Nagarjuna's Seventy Stanzas: 2 - 4 "All phenomena must have either self-existence or non-self-existence.
All phenomena which are the subject of this treatise are similar to nirvana because all phenomena are devoid of inherent existence.
What is the reason for this? It is because the inherent existence of all phenomena is not to be found in causes, conditions, aggregations or individualities. Thus all phenomena are devoid of inherent existence and are empty."