Arguments from Popular Opinion Scheme (Ad Populum)

aka, the Ad Populum Argument Scheme

* If a large majority in a particular reference group G accepts A as true (false), then there exists a defeasible presumption in favor of (against) A * A large majority accepts A as true (false). * Therefore, there exists a presumption in favor of (against) A This form of the argument might use polls or statistics meant to measure public opinion. This argument may or may not accurately reflect a real world state, but the fact that so many people commit to it, gives it a presumption that it does accurately reflect a real world state. (Walton, Reed, Macagno. 125) Critical Questions regarding the argument scheme. 1. Is it really the case that a large majority of the particular reference group accepts A as true? 2. Is there any other available evidence that would support the assumption that A is false? 3. What reason is there for thinking that the view of this large majority is likely to be right?

In order to determine if it does accurately reflect a real world state, whatever claim is being made must be verified.  Data gathering must be done with an emphasis on data about what its causes are, where it came from, what it interacts with, what it depends on and what it causes. 

Variant of the Basic Form of Ad Populum Argument Scheme
1. Position to Know
2. Expert Opinion
3. Deliberation
4. Moral Justification (Excuse subtype)
5. Moral Justification
6. Common Folks
7. Rhetoric of Belonging
8. Snob Appeal
9. Appeal to Vanity

Walton, Reed, Macagno. Argumentation Schemes. New York: Cambridge University Press, 2008, pgs 122-131

Position to Know Ad Populum Argument Scheme

Depending on preferred classification style, it can be a subcategory of Ad Populum or a subcategory of Source-based Arguments. Ad Populum arguments are inherently weak and prone to exploit prejudice. They are typically categorized as fallacies but in many instances they can be reasonable arguments and the best kind of evidence available to make a rational decision (Walton, Reed, Macagno. 121).

The degree of commitment to the truth of the argument varies from person to person, however, if artifacts are available for review in support of the Ad Populum argument, they strengthen the persuasiveness of the argument, and the Ad Populum argument takes on the characteristics of another more persuasive reasoning scheme.

The type of reasoning scheme that it transitions to must be assessed with regard to all that is known about it in order to determine which scheme it has transitioned to.

Major Premise: a person a is in a position to know about things in the domain of a subject which contains proposition P. Minor Premise: a asserts that P is true (or false). Conclusion: P is true (or false). Critical Questions about the argument 1. Is a in a position to know whether P is true (or false)? 2. Is a an honest (trustworthy, reliable) source? 3. Did a assert that P is true (or false)? Reference for this example in the book Argumentation Schemes Douglas Walton, Legal Argumentation and Evidence. University Park: Pennsylvania State University Press, 2002, p. 46. Reference for this page in Argumentation Schemes Walton, Reed, Macagno. Argumentation Schemes. New York: Cambridge University Press, 2008, p. 309