might have holding a coffee cup in a dream, in fact there ultimately is no difference between the two. Still, we have words to describe them both. Words are also a thread of dependent origination, and equally as unreal as any other phenomena. When explaining the world in any capacity, it is necessary to describe things in relative, conventional terms, because that is one of the few ways we have to transmit the answers of how to see beyond the illusion. It is also possible to realize this truth directly with no instruction or need for relative truths; we use the training wheels of explanation to help arrive there. This is why phenomena is taught to be empty, it has the appearance to us of existing independently when in fact there is no such thing.