>>17846622In my opinion, the most likely physical cause is quantum fluctuations inside the brain cells.
There is a body of theories, the "quantum mind", which attempt to describe this phenomenon.
Funny enough, it is explained quite eloquently in Sword Art Online: Alicization.
Also, you must understand that the fundamental aspect of what we may call "consciousness", i.e. the ability to "make choices" (either randomly or depending on some environmental factor) about which action to take, is also visible in the behavior of elementary particles, such as photons.
