Duden 49: "When students tell me, 'I must take care of my system,' or, 'My system cannot take this stress,' or 'I cannot survive in this system,' they believe what they say. [...] They perceive themselves in terms of feedback within a psychophysiological system. Not only in biology and sociology, but also, increasingly, in areas such as literary studies and art history, students are taught to look for complex feedback and communication within a system."