Imagination....
Something passes by the human flesh...
Eyes - The rods and cones senses the wavelength of the image causing the lens in the eye to focus and the cornea to direct the correct amount of light to the fovea centralis where the image is sensed. The optical nerve then directs the many patterns and wavelengths of light to the brain for processing. The cornea is lubricated with tears and the eyeball must remain clear for the image to be sensed.
Ears - The noise passed by bones in the ear, which amplify the sound, and the cochlea changes the sound to neurological signals, which tells the brain the frequency of the sound.
Nose - Humans can distinguish more than 10,000 different smells (odorants), which are detected by specialized olfactory receptor neurons lining the nose.... It is thought that there are hundreds of different olfactory receptors, each encoded by a different gene and each recognizing different odorants.
Touch - Your skin contains tiny nerve endings that create your sense of touch. When you experience sensations such as pain or heat or cold, or feel things that are soft or sticky or sharp, the bottom layer of your skin, called the dermis, sends messages to your brain about the sensation.
The brain senses the object passing his way and then the motor neurons then search the memory neurons for references as to what this object is. If it is something that the dream deems pleasant the spiritual recptors inside the heart then triggers the spiritual senses and the body then senses spiritual E/c2... E (Energy, motivation, warmth, love, delight) c2 (faith, hope, charity, joy, goodness, etc.).
There is also an unconsciousness mental processor that takes what has been stored in the brain and builds things like imagination and dreams. These imagings either produce E (Energy, motivation, warmth, love, delight) c2 (light, faith, hope, charity, joy, goodness, etc.) or the opposite of E/c2 ... Z/d (absoute zero, cold, repulsion, hate, disappointment) d(darkness, fear, despair, greed, sorrow, corruption, etc.).
All done by a brain with only 100 billion brain cells. You must think that processing involved for the brain to sense an object before it in multimedia must take in itself 10 billion brain cells as the brain builds an imaginary scenario of what just happened.
It is the atheist who has the very good imagination to believe that all of this came into reality by itself.