Alex123 wrote:
2) Does rūpa translates as "matter" in the modern materialistic sense or is it only perceived matter?
The provenance of the "modern" perspective can actually be traced to the Abhidhammic methodology of classifying
rūpa as whatsoever is contactable by the 5 "material" sense bases, versus
nāma which is contrasted as
arūpa. At least from the Pali suttas, as observed by Sue Hamilton, this limitation to the 5 senses is nowhere to be found. My suspicion for why the Pali Abhidhamma opted for this classification is that it is a borrowing from the Sarva Abhidharma, or at least a proto-Abhi text that predates both schools. I've seen at least one (Mula)-Sarva Agama sutra, where
nāma is defined as feeling, perception, volition
and consciousness, instead of the more standard definition found elsewhere in the Pali and Chinese. This sutra may be the source for the Sarva Abhidharmic analysis of
rūpa versus
arūpa, which was eventually adopted in the Pali Abhidhamma.
If one looks to the Upanisadic literature that can be attested confidently as being pre-Buddhist, we get the sense that
rūpa means "appearance". I think the Buddha adopted and preserved this usage, the most notable example being DN 15's descent of consciousness into the womb being the condition for
nāmarūpa forming in the womb.
But, the Buddha went further than the Upanisadic antecedents and expanded the role of
nāmarūpa beyond the instance of rebirth consciousness. Every instance of contact, according to the Buddha, would be governed by the same principle, ie the 5 Aggregates. That's all there is to Suffering. According to MN 28, contact arisen from the mind, dhammas and mind-consciousness can give rise to
rūpa as
rūpūpādānakkhandha (the clinging aggregate of rūpa). This does not quite tally with the Abhidhammic method which focusses on the
prequel to contact. MN 28 and the general 5 Aggregate analysis, IMHO, deals with the
sequel to contact.
What
rūpa seems to mean in the context of contact happening is that experience can have a
rūpiya (
rūpa functioning adjectivally) dimension to it. DN 15 is probably the best explanation of what types of contact occur, and how these types of contact operate in the context of bare sensory impression and its sequel "delineation". That sutta explicitly discusses the
ākāra liṅga nimitta uddesa (quality, attribute, sign, mark) of each of
nāma and
rūpa that would be necessary for the 2 types of contact to operate in relation to
nāma and
rūpa.
Rūpa operates in
paṭighasamphassa (bare sensory impression), but surprisingly, there can be
paṭighasamphassa of
nāmakāya. This agrees with the possibility in MN 28, ie that the contact at the mind-base can also give rise to
rūpa.
By and large, if one were looking at
rūpa in the context of the quality of sense objects, it probably suffices to just talk about "material" qualities. However, given that
rūpa is also discussed as an Aggregate, it is important to keep in mind that
rūpa can also arise in the relation to immaterial qualities. I think rather than using the terms "material" and "immaterial", it would probably be far better to use the
ākāra liṅga nimitta uddesa terminology to describe
rūpa. These synonyms point back to "appearance", in the sense of how does a contact appear in the broadest sense of solidity, liquidity, movement, energy, and spatiality.