Argumentation schemes represent, at an abstract level, forms of reasoning used in everyday conversational argumentation, and in other contexts, such as legal and scientific argumentation (Bench-Capon and Prakken, 2010). Many of the most common schemes, still recognized as centrally important in the literature, were identified in (Hastings, 1963), (Perelman and Olbrechts-Tyteca, 1969), and (Kienpointner, 1992). The schemes described and explained in chapter 9 of (Walton, Reed and Macagno, 2008) include the ones for argument from expert opinion, argument from sign, argument from commitment, argument from lack of knowledge, practical reasoning (argument from goal to action), argument from cause to effect, the sunk costs argument, argument from analogy, three kinds of ad hominem argument, and four kinds of slippery slope argument. Historically, schemes are the historical descendants of the topics, representing common types of arguments, originally catalogued by Aristotle. Two schemes that we will have to use in this paper are the one for argument from expert opinion and the one for argument from lack of knowledge, widely known in the literature on fallacies as the argument from ignorance. To explain how schemes work, it is best to begin with a description of these two. The simplest, and in many ways the most intuitive scheme for argument from expert opinion, can nicely be expressed in the form below. Major Premise: E is an expert. Minor Premise: E asserts that A is true (false). Conclusion: A is true (false). The reader might be interested comparing this form with a slightly more complex version of it given in (Walton, Reed and Macagno, 2008, 310). This form of argument is defeasible, meaning that it only holds tentatively in a given case, subject to the possibility of new evidence might come in that can defeat it. It is important to recognize that argument from expert opinion is subject to critical questioning, and that therefore it needs to be treated as an open-ended type of argument rather than as a conclusive one of the kind that might be represented by deductive logic or any other monotonic system where the addition of new premises will not make the argument default. This set of critical questions matches this scheme for argument from expert opinion (Walton, Reed and Macagno, 2008, 310). CQ 1 : Expertise Question. How credible is E as an expert source? CQ 2 : Field Question. Is E an expert in the field that A is in? CQ 3 : Opinion Question. What did E assert that implies A? CQ 4 : Trustworthiness Question. Is E personally reliable as a source? CQ 5 : Consistency Question. Is A consistent with what other experts assert? CQ 6 : Backup Evidence Question. Is E's assertion based on evidence? CQ 1 questions the expert's level of mastery of the field F. CQ 4 questions the expert's trustworthiness. For example, if the expert has something to lose or gain by saying A is true or false, this evidence would suggest that the expert may not be personally reliable. The asking of the critical question defeats the argument temp...