This is a good issue to discuss since it can give some insights. Thanks for bringing it up.
– I am going to put it in the point form. If anyone has questions, please refer to specific bullet numbers.
1. Abhidhamma starts at a basic fundamental level. Rupā are categorized into 28 types, cittā into 81 (121) types, etc. Such a detailed analysis provides a solid foundation for Buddha Dhamma.
– However, Abhidhamma cannot “break down” subtle concepts like anicca or the Noble Truths to that level directly; see #4 below.
2. An analogy is as follows. Physics (in particular elementary particle physics) provides the backbone for science in general.
– However, physics CAN NOT explain how living cells arise. Biology starts not with physics, but with the ASSUMPTION that living cells exist. They don’t know how living cells came into existence. Even though living cells are made of atoms and physics understands atoms, there is a gap from there to a living cell that has not been explained.
– I discussed that in the “Origin of Life” section.
3. However, Buddha Dhamma can explain how living cells arise. They come into existence via the laws of kamma, dictated by Paticca Samuppada (as I explained in that section on “Origin of Life.”)
4. In the same way, Tilakkhana and Four Noble Truths cannot simply be analyzed in terms of 81 (121) citta, 52 cetasika, and 28 types of rupa.
– However, it is again Paticca Samuppada that is the bridge between those fundamental entities and deep concepts of Tilakkhana and Four Noble Truths.
5. Paticca Samuppada is explained in the Sutta Pitaka: SN 12.1 through to the end.
– Paticca Samuppada is explained in DETAIL in the “Vibhaṅgapakarana” (of the Abhidhamma Pitaka) in the “Paṭiccasamuppāda vibhaṅga” section.