One issue turns again on the individualistic interpretation that is usually given to nirvana. That is, in the Zen tradition where nirvana is taken to represent a kind of existential awakening to the nonsubstantiality of the mundane world there is a definite focus upon the individual's experience that some have claimed is asocial by nature. The goal of nirvana seems to be a personal goal, involving an existential awareness of the real nature of things and a release from one's own karmic chains. Therefore, by focusing on the experience of nirvana as such, traditional conceptions of Zen have made it difficult to see how such personal transformation might possibly translate into any kind of substantial social transformation.

Second, while the Zen notion of nirvana, unlike the Theravāda one, does not take nirvana to be a literal plane of existence separate from the mundane world of saṃsāra but instead sees nirvana in terms of an existential realization within this one world of the real nature of things, it does still seem to suggest that the quest for nirvana involves some kind of an abandonment of the world of saṃsāra. Indeed, it would seem that any focus on the social world around one would further entangle the Zen practitioner in the kind of distinctions and attachments that he or she is seeking to overcome. The kind of existential realization that Zen offers in its notion of nirvana appears to remove its adepts from any possible involvement in the social sphere precisely because real involvement in those concerns presupposes making the kind of commitments and distinctions that Zen seeks to overcome as its ultimate goal. The social world, by its very nature, belongs to the world of saṃsāra and it is thus seems that if nirvana is the goal of Buddhist life, and nirvana involves an overcoming of the distinctions within that world, then it would follow that the social world with all of its distinctions and involvements is ultimately beyond the sphere of Buddhist conceptualization. Social problems appear to be problems that are necessarily rooted in the contingent fleeting world of samsāra and thus appear to be something the Buddhist must ultimately leave behind.

Closely related to the concept of nirvana is another central Buddhist notion, that of śūnyatā or absolute emptiness. Indeed, they are often taken as equivalent. However, for our purposes it might be useful to distinguish the two terms in the following manner. We might say that if nirvana represents the existential awakening to the true nature of things, then śūnyatā designates the ultimate ontological reality that one is awakened to. As Masao Abe states it:

the ultimate reality for Buddhism is neither Being nor God, but Sunyata. Sunyata literally means "emptiness" or "voideness" and can imply "absolute nothingness."(20)

Earlier, we mentioned that Buddhists take the universe to consist ultimately in an ongoing process of generation and degeneration in which nothing is absolute. Śūnyatā thus represents the ultimate unsubstantiality of all things according to Buddhism; the Buddhist recognition that the self and the objects of perception are empty of self-existence. Christopher Ives encapsulates this view of śūnyatā nicely in remarking that "as a logical and metaphysical term, śūnyatā indicates both the lack of any independent essence or self in things and the interrelational dynamism that constitutes things."(21) There are really then two aspects concerning the ultimate nature of things that the notion of śūnyatā takes into account. First, there is the Buddhist idea that nothing exists independently or subsists on its own, rather everything is what it is in virtue of its causal interrelationships with other things. Here we have the Buddhist notion of co-dependent origination. Second, there is the idea that nothing in these networks of things is stable, as everything is subject to the process of generation and decay. Abe summarizes the view of ontological reality that śūnyatā is meant to capture in saying that "the universe is not the creation of God, but fundamentally is a network of causal relationships among innumerable things which are co-arising and co-ceasing."(22) Śūnyatā as absolute emptiness thus signifies both this process of emptying (by which all entities are ceaselessly transformed) and the lack of any stable, self-subsistent entities or principles that we might take as ontologically basic.

As to be expected, the doctrine of śūnyatā has also come under critical scrutiny in its encounter with other modes of thought. In maintaining that ultimately all conditioned reality is of the same ontological status, the Zen notion of śūnyatā seems to erode the possibility of distinguishing between various contingent social arrays. It seems that Zen can provide no criteria for privileging one contingent state of affairs over another, since they are all ontologically equivalent. The very attempt to establish one contingent assemblage in preference to another would seem to involve some substantial criteria.