In this extract, Frankl talks about how in one of the most deplorable conditions that human beings could imagine, some were able to coax their minds to create the state of existence that they desired. Pages 54 to 59.

A key part is a fact that when the soul or human consciousness is empty, a small amount of negativity can fill it evenly and completely.  

Man's Search For Meaning, By Viktore E. Frankl