Argumentation (or Reasoning) Schemes: Patterns of reasoning or argument — both very general ones, and also more detailed instances of those general ones.These schemes thus represent types of argument or reasoning. Accordingly, there are schemes in general, for example, for argument from analogy or argument from authority. (General analogy: “X is like Y, and Y has property P, so probably/presumably X has property P also.” General Authority: “A says S; A is an authority about things like S; so probably/presumably S .”) And there are also more specific schemes representing sub-types of these general patterns. (e.g., Enumerative analogy: “Instances of Aa-1,a-2, a-3 ,etc. have property X , so instance of Aa –n will have property X “; a priori analogy: “Act A deserved treatment T ; act B is relevantly similar to A; so act B deserves treatment T.”) Associated with each scheme is a set of critical questions that have to be answered appropriately for any argument that is an instance of that scheme if it is to be a cogent argument. In addition, according to one current conception of fallacy, a fallacy is an inappropriate use of an argumentation scheme (for an example is an inappropriate appeal to authority, such as appealing to a physician — a medical authority — in support of a pro- or con- point of view about abortion, which is a moral, not a medical, issue).
Source: ‘What is Good? What is Bad? The Value of All Values across Time, Place and Theories’ by John McMurtry, Philosophy and World Problems, Volume I-III, UNESCO in partnership with Encyclopedia of Life Support Systems: Oxford, 2004-11.