Garfield himself comments on these verses:

To be in samsara is to see things as they appear to deluded consciousness and to interact with them accordingly. To be in nirvana, then, is to see those things as they are—as merely empty, dependent, impermanent, and nonsubstantial, but not to be somewhere else, seeing something else. (1995: 332)

The nonduality (advaya, gnyis med) of saṃsāra and nirvāṇa has been one of the central themes explored and developed throughout all of Universal Vehicle literature (Prajñapāramitā-sūtras, Vimalakīrti-sūtra, Madhyamaka śāstric literature, etc.). It is very important to stress that in these treatises, the “nonduality” of any two things is clearly distinguished from their “unity.” Characterizations of the unity, monism, or oneness of two things invariably conflate or reduce one of those things to the other. Thurman (following Tsong Khapa’s interpretation of Nāgārjuna) has discussed these dangers at length. Coining the terms “monistic absolutist” and “existential relativist” for two possible extreme interpretations, Thurman says:

The former hold the message of the central way to be that samsara is Nirvana. The latter hold it to be that Nirvana is samsara. (1989: 150)

He then acknowledges that “[e]ither of these positions may be partially correct,” that “[e]ach has its own evidence, arguments, and advantages,” and he cites numerous Indian, Tibetan, and Western interpreters who may be said to fall into these two camps. (We might add that Queen, et al., would seem to fall into the existential relativist camp.) But then, after a lengthy defense of the merits of each of these views, he tells us that “Tsong Khapa insists that these would-be Dialecticist Centrists, or interpreters of the school, are in fact the chief antagonists (purvapaksin) of the school!” (155). After an equally lengthy discourse on Tsong Khapa’s refutation of these two extreme positions and on his Centrist solution, Thurman concludes by citing the verse above by Nāgārjuna (XXV, 19) and then emphasizing the half-truths present in each of those two extreme positions:

The absolutist is correct; there is an overriding soteric aim. There is a Nirvana, a supreme bliss. But salvation is not “mystic,” a “leap into the void” having discarded reason, and Nirvana is not a place outside the world; it is a situation that includes the world within its bliss. Samsara cannot be distinguished from it. It is in Nirvana that samsara is embraced completely. … But the relativist is also correct. “Perfection” is always correlated with “imperfection”; there is no escape from inevitable relativity. Nirvana … is just here now, and the full experiential acceptance of that is liberation, which is not a going elsewhere. But truly being “here” is not an abandonment of the Absolute, a capitulation to the mysteriousness of meaninglessness, a relative meaninglessness. It is rather an Absolute being here, a triumphal commitment to sensible duality. For part of relativity is the ideal of the Absolute. (1989: 159)

If Thurman and Tsong Khapa are correct, then from the Universal Vehicle perspective, liberation has always entailed both a transcendent, transmundane, “other-worldly” (lokottara) aspect and equally an immanent, mundane, “this-worldly” (lokiya) aspect. Both aspects exist together, nondually, without either aspect collapsing into the other.

Bringing this lofty philosophical discussion on the nature of liberation back down to Buddhist liberation movements “on the ground” (so to speak), José Cabezón tells us in Queen’s own anthology:

[T]he Buddhist social philosophy emerging out of the Tibetan liberation movement is not envisioned as a radical rethinking of traditional Buddhist philosophy. Although suggesting a new reading of Buddhist texts, a new hermeneutical lens, it does not do so at the expense of the traditional understanding of Buddhist scripture. … [I]t stresses continuity with the tradition rather than rupture. … In the Tibetan case it is not that the traditional goals of Buddhism (e.g., nirvana, the universal emancipation of all beings, and so on) are discarded in favor of action in the world. Instead, the two goals, worldly and supramundane, are seen as reinforcing each other. (1996: 311)

Moreover—and of great relevance to our discussion on Queen’s possible sources and influences—in a footnote to this passage Cabezón contrasts this nondual Mahāyāna approach with a more dualistic Theravādin one (as developed, for example, in the earlier writings of Bardwell Smith):

This [Tibetan Buddhist social theory] is in marked contrast to the theory of the development of a Buddhist social ethic that assumes the kammatic/nibbannic distinction, in which social action belongs in the kammatic, that is, “secular,” realm, and is therefore related primarily to the goal of higher rebirth, as opposed to the nibbanic aspect of the religion whose goal is emancipation from all rebirth. In the Tibetan setting, and perhaps more generally in Mahayana Buddhism, the case can convincingly be made that such a distinction is unwarranted. Social action is as much the cause of nirvana as monastic discipline is; and vice versa, typically “nibbannic” [sic] practices such as wisdom and compassion are as relevant to properly acting within the world as is the concept of karma. (1996: 317, note 57)