  Let us say that a scenario is a (more-or-less detailed) story, which may be possible or impossible. (So, for example, there is a scenario in which someone squares the circle.) Corresponding to a scenario is what we can call a hypothesis: that the scenario is possible. So, for example, the hypothesis corresponding to a circle-squaring scenario is false. There are a variety of “inverted qualia” scenarios in the literature—almost  always involving color perception—whose corresponding hypotheses differ in plausibility. These hypotheses are used as premises in a number of philosophical arguments, discussed in section 3 below.