  There are inherent limits in classical computation for it to serve as an
adequate model of human cognition. In particular, non-commutativity, while
ubiquitous in physics and psychology, cannot be sufficiently handled. We
propose that we need a new mathematics that is capable of expressing more
complex mathematical structures to tackle those hard X-problems in cognitive
science. A quantum mind approach is advocated and we hypothesize a way in which
quantum computation might be realized in the brain.
