Yes. It is good to understand how unimaginably small a suddhāṭṭhaka is. I have not seen a direct reference to the “size” of a suddhāṭṭhaka in the Tipiṭaka. But we can get a good idea the following way.
1. Any “rupa” (experienced with the five physical senses) is above the suddhāṭṭhaka stage. A suddhāṭṭhaka is the smallest “rupa.”
- Thus, a “rupa” can be light, sound, food particles, particles that carry odors (scents), or physical touch experienced by the body.
2. The easiest way is to look at particles of light or photons.
- A photon in the visible range is about 2 eV in energy units.
- In comparison, the “mass” of a proton (roughly the mass of the smallest atom) is about 938 MeV or roughly a billion eV.
- Thus, a photon in the visible range is about a billion times smaller than an atom.
- My quoted number of ” a billion times smaller” is an understatement because there are even smaller rupa!
3. Such unimaginably small energies can be created by javana citta in our minds, especially when “energized” by lobha, dosa, or moha.
- As we have discussed, a hadaya vatthu (seat of the mind) or a pasada rupa (like cakkhu, sota,..kaya responsible for the detection of the five types of external rupa) is a single suddhāṭṭhaka each.
- For example, a cakkhu pasada rupa that detects light is a single suddhāṭṭhaka. A hadaya vatthu (seat of the mind) is a single suddhāṭṭhaka.
4. Our physical bodies (that are hugely bigger) are just inert shells “powered by” such an unimaginably tiny set of hadaya vatthu and pasada rupa.
- One analogy is to consider a huge oak tree and a seed that gives rise to it. That tiny seed gets all the “material” from the earth and grows into a huge tree.
- In the same way, a tiny gandhabba (with a set of hadaya vatthu and pasada rupa) grows into a physical body by taking in food, first from the mother and then by eating.
P.S. Of course, the Buddha could not give such an analogy those days since people knew nothing about atoms and photons. We are fortunate to be able to make such comparisons these days.