Is there awareness of impermanence during the formless meditations?
If you choose to see things as they are or investigate the Dhamma. Since in the 8th Jhana there is a residue of Perception and Feeling hence you should direct your observation to understand the impermanence of feeling or impermanence of what is felt if you what to develop insight into the 3 marks of existance.
A person taking the Arupa Jhana route attains the final goal by going though Nirodha Samapathi (
cessation of perception and feeling)
See: Raho,gata Sutta for further details.
In summary, to perceive the following:
- Taste: Tongue
- Sound: Ears
- Sight: Eyes
- Object: Touch (cant remember the 5th sense.. need some sleep.. will add later )
That which is formless & beyond all attributes cannot be 'sensed' or perceive using a Sense of the Body (or even an Xray or Infra red vision).
That which has no form, is infinite & all pervasive cannot be measured like an physical object with 'defined' dimensions.
It 'comes' as an experience. :) It's not something you can switch on, on demand; Unless you are enlightened - Then you already know that everything is infinite. At that point your senses & your body and everything else is just a virtual construct.
I thought this might be relevant:
The formless meditations are part of the imageless realm arupa-bhava. According to Stefan Anacker in his book on Vasubandhu
formless meditation is still one pointedness of citta toward an examined range of events... the imageless realm comprises any state where all senses except the mental consciousness are suspended... the first five consciousnesses no longer perceive their object
Emphasis mine. I find the idea of citta without any sense consciousness at all completely baffling! I think that unless your canon explicitly says, probably best to make up your own mind.