According to Nagarjuna Pratitya Samutpada is Unreal (Sangharakshita)

Nagarjuna does not shrink from the conclusion that if causation is unreal the pratitya samutpada is also unreal. In fact, he insists upon it, for according to him only by recognizing the merely relative validity of this teaching can its true import be preserved. The Hinayanists had interpreted the Buddha's 'conditioned co-production' as the temporal sequence and spatial juxtaposition of ultimately real entities between which real causal relations obtained. Such an interpretation amounted to a repudiation of the fundamental Buddhist doctrine, of which, paradoxically, the pratitya samutpada was intended to be an expanded statement, the doctrine of the essencelessness and unsubstantiality of all phenomena whatsoever. In the interests of the correct intepretation of the Dharma, Nagarjuna showed that the pratitya samutpada taught not a real causal relation between entities but their mutual dependence, hence their lack of independent selfhood, and that it therefore consisted of a sequence and juxtaposition not of realities, as the Hinayanists thought, but only of appearances. Consisting as it did entirely of appearances the pratitya samutpada was itself merely an appearance; it was unreal; it could not be said to exist, or not to exist, or both or neither. Consequently it was to be equated with shunyata [emptiness].

In this way did the dialectic of Nagarjuna, by exposing the contradictions inherent in the Buddhist doctrines themselves when taken literally, serve as a reminder of the supremely important fact that these doctrines, constituting the conceptual formulations of Wisdom, possessed not absolute but only relative validity, and were not ends in themselves but only means to an end. That end was of course Enlightenment. By shattering the hard shell of literalism in which Buddhism was then imprisoned, Nagarjuna not only saved it from suffocation and probably death but also gave it room for future development. Recognition of the relativity of the means to a certain end leads, sooner or later, to the recognition of the possibility of there being a plurality of means. As far as the various methods conducive to Enlightenment are concerned, however, since they must pertain either to Morality, or to Meditation, or to Wisdom, all are included archetypically in the Means to Enlightenment proclaimed by the Buddha.

One of the principal charges brought by the Mahayanists against the Hinayanists was that the latter conceived Nirvana almost exclusively in terms of negation. They defined it either as the cessations of pain or of the five skandhas or of the pratitya samutpada or some either supposedly positive entity or collection of entities: the Absolute was defined as privation of the contingent. Since the world, in the sense of the total aggregate of causally associated dharmas, was believed to be real, the cessation of the world was a real cessation therefore valid in the absolute sense. One of the results of Nagarjuna's dialectic was to render such a position quite untenable. Pratitya samutpada being ultimately unreal its cessation too was unreal; Nirvana could not, strictly speaking, be defined in terms of cessation. In fact it could not be defined at all. (from A Survey of Buddhism, by Sangharakshita [Dennis P.E. Lingwood], 1957, 1980, London 1987)