Ackowledge the mistake.
Referring to Op question.
It is difficult to assume a concept in Theravada about Ultimate reality or Final Reality. What we can find is the Doctrine of Paticcasamupada and Doctrine of Kamma and Vipaka.
Theravada promote the expirience not existence.
See this Bhikkhu Bodhi quote:
"When we investigate our experience exactly as it presents itself, we find that it is permeated by a number of critically important dualities with profound implications for the spiritual quest. The Buddha's teaching, as recorded in the Pali Suttas, fixes our attention unflinchingly upon these dualities and treats their acknowledgment as the indispensable basis for any honest search for liberating wisdom. It is precisely these antitheses — of good and evil, suffering and happiness, wisdom and ignorance — that make the quest for enlightenment and deliverance such a vitally crucial concern.
At the peak of the pairs of opposites stands the duality of the conditioned and the Unconditioned: samsara as the round of repeated birth and death wherein all is impermanent, subject to change, and liable to suffering, and Nibbana as the state of final deliverance, the unborn, ageless, and deathless. Although Nibbana, even in the early texts, is definitely cast as an ultimate reality and not merely as an ethical or psychological state, there is not the least insinuation that this reality is metaphysically indistinguishable at some profound level from its manifest opposite, samsara. To the contrary, the Buddha's repeated lesson is that samsara is the realm of suffering governed by greed, hatred, and delusion, wherein we have shed tears greater than the waters of the ocean, while Nibbana is irreversible release from samsara, to be attained by demolishing greed, hatred, and delusion, and by relinquishing all conditioned existence.
Thus the Theravada makes the antithesis of samsara and Nibbana the starting point of the entire quest for deliverance. Even more, it treats this antithesis as determinative of the final goal, which is precisely the transcendence of samsara and the attainment of liberation in Nibbana. Where Theravada differs significantly from the Mahayana schools, which also start with the duality of samsara and Nirvana, is in its refusal to regard this polarity as a mere preparatory lesson tailored for those with blunt faculties, to be eventually superseded by some higher realization of non-duality. From the standpoint of the Pali Suttas, even for the Buddha and the arahants suffering and its cessation, samsara and Nibbana, remain distinct.
Where I think the teaching of the Buddha, as preserved in the Theravada tradition, surpasses all other attempts to resolve the spiritual dilemmas of humanity is in its persistent refusal to sacrifice actuality for unity. The Buddha's Dhamma does not point us toward an all-embracing absolute in which the tensions of daily existence dissolve in metaphysical oneness or inscrutable emptiness. It points us, rather, toward actuality as the final sphere of comprehension, toward things as they really are (yathabhuta). Above all, it points us toward the Four Noble Truths of suffering, its origin, its cessation, and the way to its cessation as the liberating proclamation of things as they really are. These four truths, the Buddha declares, are noble truths, and what makes them noble truths is precisely that they are actual, undeviating, invariable (tatha, avitatha, anannatha). It is the failure to face the actuality of these truths that has caused us to wander for so long through the long course of samsara. It is by penetrating these truths exactly as they are that one can reach the true consummation of the spiritual quest: making an end to suffering"
There is an interesting quote from Karnel Wainer, in his Book Mysticism and Indian Spiritualty:
"Experience is ... the path most elaborated in early Buddhism. The doctrine on the other hand was kept low. The Buddha avoided doctrinal formulations concerning the final reality as much as possible in order to prevent his followers from resting content with minor achievements on the path in which the absence of the final experience could be substituted by conceptual understanding of the doctrine or by religious faith, a situation which sometimes occurs, in both varieties, in the context of Hindu systems of doctrine."
Sources:http://www.accesstoinsight.org/tipitaka ... .than.htmlhttp://www.accesstoinsight.org/lib/auth ... ay_27.htmlhttp://www.accesstoinsight.org/lib/auth ... iness.htmlhttp://www.accesstoinsight.org/lib/auth ... iness.html