"Meditations"

"How often, asleep at night, am I convinced of just such familiar events - that I am here in my dressing gown, sitting by the fire - when in fact I am lying undressed in bed! Yet at the moment my eyes are certainly wide awake when I look at this piece of paper; I shake my head and it is not asleep; as I stretch out and feel my hand I do so deliberately, and I know what I am doing.

All this would not happen with such distinctness to someone asleep. Indeed! As if I did not remember other occasions when I have been tricked by exactly similar thoughts while asleep! As I think about this more carefully, I see plainly that there are never any sure signs by means of which being awake can be distinguished from being asleep.

The result is that I begin to feel dazed, and this very feeling only reinforces the notion that I may be asleep." (Meditations, 13)

how very the true.