j: did you understand the sense of the problem in theoretical [quantum mechanics] which we solved in our course today? p: it was just some brain-wanking
act of spending one's time with very complicated theoretical problems which, when solved, do not serve for anything useful or practical
"j: did you understand the sense of the problem in theoretical [quantum mechanics] which we solved in our course today? p: it was just some brain-wanking" What is the definition of "brain-wanking"?