A Google search of this word shows no documents, so I may be able to claim credit for coining it. This is really the concept I am trying to promote. A yardstick, a way to classify arguments and trains of though. On one extreme (high dichotomaticity) would be classical DT: I am right you are wrong, we are great they suck. On the other extreme  (low dichotomaticity) would be clearly goal-oriented thinking “What is the nature of the problem and how do we solve it?” My suggestion is, when thinking about any argument or train of thought, first ask “Is the degree of dichotomaticity appropriate for the situation? Is it too dichotomous?“