Waking up in a human body for the first time is no different than waking up from sleep. W, finding himself lying on a blue mat in a big hall notes his surroundings, reaches for memories, and the memories show up. W knows he is a young man, lives in the mountains, has studied religion for ten years since leaving his parents home, loves his best friend, hates the persistent cold, is about to lead chanting, needs some tea, and wonders why he feels so strange this morning as if an unfamiliar presence has arrived. During morning meditation, calmed by ceremony and food, W takes a few moments to shift his attention from his breath, open up to the new sensation, and explore. If something is new it feels exactly like himself - perhaps he is entering the next jhana? Describing this experience to his teacher, W notices eyebrows darting briefly up and down in a very uncharacteristic display of emotion.
A similar setup, a memory hack, is used to trick the androids in Blade Runner who think they are human because they can talk about their families, childhood, and personal thoughts but find out later that their past memories are artificial and loaded into their data storage at the factory. How would they know that they didn't live those memories? Why would they question what they recall is true?
How do we know every morning when we wake up if we have lived our lives up to that point or if we are waking up in a new body already filled with memories? How do we know every morning that we are the same person that we were when we went to sleep?