Yes. My statement there could have been worded with more explanation.
– By the way, firewns is referring to #4 of my previous reply.
So, let me state the steps in the correct order in what happens when a baby is conceived in a womb.
1. First, a gandhabba (mental boy) arises when a new bhava is grasped. For example, if a Deva dies and becomes a human, a human gandhabba arises at that moment.
2. Then that gandhabba waits for a suitable womb. When one becomes available, the gandhabba is pulled into that womb by kammic energy.
3. That gandhabba has the blueprint for the vital parts of a new human body (for example, if one is to be born blind, then it would not have the cakkhu pasada rupa). However, other physical characteristics (body color and even body shapes) come from the zygote produced by the two parents.
“Buddhist Explanations of Conception, Abortion, and Contraception”
– That is what I referred to there. The “nama” part comes from the gandhabba and some parts of the “rupa” comes from the zygote.
– In that process, “vinnana paccaya namarupa” step involves “patisandhi vinnana” which is essentially gandhabba. It gives rise to the seed of the physical body of a new human (namarupa” there).
– This is why some terms may have different meanings in different contexts.
4. In Idapaccaya PS, “namarupa” refers to “mental images” that arise while thinking about a kammic action: “avijja paccaya sankhara”,.. to “vinnana paccaya namarupa”.
So, one needs to spend some time and figure out what happens. It is not possible to mechanically put in definitions.
You wrote: “However, hadaya vatthu would have to be formed when the gandhabba is formed, as it is part of the mental body.”
– Yes. That is correct.
– But the baby’s physical body needs to build the physical eyes, ears, etc to be able to “sense the external world” as we are discussing in the new series:
“Buddha Dhamma – A Scientific Approach”
So, I hope the answers to the other questions are clear now.
– If not, please feel free to ask.
To emphasize, terms of the PS processes (Uppatti and Idapaccaya) can have very different meanings. The twp processes are discussed separately, for example, in:
“Viññāna Paccayā Nāmarūpa”
“Nāmarūpa Paccayā Salāyatana”