I recently found a forum post where one venerable teaching Objective Reality using the evidences in EBTs. What do you think about his explanation?
1.18. The idea of considering paramatthadhammas as existents can be verified with evidence from the canon itself. In number of suttas the Buddha mentions rūpa, vedanā, saññā, saṅkhāra and viññāṇa to be dukkha (natures that bring suffering). When it is mentioned in suttas as “Rupaṃ dukkhaṃ” and “Vedanā dukkhā” usage of similar nominal case endings in rūpa and dukkha and vedanā and dukkha suggests that the terms are in apposition. It means what is referred by the term rūpa is the same that is referred by the word dukkha. The same should be understood with regard to the other two terms, vedanā and dukkha.
Then in the Acelakassapa Sutta, when being questioned by Acelakassapa whether there is no dukkha “Kiṃ nu kho, bho Gotama, natthi dukkhaṃ (Venerable Gotama, isn’t there dukkha)?”, the Buddha gave the direct answer, “Na kho, Kassapa, natthi dukkhaṃ. Atthi kho, Kassapa, dukkhaṃ (Kassapa, it is not that there is no dukkha. There is, indeed, dukkha)”.
Therefore, as for the teachings of the Buddha, if dukkha exists, rūpa and vedanā (and the remaining aggregates of clinging - upādānakkhandha) also should exist, because dukkha is the five aggregates (rūpa, vedanā, saññā, saṅkhāra and viññāṇa).
It is very evident that the Buddha advocated the existence of dukkha and, also, propounded that what he considered as dukkha is the five aggregates, which in turn leads to the inference that five aggregates do exist according to him. Five aggregates are the citta, cetasika and rūpa which were explained above.
In the Puppha Sutta of Saṃyutta Nikāya, the Buddha clearly advocates that he accepts the idea that five aggregates i.e., rūpa, vedanā, saññā, saṅkhāra and viññāṇa, that are impermanent, subject to change and which bring forth suffering do exist.
Moreover, in number of suttas the Buddha has clearly advocated the existence of spiritual qualities such as eight-fold noble path (ariyo aṭṭhaṅgiko maggo), seven factors of enlightenment (satta bojjhaṅgā), four-fold-mindfulness (cattāro satipaṭṭhānā), three types of feeling (tividhā vedanā) and so forth. These are also concrete evidences to prove that according to the Theravāda canon the Buddha himself has propounded the existence of paramatthadhammas.
Venerable Maggavihari at IIT