Cave explorers know all too well what impact absolute darkness and silence have on mood and mind. If it was not for the senses, one might just as well live in a vacuum, where neither space nor time have any meaning and life itself takes on another form. It is only due to the senses that the mind does not lose its grounding, for the border-lines between what is and what not, are uncertain and blurred. Dream and reality, generally two different states, mingle with and melt into each other, like watercolours, or the sounds of a wind organ. Of course, the mind always relies on the senses to deal with the reality it lives in, has to adjust to and, finally gets accustomed to, so routines can develop for everyday duties, which in turn,...