Informal Fallacies: Presumption
Fallacies of presumption — false dilemma, begging the question, loaded question, and circular reasoning — where the argument assumes what it needs to prove.
Arguments That Assume Too Much
Fallacies of presumption build their conclusions into their premises, often so subtly that the listener does not notice. They feel logical because the conclusion seems to follow, but the argument has smuggled in an assumption that has not been established.
False dilemma (false dichotomy) presents only two options when more exist. 'You are either with us or against us.' 'We can either fund the military or fund schools, not both.' In most policy debates, there are dozens of possible positions between the two extremes. False dilemmas are the favorite tool of political rhetoric because they force people into camps and make nuance seem like weakness.
Begging the question (circular reasoning) assumes the conclusion in the premises. 'Free speech is important because people should be able to say what they want.' The premise and conclusion say the same thing in different words. Nothing has been demonstrated. Watch for this when an argument feels self-evident but offers no actual evidence.