Yesterday Ajahn explained inner and outer dhammas in depth:
2020-08-20 Thur. CN Zoom discussion:
Q: Why citta is innermost?
A. Sujin: Because citta arises all the time and there are cetasikas arising with one moment of citta, so when one citta arises there must be many cetasikas arising with it in one moment, so what is the inner, innermost, citta or cetasikas? Because sometimes some cetasikas do not arise at all, but citta is always there, the chief of experiencing an object, only one object at a time.
And citta itself, without the akusala cetasikas or kusala cetasika would be pure, but it isn't pure, it's tainted by the akusala cetasikas, so what is outside to paint the citta?
Even a moment of akusala citta, citta itself not including cetasikas is pure, but akusala cetasikas are that which make it tainted, impure. So what is the innermost?
No matter how many cetasikas arise with it, citta cannot be cetasikas and cetasikas cannot be citta, so citta is the chief of experiencing, no matter whatever level of kusala or akusala, citta itself will never be akusala or kusala, because is pure and when akusala cetasikas arises with it is not pure, not kusala, and when kusala cetasikas arise with it, it is kusala, but citta itself is pure, so it is the innermost, not akusala yet until akusala cetasikas arise with it.
At a moment when there is attachment, we can understand that moment by thinking about that which is clinging to something, but not knowing or understanding citta which is the innermost.
So a cetasika can be known as it is when there are the conditions for its arising and appearing, but for citta, it arises all day along but no one can understand the innermost, because one just known the moment of akusala or the kusala moment. Is it a bit clearer, just a little bit?