Depends upon what is meant by paramatha. I am not sure the Theravada tradition speak uniformally on that matter, even as late as Buddhaghosa. Nanamoli in a footnote in his PATH OF PURIFICATION, pages 317-8, states: "In the Pitakas the word sabhaava seems to appear only once...," it appears several times in Milindapanha, and it is used quite a bit in the PoP and it commentaries. He states it often roughly corresponds to dhaatu, element and to lakkhana, characteristic. An interesting passage from the PoP reads:if his main contender was Pudgalavavada and the Theravadins asserting that the Five Aggregates were paramatha,
"On the contrary, before their rise [the bases, aayatana] they had no individual essence [sabhaava], and after their fall their individual essence are completely dissolved. And they occur without mastery [being exercisable over them] since they exist in dependence on conditions and in between the past and the future." Page 551 XV 15.
And another, XV 21:
"These are elements (dhaatu) since they cause [a state's] own individual essence [sabhaava] to be borne (dhaarenti)."
It is a problem with language, it seems, and no matter how hard we try not to, we tend to end up making whatever it is we are talking about solid. I think the Pali Abhidhamma seems have tried to resist this, even into the later commentaries, and it probably did better than some other systems, but there is an obvious reification going on some of the more modern abhidhamma discussions that really does not seems warranted from the earlier Abhidhamma, particularly the Abhidhamma Pitaka, nor from the suttas.
What kind of "ultimate things" are dhammas? Piatigorsky, in his studies of the Theravadin Abhidhamma Pitaka texts (THE BUDDHIST PHILOSOPHY OF THOUGHT 1984, 181) points out dharmas are not substances; they are not 'things' in and of themselves:
We simpy cannot say that 'a dharma is... (a predicate follows)', because a dharma, in fact, 'is' no thing, yet [it is] a term denoting (not being) a certain relation or type of relation to thought, consciousness or mind. That is, dharma is not a concept in the accepted terminological sense of the latter, but a purely relational notion.
Nyanaponika ABHIDHAMMA STUDIES, page 41 BPS; page 42 Wisdom. wrote:By arranging the mental factors in relational groups a subordinate synthetical element has been introduced into the mainly analytical Dhammasangani. By so doing, the danger inherent in purely analytical methods is avoided. This danger consists in erroneously taking for genuine separate entities the “parts” resulting from analysis, instead of restricting their use to sound practical method with the purpose of classifying and dissolving composite events wrongly conceived as unities. Up to the present time it has been a regular occurrence in the history of physics, metaphysics, and psychology that when the “whole” has been successfully dissolved by analysis, the resultant “parts” themselves come in turn to be regarded as little “wholes.”
http://www.zeh-verlag.de/download/dhammatheory.pdf wrote:In the Pali tradition it is only for the sake of definition and description that each dhamma is postulated as if it were a separate entity; but in reality it is by no means a solitary phenomenon having an existence of its own. . . . If this Abhidhammic view of existence, as seen from its doctrine of dhammas, cannot be interpreted as a radical pluralism, neither can it be interpreted as an out-and-out monism. For what are called dhammas -- the component factors of the universe, both within us and outside us -- are not fractions of an absolute unity but a multiplicity of co-ordinate factors. They are not reducible to, nor do they emerge from, a single reality, the fundamental postulate of monistic metaphysics. If they are to be interpreted as phenomena, this should be done with the proviso that they are phenomena with no corresponding noumena, no hidden underlying ground. For they are not manifestations of some mysterious metaphysical substratum, but processes taking place due to the interplay of a multitude of conditions. Prof. Dr. Y. Karunadasa, THE DHAMMA THEORY, page 9.
Harvey, in his excellent INTRODUCTION TO BUDDHISM, characterizes the Theravadin position, page 87: wrote: "'They are dhammas because they uphold their own nature [sabhaava]. They are dhammas because they are upheld by conditions or they are upheld according to their own nature' (Asl.39). Here 'own-nature' would mean characteristic nature, which is not something inherent in a dhamma as a separate ultimate reality, but arise due to the supporting conditions both of other dhammas and previous occurrences of that dhamma."
Dhammas are "ultimate things" only as a way of talking aspects of the relational flow of experience, not in terms of describing static realities. In other words, dhammas are empty of self.A.K. Warder, in INDIAN BUDDHISM, page 323, discussing the Pali Abhidhamma commentarial literature, states: wrote: "The most significant new idea in the commentaries is the definition of a 'principle' or element (dharma): dharmas are what have (or 'hold', 'maintain', dhr. is the nearest equivalent in the language to the English 'have') their own own-nature (svabhaava). It is added that they naturally have this through conditions."
Now, I am sure there will be those who will disagree, which is fine. This is about as much as I am going to defend the Abhdhamma.