A recent neuroscience study hints at how our brains distinguish between what we imagine and what we observe.
https://www.quantamagazine.org/is-it-real-or-imagined-how-your-brain-tells-the-difference-20230524/
Is It Real or Imagined? How Your Brain Tells the Difference. | Quanta Magazine
New experiments show that the brain distinguishes between perceived and imagined mental images by checking whether they cross a “reality threshold.”
Quanta Magazine