eight aspects of the main stage of the dhyanas
These are the eight aspects from the state with both concept and discernment, to the state with neither absence nor presence of conception. These are four dhyanas and four formless spheres (or states):
1) the first dhyana is a state with both concept and discernment.
2) the second dhyana is a state without concept but with just discernment.
3) the third dhyana is a state without delight but with bliss.
The four formless spheres are:
1) the sphere of infinite space.
2) the sphere of infinite consciousness.
3) the sphere of nothing whatsoever.
4) the sphere of neither presence nor absence, also called the sphere of neither absence of conception nor presence of conception. (RY)