Answer

I don’t know exactly what you mean, but dilemma arguments usually assume a dichotomy. For example: there is no point in giving exams, because the diligent students will study even without them, and the lazy ones won’t study even with them. The mistake here is the dichotomous assumption that the world is divided into pathologically lazy people and pathologically diligent people. But there is a continuum of levels of diligence, and for some of the intermediate shades, exams can be useful by getting them to study. More generally, search here on the site for what I wrote about the sorites paradox. That is another angle on the problem with dichotomous thinking.