For me, the question arose spontaneously:
“What if everyone else feels exactly the same as you?”
Followed by:
“What if you’ve been assuming that your awareness is somehow uniquely you, but actually experience feels exactly the same for everyone?”
It was a light-bulb moment, the answers immediately apparent. My understanding of the world shifted profoundly. My meditations up till then had been forward-looking, and suddenly it was like a mirror appeared before me - with an almost deja vu sense of “my” awareness recognising itself for this first time in this body.
The days that followed were blissful. A deep, slow resonant sensation when I tuned into the realisation, adopted the new perspective. A mind constructs a model of the world. New information and experience is mapped onto it. If the mapping if poor, an unpleasant tension arises. If the mapping is good, then it feels good. A multitude of ideas, memories, concepts - past and present - suddenly mapped perfectly. A deep sense of peace persisted for a few days, before a fairly grim crash and eventual return to a new normality.
It found this particular realisation somehow impossible to communicate. Once it clicked, it felt almost obvious. I attempted to explain it to someone else, but one can’t force the moment of understanding. There’s the sense of this particular realisation being somehow like a personal riddle.