text: physical constituents. For example, water is nothing 
  more than H2O molecules, and understanding everything 
  about H2O molecules is to understand everything there is 
  to know about water. But consciousness is not like this. 
  Knowing everything there is to know about the brain, or 
  any physical system, is not to know everything there is to 
  know about consciousness. Consciousness, then, must 
  not be purely physical.[27] 