 All the various characteristics and relations of things are here to be apprehended, as we’ve said, as “dwelling together in (or as) a single moment of mentation” (同居一念). So far this resembles a perhaps familiar “phenomenological reduction” of all experience to their manner of appearing to the subject. But it is not “the subject” as such that is at issue in this Buddhist context. Rather, the traditional Buddhist stress on momentariness is to be remembered: it is a reduction of all objects to subjective experience, but subjective experience itself is understood as a temporal series of putatively discrete instantaneous mental events. So we are aiming at a phenomenological reduction of all moments of experience to a single present moment. On the theoretical level, however, Mahāyāna philosophy had already long exploded the viability of taking this pre-Mahāyāna Buddhist concept of momentary experience literally as ultimate truth, as if these moments were actual entities that were simply “different” from one another, showing instead that these moments stipulated by earlier Buddhist philosophers are “empty” of self-nature: no consistent metaphysical unpacking of this idea of discrete moments is possible. This refutation certainly was always understood to mean that in ultimate truth there could be no such entities as moments with predicates of “same” or “different” legitimately applied to them. For not being actual entities at all, and thus certainly not different, they also could not be said to be the same, nor could any other predicates be validly attached to them; what does not exist cannot have any predicates. But where does that leave us? It might be taken simply as a call to free ourselves from all conceptualization, all metaphysical views, and to deal instead with reality just as it is appears to us in our practical everyday experience. But in practical terms, this “just as it is appears” too often reverts to seeing experienced time in the same old way, or even in the pre-Buddhist way: not as instantaneous moments which are simply and absolutely different from one another, to be sure, but reified as discrete clumps of experienced time which are simply and absolutely different from one another, a past experience that is an entirely different entity from the present experience, a present that is different from the future. Unfortunately, this is precisely the presupposition that underwrites all of our delusive desires and attachments: the idea that past experience and the future experience are mutually exclusive, structured just like metaphysically constituted “things” in that they have consistent self-identities, such that one can move from suffering experience to non-suffering experience in a non-ambiguous way—another view demolished by the very same Mahāyāna philosophy of Emptiness. This preservation of the conventional is of course essential to Buddhist practice, and for some Buddhist schools the impossibility of giving any consistent metaphysical explanation of this conventional experience of progressive time is therefore a feature rather than a bug. It safeguards the necessary conventional apprehension of progressive time and the possible achievement of truly continent and disparate states at different times that must be assumed for the practice of the Buddhist path, and blocks any temptation for an alternative model of temporality, which on this view would be just be one more metaphysical distraction and distortion of the practical soteriological realities involved. The Tiantai position is also strenuously committed to preserving the viability of this conventional model of progressive time for purposes of Buddhist practice, but only in closest tandem with the most robust possible understanding of the contrary side of the Mahāyāna theoretical apparatus: the non-difference of samsāra and nirvāna, of affliction and wisdom, of suffering and the end of suffering. The practice focusing on “all dwelling together as a single moment” is designed to bring these two sides of Buddhist philosophy together in practice, as they are brought together in theory in the doctrine of the Three Truths. Phenomenologically as well as theoretically, this means seeing that both the early Buddhist view of “momentariness” (the idea that all experience takes place only in the instantaneous “now”) and the alleged alternatives to this, for example the perhaps more commonsensical “specious present” of Jamesian psychology (i.e., that there are no experiences that can take place in an instantaneous moment, because mental reality always comes with an experienced fringe of past and future, a short span of discernible and certainly finite duration to be strummed through), are seen equally as one-sided distortions, because both are equally true. Both momentariness and duration are incoherent explanations of experience, although both are unavoidable: they are locally coherent but globally incoherent. The first is impossible because experience requires contrast, and contrast requires a simultaneously present multiplicity of moments to strum through. The latter merely pushes the problem back one step, positing a new slightly larger oneness, and stipulating that its boundaries are vague without trying to work out how a boundary that is vague can still function as a real boundary, thus setting up an infinite regress, abandoning the possibility of determining precisely where a single experience begins or ends but continuing to treat it practically as finite, i.e., as mutually exclusive with other experiences (as is the premise of all ordinary sense of identity and motivated action); the component parts of the specious present, in spite of their constituent bleed-over into one another, remain trackable as qualitatively distinct parts, and the specious present as a whole continues to function as an unproblematically distinct though extended unit, a particular specious present that is different from all the other specious presents experienced by oneself and others at other times and places. The former stresses the “one,” the latter stresses the “many,” but in reality experience is neither one nor many, both one and many; neither same nor different, both same and different. All experience is instantaneous, and yet all experience extends beyond itself into past and future—and this now applies as much to a specious present as to an instantaneous present. Rather than seeing one of these views as true and the other as a pernicious distortion (for example, because the surreptitious application of objective or spatial categories is distorting what is actually observed phenomenologically), both are admitted as precise and unavoidable aspects of what it is for an experience to be an experience. The alternative between them is thus viewed as a case of aspect-change, as in the Wittgensteinian duck-rabbit; we can switch from seeing the moment of experience as instantaneous or as extended and enduring to make sense of its manifold content, but normally cannot see both, or grasp the necessary connection between these mutually exclusive ways of apprehending it. Tiantai meditation is aimed at experiencing both of these aspects at once, a flat picture that is also three-dimensional, a flash of an instant which is also extended without any definite limits, for their necessary though paradoxical relationship reveals the true nature of all the contents of experience as neither-same-nor-different.