A dichotomy /daɪˈkɒtəmi/ is a partition of a whole (or a set) into two parts (subsets). In other words, this couple of parts must be
Such a partition is also frequently called a bipartition.
- 1. jointly exhaustive: everything must belong to one part or the other, and
- 2. mutually exclusive: nothing can belong simultaneously to both parts.
The two parts thus formed are complements. In logic, the partitions are opposites if there exists a proposition such that it holds over one and not the other.
Treating continuous variables or multicategorical variables as binary variables is called dichotomization.
One of the problems inherent in Twitter, and social media in general, is that it gives a virtual soapbox to people who react and respond to information without really thinking about the context or implications of that information. Tweeters assume that anyone who opposes A must therefore support B, because there can be no other alternatives to the A-B dichotomy.
One of the problems inherent in today's mainstream Media Industrial Complex is that our trusted information sources do the exact same shit and get rewarded handsomely for it. Think-tanks and political consultants leverage people's instinct to dichotomize: They propagate the message that, if you support A, then B is the opposite of everything you hold dear and thus your enemy. They traffic in fear, because fearful people buy stuff to make them feel better.
B is not your enemy. A is not your enemy. Dichotomistic thinking is your enemy.