The phenomenon of consciousness has caught the attention of many Philosophers and Scientists throughout history and innumerable papers and books have been published devoted to the subject. However, no other biological singularity has remained so resistant to scientific evidence and “persistently ensnarled in fundamental philosophical and semantic tangles.” Under ordinary circumstances, we have little difficulty in determining when other people lose or regain consciousness and as long as we avoid describing it, the phenomenon remains intuitively clear. Most Computer Scientists believe that the consciousness was an evolutionary “add-on” and can therefore be algorithmically modelled. Yet many recent claims oppose this theory. Sir Roger Penrose, an English mathematical physicist, argues that the rational processes of the human mind are not completely algorithmic and thus transcends computation and Professor Stuart Hameroff's proposal that consciousness emerges as a macroscopic quantum state from a critical level of coherence of quantum level events in and around cytoskeletal microtubules within neurons. Although these are all theories with not much or no empirical evidence, it is still important to consider each of them because it is vital that we understand the human mind before we can duplicate it.

Another key problem with duplicating the human mind is how to incorporate the various transitional states of consciousness such as REM sleep, hypnosis, drug influence and some psychopathological states within a new paradigm. If these states are removed from the design due to their complexity or irrelevancy in a computer then it should be pointed out that perhaps consciousness cannot be artificially imitated because these altered states have a biophysical significance for the functionality of the mind.