" Human consciousness cannot be a passive observer of the outer world, just interpreting the input signals that are being received by the brain from the external world. Rather, it compares the fitness of a person's inner world -- feelings, perception, imagination, dreams, desires, etc. -- with the external world, allegedly accepted as 'objective reality' outside individual consciousness. However, such an objective reality cannot be so objective as it is believed to be. Due to various internal processes to achieve a balance between the inner and outer worlds, consciousness insensibly changes the physical characteristics of reality, making it a subjective phenomenon, at least to a large extent. For this reason, in order to determine what is real (outside of human consciousness) and what is just a subjective experience, it is actually a difficult job. "

― Elmar Hussein